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1
Viaud, Marc. "Role of the corticostriatal projection in learning and memory functions." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63887.
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Bruce, Kenneth R. "Effects of alcohol on emotionally salient memory." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34509.
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Social drinkers (healthy males aged 18--34) participated in three experiments that examined some of the mechanisms that may be responsible for the effects of alcohol on emotionally charged memory. In a study on incidental learning, alcohol enhanced neutral, positive and negative memory, possibly by a nonselective consolidation mechanism. Alcohol's enhancement of memory was found to not be associated (contingently related) with its incentive reward and relief effects. In another study on intentional learning, alcohol enhanced positive memory and/or inhibited negative memory, possibly reflecting a contingent relationship to its incentive effects. When the role of individual differences was examined, relatively little influence was found in mediating the effects of alcohol on incidental memory. However, alcohol's effect on intentional memory was predicted by individual differences in response to some of alcohol's acute incentive effects. The studies demonstrate that alcohol's effects on memory are independent from, and can be combined with, its incentive effects. Further, consumption of alcohol may be influenced by separate effects on memory and incentive, and by their association.
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Daniels, Karen A. "Unconscious influences of memory : what we know about what we're unaware of." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/31045.
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Dade, Lauren A. "Brain structures subserving olfactory and visual learning and recognition : similarities and differences in nonverbal memory processing." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36904.
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The aim of these experiments was to investigate learning and memory extensively in two nonverbal domains (olfactory and visual), and to determine similarities and differences in the function of the neural substrates that subserve these modalities. Two complementary methodological approaches were taken: (1) examination of learning and retention in patients with resection from left (LR) or right (RR) temporal lobe, and (2) study of brain function via Positron Emission Tomography (PET) of healthy subjects during memory processing.Two parallel recognition tests were developed (one olfactory, one visual) that examined memory at three stages: following a single exposure to test stimuli, after four exposures, and following a 24hr delay interval. In the olfactory patient study, LR and RR groups performed significantly worse than the healthy control subjects, with no difference between the patient groups; thus suggesting a lack of hemispheric superiority for this task. The PET study of healthy individuals supported the bilateral participation of piriform cortex during olfactory recognition. The results from these two studies, along with findings from animal work, suggest that the piriform cortices may play a role in odor memory processing, not simply in perception.
On the face memory task, LR and RR patients showed different results. Only RR patients were impaired, while LR patients did not perform differently from controls. This unique face learning paradigm was sensitive to right temporal lobe damage, and correctly classified patients by side of resection with a sensitivity rate of 82% and specificity rate of 79%, suggesting its possible utility as a clinical tool. PET face memory findings indicated greater participation of fusiform regions during long-term recognition, and greater right prefrontal activity during short-term recognition, when these conditions are directly compared to each other.
Finally, PET was used to study the same healthy subjects performing parallel odor and face working-memory tasks, focusing on regions previously shown to be important for working memory. Results revealed similar regions of activation in dorsolateral prefrontal cortex in the two modalities. This indicates an overlap in the brain regions that process olfactory and visual information when the same cognitive manipulations are being carried out online.
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Robinson, Michael 1980. "Memory consolidation for a morphine conditioned place preference blocked by protein synthesis inhibition." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82415.
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The protein synthesis inhibitors cycloheximide and anisomycin were administered during training in an attempt to block the consolidation of the memory for a morphine conditioned place preference. The systemic injection of 2.5mg/kg of cycloheximide post-training failed to block consolidation, though there was a trend towards an attenuated preference, however cycloheximide produced a conditioned place aversion if paired with one compartment. To examine the effect of more complete protein synthesis inhibition and reduce the aversive effects, the less toxic protein synthesis inhibitor anisomycin was infused into the lateral ventricles of the brain either pre-, post- or 3 hours following training. Post-training infusions of anisomycin blocked the formation of a conditioned place preference, while pre-training and 3 hours post-training infusions showed no significant effect over two conditioning pairings. It was concluded that drug conditioning in the place preference paradigm requires protein synthesis for memory consolidation as do other learning paradigms.
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Stouffer, Eric M. "The neurobiology of latent learning in the rat using salt appetite and its dissociation from conditioning /." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102731.
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The brain areas required for latent learning in the rat are not currently understood. Previous tasks used to assess latent learning, defined as the acquisition of neutral information that does not immediately influence behavior, have shared characteristics that prevented their use to determine the neurobiology of latent learning. This thesis describes a new task called the Latent Cue Preference (LCP) task, derived from the Conditioned Cue Preference (CCP) task that has been successfully used to determine the brain areas required for conditioning in the rat and other animals. In the LCP task, water deprived rats alternately drink a salt solution in one distinctive compartment of a CCP box apparatus and water in the other compartment over 8 days (training trials). They are then given a choice between the two compartments with no solutions present (preference test). The results of the behavioral experiments showed that this training results in two parallel forms of learning: (1) latent learning of an association between salt and salt-paired compartment cues, and (2) conditioning to water-paired compartment cues. Latent learning itself involved two components: (1) the latent association between salt and salt-paired cues, and (2) motivational information about salt deprivation used to retrieve the latent association, and used to compete with the conditioning to water-paired cues. In addition, the findings showed that latent learning and conditioning involve different neural circuits. Latent learning required an intact cortical-to-hippocampus circuit via the entorhinal cortex, while conditioning required an intact subcortical-to-hippocampus circuit via the fimbria-fornix. The acquisition and storage of the latent association depended on an intact entorhinal cortex/dorsal hippocampus circuit, while the use of motivational information to retrieve the association recruited the ventral hippocampus. Conditioning, on the other hand, required an intact fimbria-fornix, lateral amygdala, and hippocampus. These findings provide new knowledge to the field of learning and memory research, and allowed an update of the current Multiple Memory Systems model.
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Wang, Szu-Han 1975. "Amnesia of reactivation, new learning and second learning." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103016.
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Memory refers to the retention of learned information or experiences in the brain. It is known that interference of certain brain functions immediately after training or memory reactivation can cause memory loss (i.e. amnesia). The post-training process is called consolidation and the post reactivation process is called reconsolidation. However, it remains unclear as to: (1) whether appetitive, goal-directed memories undergo reconsolidation, (2) whether overtrained memories undergo reconsolidation, (3) what the nature of amnesia is (i.e. whether it represents storage or retrieval impairment), (4) how to test the nature of amnesia, and (5) whether the brain uses the same mechanism for a new learning and from a second learning. This thesis, composed of five manuscripts, aims to answer these questions. In the first manuscript, the model of incentive learning of appetitive outcomes in instrumental conditioning was used. Protein synthesis inhibitor (PSI) was infused into lateral and basal amygdala (LBA) after the new incentive learning and after the reactivation of the memory. The results show that appetitive memories in controlling goal-directed behaviors underwent consolidation and reconsolidation in the LBA. In the second manuscript, rats were overtrained with auditory fear conditioning and received intra-LBA PSI infusions after memory reactivation. The results show that only old, but not recent, overtrained auditory fear memories underwent reconsolidation. This suggests overtraining sets a boundary condition on memory reconsolidation. Further results showed dorsal hippocampus and intra-LBA NR2B-subunit containing N-methyl-D-aspartic acid receptors (NMDAr) were involved in this boundary condition. In the third manuscript, the unresolved debate about the nature of amnesia was reviewed from a historical perspective and the suggestions on reconciling this issue are proposed. In the fourth manuscript, a new approach was used to test the nature of amnesia in contextual fear conditioning. Because NMDAr blockade impairs a new learning but not a second learning, it is predicted that if a memory is not stored then the second learning should be impaired by NMDAr blockade. The results suggest amnesia of contextual fear memory caused by intra-dorsal hippocampus (dH) PSI infusion represents a storage impairment which gives a different result from extinction induced irretrievability. In the fifth manuscript , the aim is to identify the brain mechanism for the second learning as the previous manuscript suggests it is different from the first learning mechanism. The results show that the first, but not the second learning required voltage-dependent calcium channels and activation in dH. The second learning was impaired by intra-dH or ventral hippocampus (vH) inactivation only when the protein synthesis in the other portion of hippocampus was blocked after training. This suggests while the first learning by default requires dH, the second learning can be acquired through a functional dH or vH. In summary, this thesis extends memory research from consolidating a new learning to characterizing the reconsolidation of appetitive and overtrained memory to consolidating a second learning which will lead to a more complete description of memory process.
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Macaulay, Dawn Leigh. "Mood dependent memory : extension and validation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25102.pdf.
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McDonald, Robert James. "Interactions among learning and memory systems : amygdala, dorsal striatum, and hippocampus." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28491.
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This series of experiments used the multiple learning and memory systems hypothesis of the mammalian nervous system to investigate the possibility that the amygdala, dorsal striatum, and hippocampal systems might, in certain situations, interact to produce behavior in the normal animal. Using variations of the conditioned-cue preference (CCP) task, evidence is presented showing that context-specific information acquired by the hippocampus interferes with acquisition of amygdala-based stimulus-reward learning. It was also demonstrated that there are amygdala-, dorsal striatum-, and hippocampus-based forms of place learning and that cue ambiguity and movement are important factors determining which of these learning and memory systems gain behavioral control in place learning situations. These findings provide evidence for interactions among learning and memory systems and implicate the amygdala and dorsal striatum in some types of non-hippocampal based place learning using distal cues.
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Packard, Mark G. "Differential roles of hippocampus and caudate nucleus in memory : selective mediation of "cognitive" and "associative" learning." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64070.
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White, Lynn H. "Task-specific effects of glucose and stress on memory." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ44628.pdf.
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Viaud, Marc. "Role of the dopaminergic and cholinergic systems of the rat neostriatum in learning and associative memory functions." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70244.
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The experiments in this thesis investigated the neuropharmacology of memory in the caudate nucleus, using the conditioned emotional response (CER) with visual and olfactory conditioned stimuli (CS).In experiment 1, post-training, intrastriatal microinjections of both amphetamine and LY 171555, but not SKF 38393: (1) into the posteroventral area improved memory of a visual, but not an olfactory, CER; (2) into the ventrolateral area improved memory of an olfactory, but not a visual, CER. In experiment 2, sulpiride, but not SCH 23390, blocked the memory improving effect of amphetamine. These findings are consistant with the hypothesis that dopamine D2 receptor stimulation mediates the memory enhancement effect of amphetamine in the neostriatum.
In three experiments on a visual CER, pre-training intrastriatal micro-injections of scopolamine impaired acquisition; post-training micro-injections improved consolidation; and pre-testing micro-injections impaired retrieval. These findings are consistant with the hypothesis that striatal muscarinic receptor stimulation mediates some aspects of acquisition and retrieval of sensory-motor memory, and that blockade of these receptors following training has an effect on memory consolidation similar to that of D2-receptor stimulation.
