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Journal articles on the topic 'Cortical functional specialization'
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Fiebelkorn, Ian C., and Sabine Kastner. "Functional Specialization in the Attention Network." Annual Review of Psychology 71, no. 1 (January 4, 2020): 221–49. http://dx.doi.org/10.1146/annurev-psych-010418-103429.
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Spatial attention is comprised of neural mechanisms that boost sensory processing at a behaviorally relevant location while filtering out competing information. The present review examines functional specialization in the network of brain regions that directs such preferential processing. This attention network includes both cortical (e.g., frontal and parietal cortices) and subcortical (e.g., the superior colliculus and the pulvinar nucleus of the thalamus) structures. Here, we piece together existing evidence that these various nodes of the attention network have dissociable functional roles by synthesizing results from electrophysiology and neuroimaging studies. We describe functional specialization across several dimensions (e.g., at different processing stages and within different behavioral contexts), while focusing on spatial attention as a dynamic process that unfolds over time. Functional contributions from each node of the attention network can change on a moment-to-moment timescale, providing the necessary cognitive flexibility for sampling from highly dynamic environments.
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Pauli, Wolfgang M., Randall C. O’Reilly, Tal Yarkoni, and Tor D. Wager. "Regional specialization within the human striatum for diverse psychological functions." Proceedings of the National Academy of Sciences 113, no. 7 (February 1, 2016): 1907–12. http://dx.doi.org/10.1073/pnas.1507610113.
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Decades of animal and human neuroimaging research have identified distinct, but overlapping, striatal zones, which are interconnected with separable corticostriatal circuits, and are crucial for the organization of functional systems. Despite continuous efforts to subdivide the human striatum based on anatomical and resting-state functional connectivity, characterizing the different psychological processes related to each zone remains a work in progress. Using an unbiased, data-driven approach, we analyzed large-scale coactivation data from 5,809 human imaging studies. We (i) identified five distinct striatal zones that exhibited discrete patterns of coactivation with cortical brain regions across distinct psychological processes and (ii) identified the different psychological processes associated with each zone. We found that the reported pattern of cortical activation reliably predicted which striatal zone was most strongly activated. Critically, activation in each functional zone could be associated with distinct psychological processes directly, rather than inferred indirectly from psychological functions attributed to associated cortices. Consistent with well-established findings, we found an association of the ventral striatum (VS) with reward processing. Confirming less well-established findings, the VS and adjacent anterior caudate were associated with evaluating the value of rewards and actions, respectively. Furthermore, our results confirmed a sometimes overlooked specialization of the posterior caudate nucleus for executive functions, often considered the exclusive domain of frontoparietal cortical circuits. Our findings provide a precise functional map of regional specialization within the human striatum, both in terms of the differential cortical regions and psychological functions associated with each striatal zone.
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Goldman-Rakic, Patricia S. "Structural and Functional Specialization of Cortical Pyramidal Cells." Developmental Neuropsychology 16, no. 3 (December 1, 1999): 317–20. http://dx.doi.org/10.1207/s15326942dn1603_4.
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Andermann, Mark L., Aaron M. Kerlin, Demetris K. Roumis, Lindsey L. Glickfeld, and R. Clay Reid. "Functional Specialization of Mouse Higher Visual Cortical Areas." Neuron 72, no. 6 (December 2011): 1025–39. http://dx.doi.org/10.1016/j.neuron.2011.11.013.
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Marshel, James H., Marina E. Garrett, Ian Nauhaus, and Edward M. Callaway. "Functional Specialization of Seven Mouse Visual Cortical Areas." Neuron 72, no. 6 (December 2011): 1040–54. http://dx.doi.org/10.1016/j.neuron.2011.12.004.
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Kühnis, Jürg, Stefan Elmer, and Lutz Jäncke. "Auditory Evoked Responses in Musicians during Passive Vowel Listening Are Modulated by Functional Connectivity between Bilateral Auditory-related Brain Regions." Journal of Cognitive Neuroscience 26, no. 12 (December 2014): 2750–61. http://dx.doi.org/10.1162/jocn_a_00674.