In experiment 6, destruction of the dopaminergic nigrostriatal neurons abolished the memory improving effect of intrastriatal post-training micro-injections of scopolamine and AFDX-384, a specific muscarinic M2 antagonist. These results suggest that the post-training memory improvement produced by muscarinic blockade may be mediated by an M2 receptor, known to be located on dopaminergic nigro-striatal terminals.
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Chai, Sin-Chee 1969. "Effects of lesions to learning and memory systems on the morphine conditioned cue preference." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27296.
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The present thesis investigates the effects of lesions to several hypothesized learning and memory systems on the morphine conditioned cue preference on the radial maze. Lesions of the structures thought to be centered to learning systems: the lateral nucleus of amygdala, fornix/fimbria, anterior dorsal striatum and posterior dorsal striatum, were made, In Experiment One, each structure was lesioned separately. Only lesions of the lateral nucleus of amygdala blocked morphine CCP learning. In Experiment Two, rats with combined lesions of fornix/fimbria and dorsal striatum, the lateral nucleus of amygdala and fornix/fimbria, as well as the lateral nucleus of amygdala and dorsal striatum were all impaired on morphine CCP. All of the rats with combined lesions were impaired in this CCP learning. These findings suggest that the lateral nucleus of amygdala is necessary for the morphine CCP. Participation of dorsal striatum or fornix/fimbria is also required. Some hypotheses about the interactions among the structures are discussed.
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Woolnough, Penny S. "Victimisation and eyewitness memory : exploring the effects of physiological and psychological factors." Thesis, University of St Andrews, 2002. http://hdl.handle.net/10023/13121.
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This thesis presents research designed to explore the role of physiological and psychological factors in mediating the effects of victimisation upon eyewitness memory. A tripartite model of arousal and memory is proposed encompassing physiological, psychological and motivational mechanisms. In order to investigate the potential role of these mechanisms, three laboratory based studies and one archival study are presented. The results of the laboratory studies suggest that physiological arousal may not influence eyewitness memory. In contrast, whilst direct support for an influence of psychological arousal is not provided, the possibility that psychological arousal may be an important factor cannot readily be dismissed. From a methodological perspective, contrary to existing laboratory-based research concerning visually-induced arousal, the results of the laboratory studies suggest that personal involvement may be an important factor influencing memory. Furthermore, the third laboratory study found that, differences in memory for emotional and neutral material may be a function of inherent differences between the material rather than an influence of arousal. Finally, in order to compare and contrast laboratory based research with the performance of real witnesses, a field based study utilising closed-circuit television to assess eyewitness accuracy for action details was conducted. In line with Studies One and Two, victims and bystanders were not found to differ in their memory performance. This study provides direct support for existing field and archival research suggesting that real victims and bystanders tend to be highly accurate in their eyewitness accounts. Taken together, the results of the research presented in this thesis suggest that whilst physiological arousal may not be an important factor influencing eyewitness memory, psychological and motivational influences may be important when witnesses are personally involved with the target incident.
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Lalonde, Jasmin. "Task-dependent transfer of perceptual to memory representations during delayed spatial frequency discrimination." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33911.
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Discrimination thresholds were obtained during a delayed spatial frequency discrimination task. In Experiment 1, we found that presentation of a mask 3 s before onset of a reference Gabor patch caused selective interference in a subsequent discrimination task. However, a 10 s interval abolished this masking effect. In Experiment 2, the mask was associated with a second spatial frequency discrimination task so that a representation of the mask had to be coded into short-term perceptual memory. The presence of this second discrimination task now caused similar interference effects on the primary discrimination task at both the 3 s and 10 s ISI conditions. The different results from these two experiments are best explained by a two-step perceptual memory mechanism. The results also provide further insight into the conditions under which stimulus representations are shared between the perceptual and memory domains.
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Sziklas, Viviane. "Behavioural investigation of the mammillary region in the rat." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70274.
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The experiments reported in the present dissertation investigated the contribution of the mammillary region to several classes of learning and memory: spatial memory, nonspatial memory, and conditioned aversion learning. It was demonstrated that such lesions impair performance on tasks that require memory for spatial information but that the deficit depends on both the amount of damage within the region as well as the degree of difficulty of the task. A dissociation in the effect of such lesions on performance of comparable spatial and nonspatial memory tasks was shown. In contrast to the severe deficits observed on spatial memory tasks, the acquisition and retention of a complex nonspatial memory task was not impaired after extensive damage to the mammillary region. Such lesions also did not impair performance on two conditioned aversion tasks. These experiments suggest that the mammillary region may be selectively involved in spatial learning and memory. The relevance of these findings to Korsakoff's syndrome is discussed.
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Thaiss, Laila Maria. "A comparison of the role of the frontal cortex and the anterior temporal lobe in source memory and in the accurate retrieval of episodic information /." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38424.
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It has been argued that patients with frontal lobe lesions are impaired in temporal context memory and, more generally, in retrieving the source of one's knowledge or ideas. Furthermore, it has been speculated that a failure to retrieve source information may result in an increased susceptibility to distortions of episodic memories in patients with frontal lobe lesions. The precise role of the frontal cortex, however, in source or episodic retrieval is not clear. Does this region of cortex play a primary role or a secondary, executive role in the processing of such memories? Studies of patients with temporal lobe lesions have also shown impairments in episodic memory, including difficulties in the retrieval of source information. An important issue, therefore, is whether these two brain regions make different contributions to the processing of source information and to the retrieval of episodic memories.In the present experiments, patients with unilateral excisions restricted to frontal cortex or to the anterior temporal lobe were compared on various tasks examining source memory performance and the accurate retrieval of episodic information. The results of these studies failed to support the general contention that patients with frontal cortex excisions have source (or temporal context) memory impairments. Instead, differences between these patients and normal control subjects appeared to be contingent on whether strategic organizational or control processes were necessary for efficient processing of episodic information. The memory of patients with left temporal lobe excisions, on the other hand, was significantly impaired for both content and source information in most tasks. Furthermore, these subjects showed high rates of inaccuracies and distortions of memory. The false memories of this patient group were attributed to a combination of their poor memory for the specific items of the task and their over-reliance on semantic "gist" or on inferential knowledge about the events. Patients with right temporal lobe excisions were generally less severely impaired on the verbal memory tasks compared with those with left-sided lesions, but were impaired in their memory for the contextual aspects of an event.
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Albanese, Marie-Claire. "FMRI evidence of memory representations of somatosensory stimuli in the human brain." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102949.
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Distinct brain regions process innocuous vibration and cutaneous heat pain. The role of these areas in the perception of pain is still a matter of debate; and the role of these areas in the mediation of memory of somatosensory stimuli is uncertain and has not been studied with brain imaging in healthy human volunteers. All experiments described here, involved an experimental design, which included a delayed-discrimination paradigm and functional magnetic resonance imaging (fMRI). In manuscript #1, we aimed at unraveling the cerebral correlates of attention and spatial localization of innocuous vibrotactile stimuli applied to the right volar surface of the forearm. In this study, we report that increased degrees of attention to the vibrotactile stimuli were associated with heightened levels of activation in several brain areas. In manuscript #2, we investigated the short-term memory for sensory aspects (intensity and location) of cutaneous heat pain delivered to two areas (thenar and hypothenar eminences) of the palm of the right hand. In this experiment, the memory and control trials were presented in blocks, whereby the subjects could predict what trials were going to follow. This study revealed that the presentation of painful stimuli evoked activation in different brain regions than those activated during the online maintenance (interstimulus interval or ISI) of the intensity and spatial features of those stimuli; a process, which I will refer to short-term memory. In manuscript #3, we investigated again short-term memory for sensory aspects of heat pain (as in manuscript #2), but in this case, the memory and control trials were presented in a randomized order. In this study, we found that the perception and short-term memory of pain were processed by a comparable network of areas. The predictability of the memory and control trials may have contributed to these findings.La vibration inoffensive ainsi que la chaleur douloureuse cutanée sont traitées pardifférentes régions du cerveau. Le rôle de ces régions dans la perception de la douleurest controversé; et le rôle de ces régions dans la mémoire des stimuli somatosensorielsest incertain et n'a jamais encore été étudié en imagerie cérébrale chez des sujetshumains sains. Le design expérimental de toutes les études décrites ici comprenait unparadigme de 'delayed-discrimination' et l'imagerie par résonance magnétiquefonctionnelle (IRMf). L'étude #1 visait à élucider les corrélats cérébraux de l'attention etde la localisation spatiale des stimuli vibrotactiles inoffensifs présentés à la faceantérieure de l'avant-bras droit. Dans cette étude, nous avons trouvé que des degrésélevés d'attention portée aux stimuli vibrotactiles étaient associés à des niveaux accrusd'activation dans plusieurs zones du cerveau. Dans l'étude #2, nous avons enquêté surla mémoire à court-terme des caractéristiques sensorielles (intensité et emplacement)de la chaleur douloureuse cutanée présentée à deux endroits (éminences thénar ethypothénar) de la paume de la main droite. Dans cette étude, les essais mémoire etcontrôle étaient présentés en bloc, ou de sorte que les participants pouvaient prévoir dequel type serait le prochain essai. Cette étude a révélé que la présentation des stimulidouloureux a évoqué une activation de différentes régions cérébrales que celles quiétaient activées lors de la rétention de l'intensité et de l'emplacement des stimulationsdurant l'intervalle inter-stimuli (liS); un processus que je qualifierai de mémoire à courtterme.Dans l'étude #3, nous avons également enquêté sur la 'mémoire à court-termedes aspects sensoriels de la chaleur douloureuse (tout comme dans l'étude #2), maisdans ce cas, les essais mémoire et contrôle étaient présentés de façon aléatoire. Danscette étude, nous avons trouvé que la perception de la douleur ainsi que la mémoire àcourt-terme de la douleur étaient traitées par un réseau de régions semblable. Laprévisibilité des essais mémoire et contrôle peut avoir contribué à ce résultat.
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Phillips, Susana M. (Susana Maria). "The relationship between sex steroid levels and memory functions in women." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28513.
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Memory function was examined in association with sex hormone levels in women. The results of the first study suggest that self-reports of memory problems were especially prevalent among women attending a menopause clinic compared to a nonpatient sample. In the following investigation, women given placebo after undergoing a bilateral oophorectomy showed decreases in memory performance, specifically on a paired-associate learning task, coincident with declines in estrogen levels. Significant improvements were found in estrogen-treated women pre- to postoperatively in the immediate recall of paragraphs, in association with supraphysiological estrogen levels. A final study on naturally-cycling women found a decline in visual memory performance during the menstrual compared to the luteal phase of the cycle. Visual memory scores were positively correlated with progesterone levels whereas paired-associate recall scores were positively associated with estradiol levels during the luteal phase. These results suggest that certain aspects of memory covary with changes in sex steroid levels in some women.
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Farrimond, Samantha, and n/a. "The effects of aging on remembering intentions : the virtual street task." University of Otago. Department of Psychology, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070322.142811.
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In everyday life memory is commonly used in the completion of future intentions, such as remembering to attend a meeting or remembering to make a purchase at a particular time or place. The ability to remember to complete future intentions plays an important role in older adults maintaining independent living within the community (Cherry & LeCompte, 1999). The studies presented in this thesis evolved out of the lack of current understanding about which component processes involved in remembering future intentions are most susceptible to the effects of aging. In order to investigate these processes, a computer-based analogue of a real-life task was developed (the Virtual Street) that enabled participants to complete a series of intentions (shopping errands) during a simulated visit to a shopping centre.
There were two main objectives of this thesis. The first objective was to examine whether the Virtual Street shopping task was appropriate for assessing older and younger adults ability to remember to complete delayed intentions and whether the task had better ecological and face validity than current assessment measures. The second objective was to identify the cognitive processes involved in the task that were vulnerable to the effects of aging, and whether the process of recognising the cues or the memory search of the intention content would be affected. In order to examine these cognitive processes, various factors were manipulated in ways designed to be analogous to real-world situations, which were hypothesized to be sensitive to the effects of aging. These factors include: a change in the location where an intention can be realised (Study 1), the opportunity to learn the intentions (Study 2), the familiarity of the shopping environment (Study 3), and the presence of distractions (Study 4).
Overall, the results from the four studies demonstrated that older adults have difficulty remembering delayed intentions, even when the test uses naturalistic stimuli, the tasks are familiar, and they are able to move at their own pace. Furthermore, the results from Study 2 demonstrated that the memory search component but not cue detection was affected in older persons when they were given fewer trials to learn the shopping errands, possibly due to the accessibility of the cue-intention associations may be impaired in older adults. There was no age specific effect on cue detection or memory search in either an unfamiliar street environment (Study 3) or one with increased levels of irrelevant auditory and visual noise (distraction condition, Study 4). In the interruption condition of Study 4, however, cue detection but not memory search was disproportionately affected in older adults after filled interruptions, suggesting that the capacity for self-initiated reinstatement of working memory is reduced in old age.
In general, the Virtual Street task was to be a practical means of examining younger and older adults ability to remember to complete delayed intentions. The Virtual Street task also provided an opportunity for behavioural observation of real-life skills and cognitive abilities, within a controlled context. It is hoped that the Virtual Street shopping task will continue to be developed into an ecologically valid measure of assessing older adults memory functioning.
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Tomie, Jo-Anne B., and University of Lethbridge Faculty of Arts and Science. "Cognitive behavior of rats with thalamic lesions." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 1994, 1994. http://hdl.handle.net/10133/60.
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The objective of this thesis was to test the idea that medial thalamic nuclei are part of a "memory circuit" in the brain. Rats received lesions of the anterior (ANT) or medial dorsal (MD) thalamic nuclei and were tested on two spatial tasks, a nonspatial configural task, and spontaneous and amphetamine-induced acitivity. The thalamic rats were impaired on the spatial and conifural tasks, ans some of the thalamic groups were slightly hyperactive after administration of amphertamine. The deficits were not large and could not be unequivocally attributed to the ANT or MD damage. The results question the role of the ANT or MD in the behaviors studied. It is suggested that the deficits obtained after thalamic damage may be nonspecific and it is concluded that the results do not support the notion that thalamic structures have a primary role in memory.xi, 187 leaves : ill., plates ; 29 cm.
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Roberts, Michael J. 1973. "NMDA receptor activity is necessary for long-term memory in the non-spatial, hippocampal-dependent, social transmission of food preference task." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31532.
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Memory of some forms requires the hippocampus, a brain structure in the medial temporal lobe that reveals remarkable synaptic plasticity. Most synapses in the hippocampus require NMDA-receptors for the induction of this plasticity. Memories that require the hippocampus may also require NMDA-receptor mediated plasticity. This thesis tested the involvement of NMDA receptor activity in memory for a non-spatial, social learning task that requires the hippocampus: the social transmission of food preference, NMDA receptor antagonist (CPP) injected systemically 55 minutes prior to training impaired performance 72 hours later, but not 48 hours, 24 hours, or 15 minutes later. NMDA receptor antagonist (AP-5) injected into the dorsal hippocampus 30 minutes prior to training also impaired performance at the 72-hour delay. Injections of CPP at 10 minutes or 24 hours post-training had no effect on performance. These results suggest that hippocampal NMDA receptor activity is necessary for stable learning of the non-spatial social transmission of food preference.
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Fisher, Kim Noël. "Behavioural and physiological effects of two aniracetam analogues." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22585.
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The behavioural and electrophysiological consequences of two newly developed aniracetam analogues were investigated in male Long-Evans rats. Results indicate that an intraperitoneal (i.p.) injection of LD38.2 significantly improved retention in a two odour olfactory discrimination task. However, three different dosages of LN1 did not facilitate memory in the task. In rats with chronically implanted electrodes, both compounds rapidly crossed the blood brain barrier (BBB) after an i.p. injection and influenced several parameters of the field excitatory postsynaptic potential (EPSP) in the CA1 and dentate gyrus regions of the hippocampus. The enhancement of the field EPSP following LD38.2 administration may be related to the drug's ability to facilitate memory in the olfactory discrimination task. Compounds, like LD38.2, that enhance both hippocampal transmission and performance in learning/memory tasks in laboratory rodents may have implications for the treatment of clinical memory disorders.
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Patai, Eva Zita. "How memories facilitate perception in the human brain." Thesis, University of Oxford, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572889.
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thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at the University of Oxford Approximate Word Count: 50,000 After literary scholars, the group of people who most likely cite Marcel Proust are the niche group of psychologists and neuroscientists researching the topic of memory. The incident of the madeleine and Proust's vibrant re-experiencing of 'times past' highlights how important contextual associations are in our lives. The memories we form are often rich in contextual detail, and it is this type of memory which I aim to explore in this thesis. Specifically, I show how memories of contextual nature are formed, and used to guide behaviour. In the General Introduction (Chapter 1), I review the background literature of attention, and the different sources of information that guide it, as well as how contextual information -the associations between iterns-, specifically in natural scenes, can serve as such a source. Next, I describe in detail the literature to date on memory-based signals for attentional guidance. The next chapter summarizes the methodological approaches used in this thesis (Chapter 2). In Chapter 3, I show that long-term memory can optimize perception in complex natural scenes by modulating preparatory attention as well as target processing, using electroencephalography (EEG). In Chapter 4, exploiting the high temporal and spatial resolution of magnetoencephalography (MEG), I explore the neurophysiological markers of encoding, while participants learned contextual associations. In the final experimental chapter (Chapter 5), in a series of experiments I test the low-level mechanisms through which the long-term memory-bias in attentional guidance comes about. In the General Discussion (Chapter 6), I summarize my Findings and incorporate them into the existing literature, and propose outstanding questions.
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Chai, Sin-Chee 1969. "The functions of amygdala and hippocampus in conditioned cue preference learning /." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38470.
Full textAbstract:
The experiments in this thesis examined the roles of stimulus configuration on conditioned cue preference (CCP) learning by asking what information is processed and by which neural substrates. Results from Experiments 1 and 2 showed that lesions of the lateral nucleus of the amygdala (LNA) but not of fimbria-fornix (FF) impaired CCP learning when the cues paired with food during training were distinct from those not paired with food in either of two different apparatuses. In Experiments 3 and 4 LNA lesions increased the size of the CCP when the cues paired with food and no food were ambiguous in two different apparatuses. Learning the ambiguous cue CCP required at least one session of unreinforced pre-exposure to the cues and was eliminated by FF lesions. In the last series of experiments, a latent learning effect of unreinforced pre-exposure on ambiguous cue CCP learning on the radial maze was found in normal animals that received at least 3 sessions of unreinforced pre-exposure. FF lesions made before, but not after, pre-exposure eliminated the latent learning effect. Hippocampus lesions made either before or after pre-exposure eliminated the CCP learning. Taken together, the results are consistent with the hypothesis that distinct cue CCP learning is based on conditioned approach responses to cues paired with food, mediated by a neural system that includes the LNA. The results also suggest that ambiguous cue CCP learning takes place in two phases. First spatial learning occurs during unreinforced pre-exposure, a process that requires an intact FF. Subsequently, information about the location of the reinforcer is added to the spatial information during the reinforced training trials by a process of "reconsolidation". An intact hippocampus is required for this process. The implications of these results and interpretations for latent learning and latent inhibition are considered.
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Epp, Jonathon, and University of Lethbridge Faculty of Arts and Science. "The hippocampus, retrograde amnesia, and memory deconsolidation." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2005, 2005. http://hdl.handle.net/10133/219.
Full textAbstract:
There are numerous clinical and experimental accounts of retrograde and anterograde amnesia resulting from damage to the hippocampus (HPC). Several theories on the HPC hold that only certain types of recent memories should be affected by HPC damage. These theories do not accurately predict the circumstances within which memories are vulnerable to HPC damage. Here I show the HPC plays a role in the formation and storage of a wider range of memories than is posited in contemporary theories. I will demonstrate that an important factor in elciting retrograde amnesia is the number of similar learning episodes. Exposure to multiple problems in the same task context leads to retorgrade amnesia that is not observed when only one problem is learned under otherwise identical parameters. When multiple discriminations are learned, the output of the HPC blocks recall from and future use of the extra-HPC memory system.x, 78 leaves : ill. ; 29 cm.
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Mitchell, Damon John, and n/a. "Phase-reset and effects of ethanol in non-verbal working memory tasks : is there a homologue of hippocampal theta in the human EEG." University of Otago. Department of Psychology, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090309.150949.
Full textAbstract:
Anxiety disorder is prevalent and costly. But its diagnosis is underdeveloped and treatment ad hoc. This could be corrected if the neural mechanisms of anxiety were known. All anxiolytic medications produce a decrease in rodent hippocampal theta rhythm - so hippocampal theta could underlie some types of anxiety. But, a review (Chapter 2) showed that ethanol and other anxiolytics increase FM-theta in the human scalp EEG and have other properties unlike hippocampal theta. The experiments in this thesis, therefore, tested for other potential homologues (Chapter 3) of hippocampal theta in the human EEG.