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Currently, there is striking evidence showing that professional musical training can substantially alter the response properties of auditory-related cortical fields. Such plastic changes have previously been shown not only to abet the processing of musical sounds, but likewise spectral and temporal aspects of speech. Therefore, here we used the EEG technique and measured a sample of musicians and nonmusicians while the participants were passively exposed to artificial vowels in the context of an oddball paradigm. Thereby, we evaluated whether increased intracerebral functional connectivity between bilateral auditory-related brain regions may promote sensory specialization in musicians, as reflected by altered cortical N1 and P2 responses. This assumption builds on the reasoning that sensory specialization is dependent, at least in part, on the amount of synchronization between the two auditory-related cortices. Results clearly revealed that auditory-evoked N1 responses were shaped by musical expertise. In addition, in line with our reasoning musicians showed an overall increased intracerebral functional connectivity (as indexed by lagged phase synchronization) in theta, alpha, and beta bands. Finally, within-group correlative analyses indicated a relationship between intracerebral beta band connectivity and cortical N1 responses, however only within the musicians' group. Taken together, we provide first electrophysiological evidence for a relationship between musical expertise, auditory-evoked brain responses, and intracerebral functional connectivity among auditory-related brain regions.
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Saleh, Mai. "Intellectual Style Inventory (ISI): Learning Style Assessment after Cortical Functional Specialization." British Journal of Education, Society & Behavioural Science 4, no. 7 (January 10, 2014): 987–1005. http://dx.doi.org/10.9734/bjesbs/2014/8751.
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St-Onge, Marie-Pierre, Melissa Sy, Steven B. Heymsfield, and Joy Hirsch. "Human Cortical Specialization for Food: a Functional Magnetic Resonance Imaging Investigation." Journal of Nutrition 135, no. 5 (May 1, 2005): 1014–18. http://dx.doi.org/10.1093/jn/135.5.1014.
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Toulmin, Hilary, Christian F. Beckmann, Jonathan O'Muircheartaigh, Gareth Ball, Pumza Nongena, Antonios Makropoulos, Ashraf Ederies, et al. "Specialization and integration of functional thalamocortical connectivity in the human infant." Proceedings of the National Academy of Sciences 112, no. 20 (May 4, 2015): 6485–90. http://dx.doi.org/10.1073/pnas.1422638112.
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Connections between the thalamus and cortex develop rapidly before birth, and aberrant cerebral maturation during this period may underlie a number of neurodevelopmental disorders. To define functional thalamocortical connectivity at the normal time of birth, we used functional MRI (fMRI) to measure blood oxygen level-dependent (BOLD) signals in 66 infants, 47 of whom were at high risk of neurocognitive impairment because of birth before 33 wk of gestation and 19 of whom were term infants. We segmented the thalamus based on correlation with functionally defined cortical components using independent component analysis (ICA) and seed-based correlations. After parcellating the cortex using ICA and segmenting the thalamus based on dominant connections with cortical parcellations, we observed a near-facsimile of the adult functional parcellation. Additional analysis revealed that BOLD signal in heteromodal association cortex typically had more widespread and overlapping thalamic representations than primary sensory cortex. Notably, more extreme prematurity was associated with increased functional connectivity between thalamus and lateral primary sensory cortex but reduced connectivity between thalamus and cortex in the prefrontal, insular and anterior cingulate regions. This work suggests that, in early infancy, functional integration through thalamocortical connections depends on significant functional overlap in the topographic organization of the thalamus and that the experience of premature extrauterine life modulates network development, altering the maturation of networks thought to support salience, executive, integrative, and cognitive functions.
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Linden, David E. J., Nikolaas N. Oosterhof, Christoph Klein, and Paul E. Downing. "Mapping brain activation and information during category-specific visual working memory." Journal of Neurophysiology 107, no. 2 (January 15, 2012): 628–39. http://dx.doi.org/10.1152/jn.00105.2011.
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How is working memory for different visual categories supported in the brain? Do the same principles of cortical specialization that govern the initial processing and encoding of visual stimuli also apply to their short-term maintenance? We investigated these questions with a delayed discrimination paradigm for faces, bodies, flowers, and scenes and applied both univariate and multivariate analyses to functional magnetic resonance imaging (fMRI) data. Activity during encoding followed the well-known specialization in posterior areas. During the delay interval, activity shifted to frontal and parietal regions but was not specialized for category. Conversely, activity in visual areas returned to baseline during that interval but showed some evidence of category specialization on multivariate pattern analysis (MVPA). We conclude that principles of cortical activation differ between encoding and maintenance of visual material. Whereas perceptual processes rely on specialized regions in occipitotemporal cortex, maintenance involves the activation of a frontoparietal network that seems to require little specialization at the category level. We also confirm previous findings that MVPA can extract information from fMRI signals in the absence of suprathreshold activation and that such signals from visual areas can reflect the material stored in memory.