The phase of hippocampal theta activity is reset in a working memory task and not an equivalent reference memory task in rats. Furthermore, low doses ethanol increases and high dose ethanol (and other anxiolytics) decrease theta activity. So, EEG was recorded from 15 scalp sites while participants performed non-verbal working memory and reference memory tasks before and after ethanol administration and assessed for the presence of phase-reset and ethanol-related changes in 5-7Hz and 8-11Hz spectral power (chapter 4 and 5).
There was little general evidence for stimulus-induced phase-resetting of the ongoing EEG activity (Chapter 6). Increased post-stimulus synchronization in the theta frequency range was accompanied by increases in post-stimulus spectral power - suggesting that the synchronised activity was evoked rather than reset.
Across 3 experiments (Chapter 7), low dose ethanol (54.5-146.6[mu]g/l) increased 5-7Hz theta, while the highest dose (307[mu]g/l) reduced task-related-increases in 5-7Hz activity. These effects were noted across electrode locations including frontal-midline sites and particularly at the beginning of the delay period. The suppression of 5-7Hz activity also coincided with an impairment in working memory performance. The dose-response curve for 5-7Hz theta was as predicted from rat hippocampal work. This particular component, linked to high working memory load or task difficulty, is a potential of homologue hippocampal theta. A clear decrease in theta with high dose ethanol, of this type, has not been reported previously.
Activity in the 8-11Hz range typically increased with all doses of ethanol. It is clearly not a homologue of hippocampal theta. This is consistent with previous reports of increased alpha with high doses of ethanol - although these have been accompanied by increased, not decreased, theta.
There is a potential homologue of hippocampal theta that can be detected in the human EEG (chapter 8); but the observed changes in 5-7Hz activity cannot be localised and may not be related to the hippocampus. It is clear there is more than one type of theta within the human EEG - with opposing sensitivities to ethanol. Critically, these types were detected at a single site and apparently in phase with one another. The current data, together with the previous literature, suggest that theta can be generated concurrently in distinct networks that, under specific task demands, can become coherent and so produce synchonised activity. Future studies need to test higher doses of ethanol and other anxiolytics and use different experimental paradigms to further differentiate the theta systems in the human EEG. Human EEG could be useful for differentiating sub-types of anxiety, and the choice and effectiveness of interventions delivered.
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Spanswick, Simon, and University of Lethbridge Faculty of Arts and Science. "A behavioural analysis of visual pattern separation ability by rats : effects of damage to the hippocampus." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2005, 2005. http://hdl.handle.net/10133/236.
Full textAbstract:
Different events usually contain similar elements that can contribute to interference during memory encoding and retrieval. The hippocampus (HPC), a structure that is critically involved in some forms of memory, has been hypothesized to reduce interference between memories with overlapping content, thus facilitating correct recall. Pattern separation is one hypothetical process whereby input ambiguity is reduced. Here we test the hypothesis that the HPC and/or dentate gyrus (DG) are important for pattern separation by measuring performance by rats with damage in tasks that require discrimination between visual stimuli that share systematically varying numbers of common elements. Rats with HPC damage were slower to resolve discriminations with minimal degrees of overlap. Lesions of the DG did not affect the ability of rats to deal with overlap, suggesting a dissociation between the HPC and DG. Our results provide partial support for the idea that the HPC contributes to the pattern separation process.ix, 84 leaves : ill. ; 29 cm.
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Urbain, Charline. "Learning and memory consolidation processes in children and adults: a neurophysiological and neuropsychological investigation." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209571.
Full textAbstract:
Learning and memory consolidation processes in children and adults: aneurophysiological and neuropsychological investigation.
Sleep is a complex and active state of the brain, associated with essential functional changes
[1]. Accumulated evidence in the adult population indicates that sleep participates in the
consolidation of declarative (i.e. memory for facts and episodes) and procedural (i.e. skills
and habits) memory, allowing novel information to be integrated for the long term in cerebral
networks [2]. Whether sleep supports memory consolidation in children likewise and to the
same extent than in adults remains disputed. In this framework, I have developed
experiments aimed at investigating sleep-dependent consolidation processes both in children
and adults, using behavioral and neurophysiological techniques (magneto-encephalography
[MEG]; electro-encephalography [EEG]; functional magnetic resonance imaging [fMRI]). To
sum up, researches conducted during my PhD thesis have contributed to start unraveling
neurophysiological mechanisms participating in sleep-dependent consolidation processes.
On the one hand, I report that despite a lack of detectable behavioral differences, posttraining
sleep plays a role in reshaping the cerebral networks subtending implicit motor
sequence learning in adults [3]. I also showed using a motor adaptation task [4] that sleep
contributes to the consolidation of procedural memory in children [5]. On the other hand, I
have evidenced neuromagnetic correlates of learning novel semantic representations in
children [6-7], and is currently finalizing the analysis of the effect of a post-training nap on the
consolidation of these representations. Finally, I showed in epileptic children that interictal
epileptic discharges (IED) during sleep impairs declarative memory consolidation processes
[8-9], and that this phenomenon is reversible upon pharmacological treatment suppressing
IED. Altogether, these findings advocate the need to explore further memory consolidation
and its neurophysiological basis in children, both healthy and suffering from various brain
pathologies [10].
[1] Urbain C. Peigneux, P. & Schmitz R. Sleep and the Brain. (to appear). In The Oxford Handbook of
Sleep and Sleep Disorders. C. M. Morin and C. A. Espie (Eds.). Oxford University Press, Oxford, NY.
[2] Peigneux P. Schmitz R. & Urbain C. Sleep and Forgetting. In Forgetting. S. Della Sala (Ed.).
Psychology Press, Hove, UK. 2010. (pp. 165-184).
[3] Urbain C. Schmitz R. Schmidt C. Cleeremans A. Van Bogaert P. Maquet P. and Peigneux P.
(submitted). Neuroanatomical Sleep-Dependent Processing in the Probabilistic Serial Reaction Time
Task.
[4] Huber, R. Ghilardi, M.F. Massimini, M. And Tononi, G. Local sleep and learning. Nature, 2004,
430, 78-84.
[5] Urbain C. Houyoux E. Albouy G. Peigneux P. (in preparation). Sleep-dependent consolidation of
procedural learning in children.
[6] Urbain C. Schmitz R. Op De Beeck M. Bourguignon M. Galer S. X. De Tiège, Van Bogaert P.
and Peigneux P. (in preparation). How learning new meanings about novel objects modulates cerebral
activity in children: A MEG Study.
[7] Urbain C. Schmitz R. Bourguignon M. Op De Beeck M. Galer S, De Tiège X. Van Bogaert P.
Peigneux P. (2011). Learning and Fast-Mapping Meanings to Novel Object in Children: A MEG Study.
17th Annual Meeting of the Organization for Human Brain Mapping [HBM], 26-30 June 2011, Québec
City, Canada
[8] Urbain C. et al. Is sleep-related consolidation impaired in focal idiopathic epilepsies of childhood?
A pilot study, Epilepsy and Behavior, 2011, 22(2), 380-384.
[9] Van Bogaert P. Urbain C. Galer S. Ligot N. Peigneux P. and De Tiège X. Impact of focal
interictal epileptiform discharges on behaviour and cognition in children. Neurophysiologie
Clinique/Clinical Neurophysiology, 2012, 42(1–2), 53-58.
Doctorat en Sciences Psychologiques et de l'éducation
info:eu-repo/semantics/nonPublished
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Taylor, Chanel Jayne, and n/a. "Secreted amyloid precursor protein-alpha modulates hippocampal long-term potentiation, in vivo." University of Otago. Department of Psychology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081217.144344.
Full textAbstract:
Alzheimer�s disease (AD) is a neurodegenerative disorder, charaeterised by progressive loss of memory. It is important to understand what factors initiate the onset of AD so that effective therapeutic treatments can be developed to target the precise mechanisms that initiate this disease. Currently, synaptic dysfunction is widely believed to be the first significant alteration preceding the onset of AD, and is thought to be initiated by an intracellular accumulation of amyloid-β (Aβ), or a free radical-induced increase of oxidative stress. As Aβ levels rise during the onset of AD, a concomitant reduction of secreted amyloid precursor protein-α (sAPPα) is observed, as the two proteins exist in equilibrium. Intriguingly, the neuroprotective and neurotrophic properties of sAPPα indicate that it is intimately involved in the physiological pathways of the major hypotheses for the cause of AD, and may also be involved in the mechanisms that underlie learning and memory. Therefore, it is possible that during the onset of AD, the decrease of sAPPα may contribute to synaptic dysfunction by disrupting the mechanisms of synaptic plasticity.
Long-term potentiation (LTP) is the leading experimental model for investigating the neural substrate of memory formation, and describes the molecular mechanisms that underlie an increase in the strength of synaptic transmission. The role sAPPα may play in the induction and maintenance of LTP has not previously been addressed in vivo. Therefore, the aim of this thesis was to investigate whether sAPPα affects the induction of LTP in the hippocampus of the anaesthetised rat. The present findings are the first to suggest that sAPPα may modulate the induction of LTP in vivo. Decreasing the function of endogenous sAPPα (with sAPPα-binding antibodies and a pharmacological inhibition of α-secretase) significantly reduced the magnitude of LTP induced in the dentate gyrus. Therefore, the reduction of sAPPα during AD is likely to have a detrimental impact on the mechanisms of synaptic plasticity, and by extension, learning and memory. The present investigation has also found that the application of recombinant, purified sAPPα to the rat hippocampus has an �inverted U-shaped� dose-response effect on the magnitude of LTP. Low concentrations of sAPPα significantly enhanced LTP, supporting previous findings that exogenous sAPPα can facilitate in vitro LTP and enhance memory performance in animals. On the other hand, comparatively high concentrations of sAPPα significantly decreased the magnitude of LTP. This observation is also consistent with previous findings, in which high concentrations of sAPPα have been shown to be less synaptogenic and memory enhancing than lower doses. These results are the first to suggest that sAPPα modulates in vivo synaptic plasticity, and have important implications for the development of strategies to treat AD.
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Sparks, Fraser T. "Interactions of the hippocampus and non-hippocampal long-term memory systems during learning, remembering, and over time." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience, c2012, 2012. http://hdl.handle.net/10133/3116.
Full textAbstract:
The hippocampus and non-hippocampal long-term memory systems each have the capacity
to learn and express contextual fear memory. How these systems interact during learning
and remembering revolves around hippocampal mediated interference, where the hippocampus
dominates for both the acquisition and expression of long-term memory. Hippocampal
interference during learning can be overcome by modifying learning parameters
such that learning is distributed across multiple independent sessions. The standard view of
the role of the hippocampus in long-term memory retrieval is that it is temporally limited,
where recently acquired memory is dependent on hippocampal function though as a memory
ages, dependency is transferred to other memory systems by a process called systems
consolidation. Distributed training demonstrates that learning parameters create a memory
that is resistant to hippocampal damage. We find little evidence to support temporally based
systems consolidation, and present data that supports the view that if the hippocampus is
initially involved in learning a memory, it will always be necessary for accurate retrieval
of that memory. A critical assessment of the rat literature revealed that initial memory
strength, and/or lesion techniques might be responsible for the few studies that report temporally
graded retrograde amnesia using contextual fear conditioning. Our experiments
designed to directly test these possibilities resulted in flat gradients, providing further evidence
that the hippocampus plays a permanent role in long-term memory retrieval. We
propose and assess alternatives to the standard model and conclude that a dual store model
is most parsimonious within the presented experiments and related literature. Interactions
of the hippocampus and non-hippocampal systems take place at the time of learning and
remembering, and are persistent over time.xvi, 161 leaves : ill. (some col.) ; 29 cm
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Sivakumaran, Magali H. "Empirical and methodological investigations into novelty and familiarity as separate processes that support recognition memory in rats and humans." Thesis, University of St Andrews, 2018. http://hdl.handle.net/10023/13785.
Full textAbstract:
There is a prevalent assumption in the recognition memory literature that the terms “novelty” and “familiarity” are words ascribed to differing extremities of a single memory strength continuum. The aim of the current thesis was to integrate experimental methodologies across human and rodents to further investigate novelty processing at both a cognitive and neural level, and assess whether it is dissociable from familiarity processing. This dissociation was questioned at a cognitive level in human participants in Experiments 1 to 3 and at a neural level in rats in Experiment 4 and 5. Participants were found to differentially assess novelty and familiarity when making confidence judgements about the mnemonic status of an item (Experiment 1). Additionally, novelty and familiarity processing for questioned items were found to be dissimilarly affected by the presence of a concurrent item of varying mnemonic statuses (Experiment 2 and 3). The presence of a concurrent familiar item did not impact novelty processing in the perirhinal cortex (Experiment 4 and 5), yet disrupted the neural networks established to be differentially engaged by novelty and familiarity (Experiment 5). These findings challenge the assumption that the terms “novelty” and “familiarity” relate to a single recognition memory process. Finally, to allow integration of the findings from the human and rodent experiments, the relationship between measures or recognition memory obtained from spontaneous object recognition (SOR) task in rats and recognition memory measures estimated from signal-detection based models of recognition memory in humans was investigated (Experiment 6 and 7). This revealed that novelty preference in the SOR was positively correlated to measures of recognition memory sensitivity, but not bias. Thus, this thesis argues for the future inclusion of a novelty as a dissociable process from familiarity in our understanding of recognition memory, and for the integrations of experimental methodologies used to test recognition memory across species.
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Hulme, Sarah R., and n/a. "Heterosynaptic metaplasticity in area CA1 of the hippocampus." University of Otago. Department of Psychology, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090818.161738.
Full textAbstract:
Long-term potentiation (LTP) is an activity-dependent increase in the efficacy of synaptic transmission. In concert with long-term depression (LTD), this synaptic plasticity likely underlies some types of learning and memory. It has been suggested that for LTP/LTD to act as effective memory storage mechanisms, homeostatic regulation is required. This need for plasticity regulation is incorporated into the Bienenstock, Cooper and Munro (BCM) theory by a threshold determining LTD/LTP induction, which is altered by the previous history of activity (Bienenstock et al., 1982). The present work aimed to test key predictions of the BCM model. This was done using field and intracellular recordings in area CA1 of hippocampal slices from young, adult male Sprague-Dawley rats. The first prediction tested was that following a strong, high-frequency priming stimulation all synapses on primed cells will show inhibition of subsequent LTP and facilitation of LTD induction (heterosynaptic metaplasticity). This was confirmed using two independent Schaffer collateral pathways to the same CA1 pyramidal cells. Following priming stimulation to one pathway, LTP induction was heterosynaptically inhibited and LTD facilitated. To more fully investigate whether all synapses show metaplastic changes, the priming stimulation was given in a different dendritic compartment, in stratum oriens, prior to LTP induction in stratum radiatum. This experiment supported the conclusion that all synapses show inhibited LTP following priming. A second prediction of the BCM model is that metaplasticity induction is determined by the history of cell firing. To investigate this, cells were hyperpolarized during priming to completely prevent somatic action potentials. Under these conditions inhibitory priming of LTP was still observed, and thus somatic action potentials are not critical for the induction of the effect. The next aim was to determine the mechanism underlying heterosynaptic metaplasticity. One way in which plasticity induction can be altered is through changes in gamma-aminobutyric acid (GABA)-mediated inhibition of pyramidal cells. For this reason, it was tested whether blocking all GABAergic inhibition, for the duration of the experiment, would prevent priming of LTP. However, priming inhibited subsequent LTP and it was concluded that GABAergic changes do not underlie either the induction, or expression, of the metaplastic state. Proposed revisions to the BCM model predict that postsynaptic elevations in intracellular Ca�⁺ determine the induction of metaplasticity. There are many potential sources for postsynaptic Ca�⁺ elevations, including entry through N-methyl-D-asparate receptors (NMDARs) or voltage-dependent calcium channels (VDCCs), or release from intracellular stores. Results of the present work demonstrate that the inhibition of LTP is dependent on the release of Ca�⁺ from intracellular stores during priming; however this release is not triggered by Ca�⁺ entry through NMDARs or VDCCs, or via activation of metabotropic glutamate receptors. Overall, the present results show that, in accordance with the BCM model, a high level of prior activity induces a cell-wide metaplastic state, such that LTD is facilitated and LTP is inhibited. In contrast to predictions of the BCM model, this is not mediated by cell-firing during priming. Instead the release of Ca�⁺ from intracellular stores is critical for induction of the metaplastic state.
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Bennett, Elizabeth G. "Visual dysfunction : a contributing factor in memory deficits, and therefore learning difficulties?" Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2007. https://ro.ecu.edu.au/theses/266.
Full textAbstract:
This thesis is based on Educational Therapy (ET) practice which has found eye muscle imbalance is a key factor to be addressed in management of learning difficulties (LD). This level of oculo-motor (o-m) function is a 'hidden' handicap as individuals are unaware of the problem; it is not routinely tested; and is not generally included in learning difficulties research. O-m function is omitted in standard paediatric optometry tests, and in school vision screening. Eye exercises increase the range of binocular fields of vision by employing stereopsis glasses and red/green slides. Central vision loss was uncovered when students reported words, seen by only the right eye, "disappear" or "switch on and off". When the left eye was covered, right eye vision returned but was lost again with binocular vision, even though larger shapes on the screen remained complete. In effect, global vision was unaffected while right eye central (foveal) vision was suppressed. This is considered significant because students attending ET have learning difficulties with phonemic memory, spelling and reading deficits, which are predominantly left hemisphere processes. The aim of this three-part study, consisting of School Survey, ET Intervention study and Case studies, was to: a) determine whether o-m dysfunction was found in a girls' school population and/or was associated with LD; b) set up an Intervention study to explore the effects of vision training on the outcomes of a subsequent week-long word-skills programme in the ET practice. Two case studies we're also examined, that of matched senior school boys whose outcomes were significantly different; and c) examine more closely the common pattern of muscle imbalance in two case studies of current junior school students. This tested the therapy assumption that mal-adaptive sensory feedback was contributing to o-m dysfunction. This notion is based on the Luria (1973) Model of Levels of Neural Function which provides the framework for ET practice, and the Developmental Model of LD that has evolved in application and explanation. Part 1 School Survey. This exploratory, cross-sectional study included a randomised sample of 277 participants in a private girl's school. A 7-10 minute screening was provided by five optometrists, with an expanded protocol including o-m function. Also assessed were academic standards of reading comprehension and spelling, reasoning, visual perception, phonological skills, auditory, visual and phonemic memory, and arm dominance. Results showed visual dysfunction and mixed eye dominance in approximately equal numbers. Of the 47% girls with visual dysfunction, not all had literacy problems; however, LD students had corresponding degrees of o-m dysfunction, memory deficit and mixed hand / arm dominance. Part 2 Intervention study. The Research Question for the Intervention Study was: Does the difference in learning standards depend on which eye is disadvantaged in the case of weak binocularity? This question was answered by determining the outcomes to literacy levels once normal binocular o-m function and stable eye dominance were established. Twenty-four students (6 to 18 years) had Behavioural Optometry assessment prior to commencing therapy and were found to have o-m dysfunction, undetected by previous standard optometry tests. Eye exercise results showed 62.5% of the group had changed from left to right eye dominance. The dominance criterion was set by this group, indicated by the right eye holding fixation through full range of fusional reserves (binocular overlap), together with superior eye-tracking speed >20% by the right, compared to the left, eye. Associated significant gains in literacy and phonemic memory were also achieved by the newly established 'right-eyed' group. In spite of undergoing identical treatment, the 'left-eyed' group retained limited foveal binocularity, and made less progress in literacy outcomes. Part 3 Two current Case Studies. Present ET practice benefited from insights gained from the 36% 'unsuccessful' participants of the previous study. Better therapy outcomes are achieved from an integrative motor-sensory approach, supported by Podiatry and Cranial Osteopathy. This detailed study involved two junior school boys who exemplified a common pattern of physical anomalies. For example, RW (8-year old male) had 'minimal brain damage' and LD that co-occur with unstable feet and o-m control, postural muscle imbalance, poor balance, motor co-ordination and dyspraxia. After 18, two-hour therapy sessions over nine months, he is now reading well, his motor co-ordination, eye tracking and writing are within the ‘low normal range’, and he is interacting competently with his peers. Learning difficulties can be conceptualised as a profile of immaturities. The results of this three part study have shown that once the 'hidden' handicap of right eye suppression is overcome with balanced binocular fields of vision, learning difficulties arc ameliorated. This is affirmed by the positive gains achieved by these students, not only in literacy skills but also 'outgrowing' immaturity in motor-sensory-perceptual development.
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Xie, Jeanne Yan. "The effect of development on spatial pattern separation in the hippocampus as quantified by the Homer1a immediate-early gene." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience, c2013, 2013. http://hdl.handle.net/10133/3414.
Full textAbstract:
This study sought to determine whether the DG, CA3, and CA1 regions contain
uniformly excitable populations and test the hypothesis that rapid addition of new, more
excitable, granule cells in prepubescence results in a low activation probability (P1) in the
DG. The immediate-early gene Homer1a was used as a neural activity marker to quantify
activation in juvenile (P28) and adult (~5 mo) rats during track running. The main finding
was that P1 in juveniles was substantially lower not only the DG, but also CA3 and CA1.