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Vermaercke, Ben, Florian J. Gerich, Ellen Ytebrouck, Lutgarde Arckens, Hans P. Op de Beeck, and Gert Van den Bergh. "Functional specialization in rat occipital and temporal visual cortex." Journal of Neurophysiology 112, no. 8 (October 15, 2014): 1963–83. http://dx.doi.org/10.1152/jn.00737.2013.
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Recent studies have revealed a surprising degree of functional specialization in rodent visual cortex. Anatomically, suggestions have been made about the existence of hierarchical pathways with similarities to the ventral and dorsal pathways in primates. Here we aimed to characterize some important functional properties in part of the supposed “ventral” pathway in rats. We investigated the functional properties along a progression of five visual areas in awake rats, from primary visual cortex (V1) over lateromedial (LM), latero-intermediate (LI), and laterolateral (LL) areas up to the newly found lateral occipito-temporal cortex (TO). Response latency increased >20 ms from areas V1/LM/LI to areas LL and TO. Orientation and direction selectivity for the used grating patterns increased gradually from V1 to TO. Overall responsiveness and selectivity to shape stimuli decreased from V1 to TO and was increasingly dependent upon shape motion. Neural similarity for shapes could be accounted for by a simple computational model in V1, but not in the other areas. Across areas, we find a gradual change in which stimulus pairs are most discriminable. Finally, tolerance to position changes increased toward TO. These findings provide unique information about possible commonalities and differences between rodents and primates in hierarchical cortical processing.
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Baum, Graham L., Zaixu Cui, David R. Roalf, Rastko Ciric, Richard F. Betzel, Bart Larsen, Matthew Cieslak, et al. "Development of structure–function coupling in human brain networks during youth." Proceedings of the National Academy of Sciences 117, no. 1 (December 24, 2019): 771–78. http://dx.doi.org/10.1073/pnas.1912034117.
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The protracted development of structural and functional brain connectivity within distributed association networks coincides with improvements in higher-order cognitive processes such as executive function. However, it remains unclear how white-matter architecture develops during youth to directly support coordinated neural activity. Here, we characterize the development of structure–function coupling using diffusion-weighted imaging andn-back functional MRI data in a sample of 727 individuals (ages 8 to 23 y). We found that spatial variability in structure–function coupling aligned with cortical hierarchies of functional specialization and evolutionary expansion. Furthermore, hierarchy-dependent age effects on structure–function coupling localized to transmodal cortex in both cross-sectional data and a subset of participants with longitudinal data (n= 294). Moreover, structure–function coupling in rostrolateral prefrontal cortex was associated with executive performance and partially mediated age-related improvements in executive function. Together, these findings delineate a critical dimension of adolescent brain development, whereby the coupling between structural and functional connectivity remodels to support functional specialization and cognition.
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He, Yirong, Debin Zeng, Qiongling Li, Lei Chu, Xiaoxi Dong, Xinyuan Liang, Lianglong Sun, et al. "The multiscale brain structural re-organization that occurs from childhood to adolescence correlates with cortical morphology maturation and functional specialization." PLOS Biology 23, no. 4 (April 1, 2025): e3002710. https://doi.org/10.1371/journal.pbio.3002710.
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From childhood to adolescence, the structural organization of the human brain undergoes dynamic and regionally heterogeneous changes across multiple scales, from synapses to macroscale white matter pathways. However, during this period, the developmental process of multiscale structural architecture, its association with cortical morphological changes, and its role in the maturation of functional organization remain largely unknown. Here, using two independent multimodal imaging developmental datasets aged 6–14 years, we investigated developmental process of multiscale cortical organization by constructing an in vivo multiscale structural connectome model incorporating white matter tractography, cortico–cortical proximity, and microstructural similarity. By employing the gradient mapping method, the principal gradient derived from the multiscale structural connectome effectively recapitulated the sensory-association axis. Our findings revealed a continuous expansion of the multiscale structural gradient space during development, characterized by enhanced differentiation between primary sensory and higher-order transmodal regions along the principal gradient. This age-related differentiation paralleled regionally heterogeneous changes in cortical morphology. Furthermore, the developmental changes in coupling between multiscale structural and functional connectivity were correlated with functional specialization refinement, as evidenced by changes in the participation coefficient. Notably, the differentiation of the principal multiscale structural gradient was associated with improved cognitive abilities, such as enhanced working memory and attention performance, and potentially underpinned by synaptic and hormone-related biological processes. These findings advance our understanding of the intricate maturation process of brain structural organization and its implications for cognitive performance.