The P1 for a DG granule cell was close to 0 in juveniles, versus 0.58 in adults. The low P1
in juveniles indicates that sparse, but non-overlapping, subpopulations participate in
encoding events. Since sparse, orthogonal coding enhances a network’s ability to
decorrelate input patterns (Marr, 1971; McNaughton & Morris, 1987), the findings
suggest that juveniles likely possess greatly enhanced pattern separation ability.ix, 51 leaves : ill. ; 29 cm
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Gulbrandsen-MacDonald, Tine L., and University of Lethbridge Faculty of Arts and Science. "The role of the hippocampus and post-learning hippocampal activity in long-term consolidation of context memory." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience, c2011, 2011. http://hdl.handle.net/10133/2635.
Full textAbstract:
Sutherland, Sparks and Lehmann (2010) proposed a new theory of memory consolidation, termed Distributed Reinstatement Theory (DRT), where the hippocampus (HPC) is needed for initial encoding but some types of memories are established in non-HPC systems through post-learning HPC activity. An evaluation of the current methodology of temporary inactivation was conducted experimentally. By permanently implanting two bilateral guide cannulae in the HPC and infusing ropivacaine cellular activity could be reduced by 97%. Rats were trained in a context-fear paradigm. Six learning episodes distributed across three days made the memory resistant to HPC inactivation while three episodes did not. Blocking post-learning HPC activity following three of six training sessions failed to reduce the rat’s memory of the fearful context. These results fail to support DRT and indicate that one or more memory systems outside the HPC can acquire context memory without HPC post-event activity.x, 85 leaves : ill. ; 29 cm
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Knowles, Kristen. "Evolutionary and cognitive approaches to voice perception in humans : acoustic properties, personality and aesthetics." Thesis, University of Stirling, 2014. http://hdl.handle.net/1893/21784.
Full textAbstract:
Voices are used as a vehicle for language, and variation in the acoustic properties of voices also contains information about the speaker. Listeners use measurable qualities, such as pitch and formant traits, as cues to a speaker’s physical stature and attractiveness. Emotional states and personality characteristics are also judged from vocal stimuli. The research contained in this thesis examines vocal masculinity, aesthetics and personality, with an emphasis on the perception of prosocial traits including trustworthiness and cooperativeness. I will also explore themes which are more cognitive in nature, testing aspects of vocal stimuli which may affect trait attribution, memory and the ascription of identity. Chapters 2 and 3 explore systematic differences across vocal utterances, both in types of utterance using different classes of stimuli and across the time course of perception of the auditory signal. These chapters examine variation in acoustic measurements in addition to variation in listener attributions of commonly-judged speaker traits. The most important result from this work was that evaluations of attractiveness made using spontaneous speech correlated with those made using scripted speech recordings, but did not correlate with those made of the same persons using vowel stimuli. This calls into question the use of sustained vowel sounds for the attainment of ratings of subjective characteristics. Vowel and single-word stimuli are also quite short – while I found that attributions of masculinity were reliable at very short exposure times, more subjective traits like attractiveness and trustworthiness require a longer exposure time to elicit reliable attributions. I conclude with recommending an exposure time of at least 5 seconds in duration for such traits to be reliably assessed. Chapter 4 examines what vocal traits affect perceptions of pro-social qualities using both natural and manipulated variation in voices. While feminine pitch traits (F0 and F0-SD) were linked to cooperativeness ratings, masculine formant traits (Df and Pf) were also associated with cooperativeness. The relative importance of these traits as social signals is discussed. Chapter 5 questions what makes a voice memorable, and helps to differentiate between memory for individual voice identities and for the content which was spoken by administering recognition tests both within and across sensory modalities. While the data suggest that experimental manipulation of voice pitch did not influence memory for vocalised stimuli, attractive male voices were better remembered than unattractive voices, independent of pitch manipulation. Memory for cross-modal (textual) content was enhanced by raising the voice pitch of both male and female speakers. I link this pattern of results to the perceived dominance of voices which have been raised and lowered in pitch, and how this might impact how memories are formed and retained. Chapter 6 examines masculinity across visual and auditory sensory modalities using a cross-modal matching task. While participants were able to match voices to muted videos of both male and female speakers at rates above chance, and to static face images of men (but not women), differences in masculinity did not influence observers in their judgements, and voice and face masculinity were not correlated. These results are discussed in terms of the generally-accepted theory that masculinity and femininity in faces and voices communicate the same underlying genetic quality. The biological mechanisms by which vocal and facial masculinity could develop independently are speculated.
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Tichiwanhuyi, Tendayi Stephen. "The acute impact of extended aerobic exercise on cognitive performance." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1018182.
Full textAbstract:
Previous research has established a relationship between exercise and cognition, with more emphasis on this ascertained link, being made on the effects of long term and endurance exercise on cognition. However, enhanced worker effectiveness relies on a strong acute collaboration of physical and cognitive performance during task execution. As a result, the purpose of this study was to examine the acute effects of extended aerobic exercise on visual perception, working memory and motor responses, and to achieve this 24 participants (12 males and 12 females) aged between 18 and 24 participated in a 2 bout cycling exercise. The experimental condition had cycling resistance set at 60 percent of each individual’s maximum aerobic output and the control condition had zero cycling resistance, where three cognitive tasks were performed at 10 minute intervals during the cycling exercise. The results showed that exercise did not affect any significant changes on the cognitive performance measures over the entire cycling duration, as well as during the exercise phase (cycling with resistance). However, visual perception improved significantly (p<0.05) immediately after exercise. This led to the conclusion that moderate to high intensity exercise when performed for an extended duration, has selective effects on certain cognitive performance measures, with the time at which the performance is measured during the exercise being a relevant factor to be considered for maximum activation effects of the exercise.
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Sousa, Grazielle Aurelina Fraga de. "Desempenho de estudantes universitários em testes matutinos e vespertinos para avaliação da memória episódica e operacional." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314129.
Full textAbstract:
Orientador: Elenice Aparecida de Moraes FerrariDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-17T13:20:19Z (GMT). No. of bitstreams: 1 Sousa_GrazielleAurelinaFragade_M.pdf: 2482319 bytes, checksum: 98003776bf4be1025c31d965be705e09 (MD5) Previous issue date: 2010
Resumo: Este estudo investigou se o desempenho de estudantes universitários, em testes de memória episódica e operacional, varia em função do horário e do intervalo de tempo em que são realizados os testes de evocação. Na Fase 1, o Questionário Cronotipo foi utilizado para classificar o tipo cronobiológico. Dos 396 alunos avaliados, 59% foram classificados como intermediários, 35% como vespertinos e 6% como matutinos. Na Fase 2, foi avaliada uma amostra de 43 alunos, de ambos os sexos, classificados como intermediários, com 20,12 ± 2,18 anos de idade, falantes nativos de Português, sem histórico de distúrbios do sono ou uso de drogas psicoativas. Foram constituídos quatro grupos de acordo com os horários das sessões de treino/teste imediato e teste tardio: GMN - treino pela manhã e teste à noite, após 12horas; GMM - treino pela manhã e teste pela manhã, após 24 horas; GNM - treino à noite e teste pela manhã, após 12 horas; GNN - treino à noite e teste à noite, após 24 horas. Para avaliação da memória episódica e operacional foram utilizados: Teste de Aprendizagem Auditivo Verbal de Rey (TAAVR), Teste de Memória Lógica (TML), Teste de Extensão de Dígitos e Teste dos Blocos de Corsi. O Diário de Sono foi usado para avaliar o ciclo vigília-sono e o uso de termistor e de actímetro permitiu avaliar os ritmos de temperatura de punho e atividade motora. Questionários específicos foram utilizados para avaliação da percepção de estresse, ansiedade e estado de humor. Os dados do TAAVR e TML em três diferentes momentos de avaliação (imediato, após 30 minutos e tardio - após 12 ou 24horas) não indicaram efeito do horário ou do intervalo entre os testes de evocação (ANOVA; p > 0,05); no entanto, foi observada uma redução significativa dos escores ao longo dos momentos de avaliação (ANOVA; p < 0,05). Os escores médios obtidos no teste 30 minutos e no teste tardio do TAAVR correlacionaram-se positivamente com a média de duração do sono global (Teste de Spearman, p < 0,05). A média de duração do sono anterior à sessão de teste imediato apresentou correlação positiva com o escore médio do teste tardio do TML (Teste de Spearman, p < 0,05). Não houve efeito de horário ou de sessão sobre os índices do Teste de Extensão de Dígitos, Teste dos Blocos de Corsi e fatores de avaliação do humor (ANOVA; p > 0,05). Os grupos não diferiram quanto ao índice de estresse percebido e características de traço e estado de ansiedade (ANOVA, p > 0,05). O ritmo da temperatura de punho e o ritmo da atividade motora apresentaram relações de fase adequadas para a maioria dos sujeitos avaliados. A distribuição dos cronotipos na população avaliada concorda com os dados descritos para a população brasileira. Os dados indicaram a ausência de efeito do horário sobre o desempenho de indivíduos com cronotipo intermediário e sugerem uma relação entre a duração do sono e a memória episódica verbal. Estas evidências contribuem para o conhecimento sobre a variação do desempenho cognitivo durante a fase de vigília
Abstract: The aim of this study was to investigate if the performance of undergraduate students in episodic and working memory tests is influenced by the time-of-day and the interval between the retrieval tests. In Phase 1, the Morningness-Eveningness Questionnaire was used for assessment of the chonotype in a sample of students. Of 396 students assessed, 59% were classified as intermediate-type, 35% evening-type and 6% morning-type. The Phase 2 was conducted with 43 students classified as intermediatetype, both genders, with 20.12 ± 2.18 years old, native Portuguese speakers, without history of sleep disorders or use of drugs known to influence sleep and memory. These students were allocated in four groups according to the time-of-day of the training and the tests: GMN - trained in the morning (7:30 a.m.) and tested at same day, at night (6:30 p.m.); GMM - trained in the morning (7:30 a.m.) and tested after 24 hours (7:30 a.m.); GNM - trained at night (6:30 p.m.) and tested in the morning of the next day (7:30 a.m.); and the GNN - trained at night (6:30 p.m.) and tested after 24 hours (6:30 p.m.). The Rey Auditory Learning Test (RAVLT), Logical Memory Test (LMT), Corsi Block- Tapping Test and Digit Span Test were used to assess episodic and working memories. The sleep-wake cycle was assessed by sleep-logs and the wrist temperature and motor activity rhythmics was evaluated by thermistor and actigraphy. The levels of perceived stress, state of anxiety and mood were also evaluated. There was no time-of-day effect or interval effect on the retrieval of the RAVLT and LMT in the immediate test, 30 minutes test and delayed test - after 12 or 24 hours (ANOVA, p > 0.05). However, the scores showed a significant decrease across these three assessments (ANOVA p < 0.05). Positive correlation was observed between the mean sleep duration and the mean scores of the RAVLT after 30 minutes and in the delayed test (Spearman Test, p < 0.05). The mean of sleep duration before the immediate test was positively correlated with the LMT score during the delayed test (Spearman Test, p < 0.05). There was no effect of the time-of-day on Digit Span Test, Corsi Block-Tapping Test and mood assessment (ANOVA, p > 0.05). No between-group differences occurred in the level of perceived stress and trait-state anxiety (p > 0.05). The rhythm of wrist temperature and the rhythm of motor activity showed appropriate phase relations for the most part of evaluated subjects. The data indicate absence of time-of-day effect on the performance of intermediate-type individuals and suggest a relationship between memory and the sleep duration. Such evidence contributes to our understanding of the variation in cognitive performance during the wake period
Mestrado
Fisiologia
Mestre em Biologia Funcional e Molecular
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Carbajal, Ivan. "An Investlarks and Hearts: Circadian Mismatch and Effort Intensity." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157572/.