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Sotiras, Aristeidis, Jon B. Toledo, Raquel E. Gur, Ruben C. Gur, Theodore D. Satterthwaite, and Christos Davatzikos. "Patterns of coordinated cortical remodeling during adolescence and their associations with functional specialization and evolutionary expansion." Proceedings of the National Academy of Sciences 114, no. 13 (March 13, 2017): 3527–32. http://dx.doi.org/10.1073/pnas.1620928114.
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During adolescence, the human cortex undergoes substantial remodeling to support a rapid expansion of behavioral repertoire. Accurately quantifying these changes is a prerequisite for understanding normal brain development, as well as the neuropsychiatric disorders that emerge in this vulnerable period. Past accounts have demonstrated substantial regional heterogeneity in patterns of brain development, but frequently have been limited by small samples and analytics that do not evaluate complex multivariate imaging patterns. Capitalizing on recent advances in multivariate analysis methods, we used nonnegative matrix factorization (NMF) to uncover coordinated patterns of cortical development in a sample of 934 youths ages 8–20, who completed structural neuroimaging as part of the Philadelphia Neurodevelopmental Cohort. Patterns of structural covariance (PSCs) derived by NMF were highly reproducible over a range of resolutions, and differed markedly from common gyral-based structural atlases. Moreover, PSCs were largely symmetric and showed correspondence to specific large-scale functional networks. The level of correspondence was ordered according to their functional role and position in the evolutionary hierarchy, being high in lower-order visual and somatomotor networks and diminishing in higher-order association cortex. Furthermore, PSCs showed divergent developmental associations, with PSCs in higher-order association cortex networks showing greater changes with age than primary somatomotor and visual networks. Critically, such developmental changes within PSCs were significantly associated with the degree of evolutionary cortical expansion. Together, our findings delineate a set of structural brain networks that undergo coordinated cortical thinning during adolescence, which is in part governed by evolutionary novelty and functional specialization.
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Greiffenstein, Manfred F. "Our Brain as Stone Age Computer." Journal of the International Neuropsychological Society 14, no. 1 (December 14, 2007): 174–76. http://dx.doi.org/10.1017/s1355617708080223.
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Evolutionary Cognitive Neuroscience. 2007. Steven M. Platek, Julian P. Keenan, & Todd K. Shackelford (Eds.). Cambridge, MA: MIT Press, 616 pp., $65.00 (HB)Clinical neuropsychologists are most interested in the ‘what’ of brain function. Neuropsychological assessment requires only a working knowledge of functional localization and the tests best suited to capture that specialization. The ‘why’ of cortical specialization is not necessary for good clinical work. The edited volume Evolutionary Cognitive Neuroscience is entirely devoted to the ‘how’ and ‘why’ of brain specialization based on the fact (not ‘theory’) of natural selection. Editors Steven Platek, Julian Keenan, and Todd Shackelford are well qualified to organize and write this book; they devoted their careers to understanding neuropsychological functions as evolved mechanisms designed to solve recurrent survival and reproduction problems of our evolutionary past. In this view, our brains are Stone Age computers.
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Lloyd-Fox, Sarah, Anna Blasi, Nick Everdell, Clare E. Elwell, and Mark H. Johnson. "Selective Cortical Mapping of Biological Motion Processing in Young Infants." Journal of Cognitive Neuroscience 23, no. 9 (September 2011): 2521–32. http://dx.doi.org/10.1162/jocn.2010.21598.