Full textAbstract:
My experiment concerned the influence of chronobiological (circadian) rhythm on fatigue, effort, and cardiovascular (CV) response. It evaluated responses of morning people (Larks) presented an easy or difficult recognition memory task at a time congruent or incongruent with their rhythm. Based on an extension of a conceptual analysis of fatigue influence, my central prediction was that circadian rhythm would combine interactionally with task difficulty to determine effort and associated CV responses. Specifically, effort and associated CV responses were expected to be (1) positively correspondent to task difficulty in the morning (stronger where difficulty is high), but (2) negatively correspondent to difficulty in the evening (stronger where difficulty is low). Preliminary results showed concerning gender effects on difficulty appraisal of the task, thus we examined women and men's data separately. CV findings for women were broadly, but not completely, consistent with predictions. Analyses revealed no group differences in CV response for Lark men.
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Fassbender, Eric. "VirSchool the effect of music on memory for facts learned in a virtual environment /." Phd thesis, Australia : Macquarie University, 2009. http://hdl.handle.net/1959.14/76852.
Full textAbstract:
Thesis (PhD)--Macquarie University, Faculty of Science, Dept. of Computing, 2009.Bibliography: p. [265]-280.
Introduction -- Literature review -- Method -- Experiments -- Conclusion.
Video games are becoming increasingly popular and their level of sophistication comes close to that of professional movie productions. Educational institutions and corporations are beginning to use video games for teaching purposes, however, not much is known about the use and effectiveness of video games for such purposes. One even less explored factor in video games is the music that is played throughout the course of the games. Little is known about the role that this music plays in cognitive processes and what effect background music has on players' memory. It is this question that the present thesis explores by asking which effect background music has on participants' memory for facts that are learned from a virtual environment. -- To answer the research question, a computer-animated history lesson, called VirSchool, was created which used the history of the Macquarie Lighthouse in Sydney as a basis for two experiments. Different musical stimuli accompanied the audio-visual presentation of the history topic. These stimuli were tested for their effectiveness to support participants' memory. The VirSchool history lesson was first presented in a Reality Center (a highly immersive, semi-cylindrical 3 projector display system) and one soundtrack was identified which showed a statistically significant improvement in the number of facts that participants remembered correctly from the VirSchool history lesson. Furthermore, Experiment 1 investigated how variations of tempo and pitch of the musical stimuli affected memory performance. It was found that slow tempo and low pitch were beneficial for remembrance of facts from the VirSchool history lesson. -- The beneficial soundtrack that was identified in Experiment 1 was reduced in tempo and lowered in pitch and was subsequently used as the sole musical stimulus in Experiment 2. Furthermore, because of equipment failure, Experiment 2 offered the opportunity to compare memory performance of participants in the Reality Center and a 3-monitor display system, which was used as a replacement for the defect Reality Center. Results showed that, against expectation, the memory for facts from the VirSchool history lesson was significantly better in the less immersive 3-monitor display system. Moreover, manipulated background music played in the second five and a half minutes of the VirSchool history lesson in the Reality Center resulted in a statistically significant improvement of participants' remembrance of facts from the second five and a half minutes of the VirSchool history lesson. The opposite effect was observed in the 3-monitor display system where participants remembered less information from the second five and a half minutes of the VirSchool history lesson if music was played in the second five and a half minutes of the VirSchool history lesson. -- The results from the present study reveal that in some circumstances music has a significant influence on memory in a virtual environment and in others it does not. These findings contribute towards and encourage further investigation of our understanding of the role that music plays in virtual learning environments so that they may be utilised to advance learning of future generations of students.
Mode of access: World Wide Web.
280 p. ill. (some col.)
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Vandenberghe, Muriel. "Les processus d'apprentissage préservés dans l'amnésie: étude neuropsychologique et cognitive." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210585.
Full text
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Oestreich, Jörg. "From neural mechanisms to ecology: a neuroethological approach to a novel form of memory." Thesis, 2004. http://hdl.handle.net/2152/1377.
Full text
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Mumby, David Gerald. "The development of a rat model of brain-damage-produced amnesia." Thesis, 1992. http://hdl.handle.net/2429/3293.
Full textAbstract:
The nonrecurring-items delayed nonmatching-to-sample (DNMS) task is an integral part of
contemporary monkey models of brain-damage-produced amnesia. This thesis began the development
of a comparable rat model of brain-damage-produced amnesia. First, a DNMS task for rats was
designed by adapting key features of the monkey task. Then, the rat DNMS task was studied in three
experiments; each assessed the comparability of the rat DNMS task to the monkey DNMS task.
Experiment 1 determined the rate at which the rat DNMS task is learned and the asymptotic level at
which it is performed, Experiment 2 assessed the memory abilities that it taps, and Experiment 3
investigated the brain structures that are involved i n its performance.
In Experiment 1, rats were trained on the DNMS task and their performance was assessed at
retention delays of 4, 15, 60, 120, and 600 s. All of the rats learned the DNMS task, and their
performance was comparable to that commonly reported for monkeys in terms of both the rate at
which they acquired the nonmatching rule at a brief retention delay and their asymptotic accuracy at
delays of up to 120 s. These results establish that rats can perform a DNMS task that closely resembles
the monkey DNMS task and that they can approximate the level of performance that is achieved by
monkeys.
Experiment 2 examined the effects of distraction during the retention delay on the DNMS performance of rats. Rats were tested at retention delays of 60 s. On half of the trials, the rats
performed a distraction task during the retention delay; on the other half, they did not. Consistent with
findings from monkeys and humans, distraction during the retention delay disrupted the DNMS
performance of rats. This suggests that similar memory abilities are involved in the DNMS
performance of rats, monkeys, and humans. Experiment 3 investigated the effects of separate and combined bilateral lesions of the
hippocampus and the amygdala on DNMS performance in pretrained rats. Rats were tested both
before and after surgery at retention delays of 4, 15, 60, 120, and 600 s. Each experimental rat received
bilateral lesions of the hippocampus, amygdala, or both. There were no significant differences among
the three experimental groups, and the rats in each of the three experimental groups were significantly
impaired, in comparison to no-surgery control rats, only at the 600-s delay. In contrast, rats that had
sustained inadvertent entorhinal and perirhinal cortex damage during surgery displayed profound
D N M S deficits. These results parallel the results of recent studies of the neural basis of DNMS in
monkeys. They suggest that, in contrast to one previously popular view, neither the hippocampus nor
the amygdala play a critical role in the DNMS of pretrained animals and that the entorhinal and
perirhinal cortex are critically involved.
On the basis of these findings, it appears that the rat DNMS task may prove to be a useful
component of rat models of brain-damage-produced amnesia. This conclusion is supported by the
preliminary results of several experiments that are currently employing the task.
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"Prefrontal involvement in memory encoding and retrieval: an fMRI study." 2002. http://library.cuhk.edu.hk/record=b5891182.
Full textAbstract:
He Wu-jing.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.
Includes bibliographical references (leaves 48-57).
Abstracts in English and Chinese.
Abstract --- p.ii
Chinese Abstract (論文摘要) --- p.iv
Acknowledgements --- p.vi
Table of Contents --- p.vii
List of Tables --- p.viii
List of Figures --- p.ix
Chapter Chapter 1 - --- fMRI as a Neuroimaging Method --- p.1
Chapter Chapter 2 - --- An Review of the Relationship Between Prefrontal Lobes and Memory --- p.6
Chapter Chapter 3 - --- The Present Study --- p.12
Chapter Chapter 4 - --- Method --- p.17
Chapter Chapter 5 - --- Results --- p.25
Chapter Chapter 6 - --- Discussion --- p.41
References --- p.48
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Brim, Brenna L. "The effects of enhanced expression of the GluN2B (NR2B) subunit of the N-methyl-D-aspartate (NMDA) receptor on memory in aged animals." Thesis, 2012. http://hdl.handle.net/1957/33934.
Full textAbstract:
As the aging population continues to grow worldwide, age-related complications are becoming more apparent within the aging population. One of the first age-related complications to become apparent is age-associated memory impairment and it can make the elderly more dependent on caregivers early on. The N-methyl-D-aspartate (NMDA) receptor is important to learning and memory and appears to be especially vulnerable to the process of aging. The density of NMDA receptors declines with age more than any other ionotropic glutamate receptor. Both the density of NMDA receptors and the mRNA and protein expression of its subunits decline with age. In particular, the GluN2B subunit of the NMDA receptor shows the greatest age-related declines in expression across multiple brain regions, including the frontal lobe (including the prefrontal and frontal cortices), caudate nucleus and hippocampus. These declines are strongly correlated to age-related declines in spatial memory. Specifically, age-related decreases in the protein expression of the GluN2B subunit within crude synaptosomes of the frontal cortex of C57BL/6 mice show a relationship to the declines in performance in a long-term spatial memory task across age groups. However, within the population of aged mice, there was a subpopulation of aged mice in which higher expression of the GluN2B subunit within the synaptic membrane of the hippocampus was associated with poorer performance in the same task. Moreover, transgenic mice designed to express higher
levels of the GluN2B subunit from birth also possess superior memory, including spatial memory, across adulthood to middle-age. Taken together, these data led to the hypothesis that increasing the expression of the GluN2B subunit within the aged brain could potentially alleviate age-related declines in memory. However, increasing its expression regionally was first examined since higher expression of the GluN2B subunit within the hippocampus has been associated with poorer memory in aged animals.