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How specialized is the infant brain for perceiving the facial and manual movements displayed by others? Although there is evidence for a network of regions that process biological motion in adults—including individuated responses to the perception of differing facial and manual movements—how this cortical specialization develops remains unknown. We used functional near-infrared spectroscopy [Lloyd-Fox, S., Blasi, A., & Elwell, C. Illuminating the developing brain: The past, present and future of functional near-infrared spectroscopy. Neuroscience and Biobehavioral Reviews, 34, 269–284, 2010] to investigate the ability of 5-month-old infants to process differing biological movements. Infants watched videos of adult actors moving their hands, their mouth, or their eyes, all in contrast to nonbiological mechanical movements, while hemodynamic responses were recorded over the their frontal and temporal cortices. We observed different regions of the frontal and temporal cortex that responded to these biological movements and different patterns of cortical activation according to the type of movement watched. From an early age, our brains selectively respond to biologically relevant movements, and further, selective patterns of regional specification to different cues occur within what may correspond to a developing “social brain” network. These findings illuminate hitherto undocumented maps of selective cortical activation to biological motion processing in the early postnatal development of the human brain.
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Deen, Ben, Caspar M. Schwiedrzik, Julia Sliwa, and Winrich A. Freiwald. "Specialized Networks for Social Cognition in the Primate Brain." Annual Review of Neuroscience 46, no. 1 (July 10, 2023): 381–401. http://dx.doi.org/10.1146/annurev-neuro-102522-121410.
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Primates have evolved diverse cognitive capabilities to navigate their complex social world. To understand how the brain implements critical social cognitive abilities, we describe functional specialization in the domains of face processing, social interaction understanding, and mental state attribution. Systems for face processing are specialized from the level of single cells to populations of neurons within brain regions to hierarchically organized networks that extract and represent abstract social information. Such functional specialization is not confined to the sensorimotor periphery but appears to be a pervasive theme of primate brain organization all the way to the apex regions of cortical hierarchies. Circuits processing social information are juxtaposed with parallel systems involved in processing nonsocial information, suggesting common computations applied to different domains. The emerging picture of the neural basis of social cognition is a set of distinct but interacting subnetworks involved in component processes such as face perception and social reasoning, traversing large parts of the primate brain.
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Zhou, Xin, Fumi Katsuki, Xue-Lian Qi, and Christos Constantinidis. "Neurons with inverted tuning during the delay periods of working memory tasks in the dorsal prefrontal and posterior parietal cortex." Journal of Neurophysiology 108, no. 1 (July 1, 2012): 31–38. http://dx.doi.org/10.1152/jn.01151.2011.
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The dorsolateral prefrontal and posterior parietal cortices are two interconnected brain areas that are coactivated in tasks involving functions such as spatial attention and working memory. The response properties of neurons in the two areas are in many respects indistinguishable, yet only prefrontal neurons are able to resist interference by distracting stimuli when subjects are required to remember an initial stimulus. Several mechanisms have been proposed that could account for this functional difference, including the existence of specialized interneuron types, specific to the prefrontal cortex. Although such neurons with inverted tuning during the delay period of a working memory task have been described in the prefrontal cortex, no comparative data exist from other cortical areas that would establish a unique prefrontal role. To test this hypothesis, we analyzed a large database of recordings obtained in the dorsolateral prefrontal and posterior parietal cortex of the same monkeys as they performed working memory tasks. We found that in the prefrontal cortex, neurons with inverted tuning were more numerous and manifested unique properties. Our results give credence to the idea that a division of labor exists between separate neuron types in the prefrontal cortex and that this represents a functional specialization that is not present in its cortical afferents.
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Barrett, Maeve, and Josef Rauschecker. "Elucidating the functional specialization of motion sensitive cortical regions in congenitally blind and sighted adults." Journal of Vision 17, no. 10 (August 31, 2017): 601. http://dx.doi.org/10.1167/17.10.601.
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Mazade, Reece, Jianzhong Jin, Carmen Pons, and Jose-Manuel Alonso. "Functional Specialization of ON and OFF Cortical Pathways for Global-Slow and Local-Fast Vision." Cell Reports 27, no. 10 (June 2019): 2881–94. http://dx.doi.org/10.1016/j.celrep.2019.05.007.
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Sato, Yutaka, Yuko Sogabe, and Reiko Mazuka. "Development of Hemispheric Specialization for Lexical Pitch–Accent in Japanese Infants." Journal of Cognitive Neuroscience 22, no. 11 (November 2010): 2503–13. http://dx.doi.org/10.1162/jocn.2009.21377.