Since age-related decreases in the protein expression of the GluN2B subunit within the frontal cortex show a relationship to impaired memory function, the first study was designed to determine if increasing GluN2B subunit expression in the frontal lobe would improve memory in aged mice. Mice received bilateral injections of either an adenoviral vector, containing cDNA specific for the GluN2B subunit and enhanced Green Fluorescent Protein (eGFP) (GluN2B vector); an adenoviral vector containing only the cDNA for eGFP (control vector); or vehicle into their frontal lobe. Spatial memory, cognitive flexibility and associative memory were assessed using the Morris water maze. Aged mice, with increased GluN2B subunit expression in the frontal lobe, exhibited improved long-term spatial memory, comparable to young mice, in the second day of training. Moreover, a higher concentration of the specific GluN2B antagonist, Ro 25-6981, was required to impair long-term spatial memory in aged mice with enhanced GluN2B subunit expression, as compared to aged controls. The requirement for greater antagonism in aged mice to block memory performance suggests that the number of GluN2B-containing receptors in their frontal lobe was enhanced and contributed to the improved memory. This study provides suggestive evidence that therapies that enhance GluN2B subunit expression within the aged brain could have the potential to ameliorate age-related memory loss.
Since higher expression of the GluN2B subunit within the hippocampus of aged mice is associated with poorer memory, the second study was designed to determine if increasing GluN2B subunit expression in the hippocampus would improve or further impair memory in aged mice. This would help to determine if a therapy aimed at enhancing the GluN2B subunit expression or function of GluN2B-containing receptors throughout the aged brain could help ameliorate age-associated memory loss. Mice were injected bilaterally with either the GluN2B vector, a control vector or vehicle into the hippocampus. Spatial memory, cognitive flexibility and associative memory were assessed using the Morris water maze. Aged mice, with increased GluN2B subunit expression in the hippocampus, exhibited improved long-term spatial memory, comparable to young mice, early in training. However, there was a trend for impaired memory later in the long-term spatial memory trials. Still, these data suggest that enhancing GluN2B subunit expression in the aged hippocampus could be more beneficial to memory than harmful. In addition, the results of this study suggest that enhancing GluN2B subunit expression in different brain regions may improve memory at different phases of learning. Therefore, therapies that enhance GluN2B subunit expression throughout the aged brain could help ameliorate age-related memory loss. The first two studies demonstrated that enhancing the expression of the GluN2B subunit within either the frontal lobe or hippocampus of the aged brain has the potential to reduce age-related memory declines. However, the increase was not global nor specific to the synapse. Therefore, a third study was developed with the intent of garnering a more global increase in GluN2B subunit expression that was localized to the synapse. Cyclin dependent kinase 5 (Cdk5) enhances endocytosis of the GluN2B subunit-containing NMDA receptors from the synapse. Previous research has shown that inhibiting Cdk5 increases the number of GluN2B subunits at the synapse and within the whole cell and improves memory in young mice. This
study was designed to determine if using antisense phosphorodiamidate morpholino oligomers (Morpholinos) to decrease the expression of Cdk5 protein within the brain would improve memory in aged mice. Morpholinos were conjugated to a cell penetrating peptide, which enhances cellular uptake, and delivered bilaterally to the lateral ventricles of both young and aged mice via acute stereotaxic injection. Treatments consisted of equivalent volumes and concentrations of either vehicle, control Morpholino or a Morpholino targeting the mRNA of Cdk5 (Cdk5 Morpholino). Memory was evaluated in the Morris water maze and using a novel object recognition task. Aged mice treated with the Cdk5 Morpholino exhibited improved early acquisition and spatial bias in the long-term spatial memory trials, as well as improved performance overall, compared to control Morpholino-treated aged animals. However, aged mice treated with the Cdk5 Morpholino performed similarly to vehicle-treated aged animals. The presence of the peptide-conjugated Morpholinos within the brain may have worsened performance in the Morris water maze task since control Morpholino-treated animals performed significantly worse than vehicle-treated animals. In concurrence, there was significantly greater gliosis in peptide-conjugated Morpholino-treated animals over vehicle-treated brains, suggesting it was neurotoxic. In contrast, young mice treated with the Cdk5 Morpholino showed impaired early acquisition and spatial bias but a trend for improved later learning in the long-term spatial memory task compared to control Morpholino-treated animals. Treatment with the Cdk5 Morpholino had no significant effect on cognitive flexibility, associative memory or novel object recognition for young or aged animals. Immunohistochemistry revealed increased GluN2B subunit expression within cells with characteristics of neurons and astroglia in regions of the frontal lobe, caudate nucleus and hippocampus of aged mice who received the Cdk5 Morpholino compared to control treatments. However, the increased GluN2B subunit expression appeared to be greater within
the hippocampus. These results suggest that inhibiting the translation of Cdk5 using Morpholinos increased GluN2B subunit expression in both young and aged mice and may have contributed to the improved long-term spatial memory observed in aged mice, despite the Morpholino being administered at a presumably toxic concentration. An additional group of mice was used to determine a non-neurotoxic dosage of the peptide conjugated Morpholino. However, future studies are needed to determine the efficacy of the Cdk5 Morpholino at this dosage.
Taken together, the studies presented here suggest that increasing expression of the GluN2B subunit within the aged brain does improve age-associated memory declines. In addition, cell penetrating peptide- conjugated Morpholinos show promise as tools for genetic manipulation within the brain and Cdk5 could prove to be a novel target for enhancing GluN2B subunit expression within the aged brain. Though future studies are needed, the studies presented here do suggest that therapies that enhance GluN2B subunit expression within the aged brain have the potential to help ameliorate memory loss. However, since enhanced GluN2B subunit expression itself can increase the potential for excitotoxicity, an optimal dose of such a therapeutic would need to be determined.Graduation date: 2013
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Kaifosh, Patrick William John. "The neural circuit basis of learning." Thesis, 2016. https://doi.org/10.7916/D8416WXR.
Full textAbstract:
The astounding capacity for learning ranks among the nervous system’s most impressive features. This thesis comprises studies employing varied approaches to improve understanding, at the level of neural circuits, of the brain’s capacity for learning.
The first part of the thesis contains investigations of hippocampal circuitry – both theoretical work and experimental work in the mouse Mus musculus – as a model system for declarative memory. To begin, Chapter 2 presents a theory of hippocampal memory storage and retrieval that reflects nonlinear dendritic processing within hippocampal pyramidal neurons. As a prelude to the experimental work that comprises the remainder of this part, Chapter 3 describes an open source software platform that we have developed for analysis of data acquired with in vivo Ca2+ imaging, the main experimental technique used throughout the remainder of this part of the thesis. As a first application of this technique, Chapter 4 characterizes the content of signaling at synapses between GABAergic neurons of the medial septum and interneurons in stratum oriens of hippocampal area CA1. Chapter 5 then combines these techniques with optogenetic, pharmacogenetic, and pharmacological manipulations to uncover inhibitory circuit mechanisms underlying fear learning.
The second part of this thesis focuses on the cerebellum-like electrosensory lobe in the weakly electric mormyrid fish Gnathonemus petersii, as a model system for non-declarative memory. In Chapter 6, we study how short-duration EOD motor commands are recoded into a complex temporal basis in the granule cell layer, which can be used to cancel Purkinje-like cell firing to the longer duration and temporally varying EOD-driven sensory responses. In Chapter 7, we consider not only the temporal aspects of the granule cell code, but also the encoding of body position provided from proprioceptive and efference copy sources. Together these studies clarify how the cerebellum-like circuitry of the electrosensory lobe combines information of different forms and then uses this combined information to predict the complex dependence of sensory responses on body position and timing relative to electric organ discharge.
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Hartzler, Bryan Joseph. "Blackouts the etiology of alcohol-induced amnestic episodes and their effect on alcohol-related beliefs /." Thesis, 2003. http://wwwlib.umi.com/cr/utexas/fullcit?p3116323.
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"The effects of music training on memory of children." 2001. http://library.cuhk.edu.hk/record=b5890695.
Full textAbstract:
Yim-chi Ho."Running head: Effects of music training on memory of children."
Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.
Includes bibliographical references (leaves 51-65).
Abstracts in English and Chinese.
ABSTRACT (English Version) --- p.ii
ABSTRACT (Chinese Version) --- p.iii
ACKNOWLEDGEMENTS --- p.iv
TABLE OF CONTENTS --- p.v
LIST OF TABLES --- p.vi
LIST OF FIGURES --- p.vii
Chapter CHAPTER I - --- INTRODUCTION --- p.1
Chapter CHAPTER II - --- METHOD --- p.13
Chapter CHAPTER III - --- RESULTS --- p.19
Chapter CHAPTER IV - --- DISCUSSION --- p.42
REFERENCES --- p.51
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Mays, Jaidan Leigh. "Effects of Edublox training versus Edublox training combined with cervical spinal manipulative therapy on visual memory." Thesis, 2014. http://hdl.handle.net/10210/9648.
Full textAbstract:
M.Tech. (Chiropractic)Brain hibernation or cerebral dysfunction theory is the diminishing of brain function due to poor blood flow as a result of compression of the vertebral, basilar, internal carotid and subclavian arteries (Buchanan, 2004). Compression is usually due to skeletal malalignment, ligamentous or muscular in origin and correction of this by cervical spine manipulation suggests that the above difficulties may be improved with manipulative and manual techniques (Buchanan, 2005). Thomas and Wood (1992), suggest that there is a correlation between upper cervical adjustments and improved mental function. This has been shown by Shambaugh, Pearlman and Hauck (1991), who showed that after an adjustment, there was an improved brain stem evoked response which indicated that neural messages were travelling through the brain stem quicker or with less delay. Terrett (1993), has proposed that cervical manipulative therapy results in augmented cerebral blood flow, which culminates in hibernating areas of the brain becoming functional again. The higher cognitive skills tend to be affected by the decrease in blood flow. Cognitive skills are vital to the process of learning, spelling and reading. Edublox is a company that has special training programmes to develop these skills to maximise a childs potential. The aim of this study is to determine the effects of cervical manipulations combined with Edublox training versus Edublox training alone on visual spatial memory. The focus of the study would be to determine whether chiropractic cervical manipulation has a significant effect on mental function and visual memory when combined with Edublox training. The study will include a total of 34 participants split into two groups, one receiving Edublox training and the other receiving Edublox training combined with cervical spine manipulations. Participants approximately between the ages of ten and thirteen years of age will be included in this study. The manipulation group will receive spinal manipulative therapy followed by both groups receiving the same Edublox training session to limit variation. The participants shall receive an intense program of Edublox training, every day for the duration of five days and the combined group will receive adjustment every other day. The research will be conducted at the premises of Confidence College. Subjective and objective measurements will be taken at the beginning and at the end of the five days. The subjective measurement will include an Observer Memory Questionnaire – Parent Form that will be completed by the parent of the child based on their view of their child’s memory. The objective measurement will include two sub-tests from the Visual Perceptual Skills Test 3, namely the visual memory (VM) and visual sequential memory (VSM) components.