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Infants' speech perception abilities change through the first year of life, from broad sensitivity to a wide range of speech contrasts to becoming more finely attuned to their native language. What remains unclear, however, is how this perceptual change relates to brain responses to native language contrasts in terms of the functional specialization of the left and right hemispheres. Here, to elucidate the developmental changes in functional lateralization accompanying this perceptual change, we conducted two experiments on Japanese infants using Japanese lexical pitch–accent, which changes word meanings with the pitch pattern within words. In the first behavioral experiment, using visual habituation, we confirmed that infants at both 4 and 10 months have sensitivities to the lexical pitch–accent pattern change embedded in disyllabic words. In the second experiment, near-infrared spectroscopy was used to measure cortical hemodynamic responses in the left and right hemispheres to the same lexical pitch–accent pattern changes and their pure tone counterparts. We found that brain responses to the pitch change within words differed between 4- and 10-month-old infants in terms of functional lateralization: Left hemisphere dominance for the perception of the pitch change embedded in words was seen only in the 10-month-olds. These results suggest that the perceptual change in Japanese lexical pitch–accent may be related to a shift in functional lateralization from bilateral to left hemisphere dominance.
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SHIPP, STEWART, and SEMIR ZEKI. "The functional organization of area V2, I: Specialization across stripes and layers." Visual Neuroscience 19, no. 2 (March 2002): 187–210. http://dx.doi.org/10.1017/s0952523802191164.
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We used qualitative tests to assess the sensitivity of 1043 V2 neurons (predominantly multiunits) in anesthetised macaque monkeys to direction, length, orientation, and color of moving bar stimuli. Spectral sensitivity was additionally tested by noting ON or OFF responses to flashed stimuli of varied size and color. The location of 649 units was identified with respect to cycles of cytochrome oxidase stripes (thick-inter-thin-inter) and cortical layer. We used an initial 8-way stripe classification (4 stripes, and 4 “marginal” zones at interstripes boundaries), and a 9-way layer classification (5 standard layers (2–6), and 4 “marginal” strata at layer boundaries). These classes were collapsed differently for particular analyses of functional distribution; the main stripe-by-layer analysis was performed on 18 compartments (3 stripes × 6 layers). We found direction sensitivity only within thick stripes, orientation sensitivity mainly in thick stripes and interstripes, and spectral sensitivity mainly in thin stripes. Positive length summation was relatively more frequent in thick stripes and interstripes, and negative length/size summation in thin stripes. All these “majority” characteristics of stripes were most prominent in layers 3A and 3B. By contrast, “minority” characteristics (e.g. spectral sensitivity in thick stripes; positive size summation in thin stripes) tended to be most frequent in the outer layers, that is, layers 2 and 6. In consequence, going by the four functions tested, the distinctions between stripes were maximal in layer 3, moderate in layer 2, and minimal in layer 6.
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Kuśmierek, Paweł, and Josef P. Rauschecker. "Functional Specialization of Medial Auditory Belt Cortex in the Alert Rhesus Monkey." Journal of Neurophysiology 102, no. 3 (September 2009): 1606–22. http://dx.doi.org/10.1152/jn.00167.2009.
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Responses of neural units in two areas of the medial auditory belt (middle medial area [MM] and rostral medial area [RM]) were tested with tones, noise bursts, monkey calls (MC), and environmental sounds (ES) in microelectrode recordings from two alert rhesus monkeys. For comparison, recordings were also performed from two core areas (primary auditory area [A1] and rostral area [R]) of the auditory cortex. All four fields showed cochleotopic organization, with best (center) frequency [BF(c)] gradients running in opposite directions in A1 and MM than in R and RM. The medial belt was characterized by a stronger preference for band-pass noise than for pure tones found medially to the core areas. Response latencies were shorter for the two more posterior (middle) areas MM and A1 than for the two rostral areas R and RM, reaching values as low as 6 ms for high BF(c) in MM and A1, and strongly depended on BF(c). The medial belt areas exhibited a higher selectivity to all stimuli, in particular to noise bursts, than the core areas. An increased selectivity to tones and noise bursts was also found in the anterior fields; the opposite was true for highly temporally modulated ES. Analysis of the structure of neural responses revealed that neurons were driven by low-level acoustic features in all fields. Thus medial belt areas RM and MM have to be considered early stages of auditory cortical processing. The anteroposterior difference in temporal processing indices suggests that R and RM may belong to a different hierarchical level or a different computational network than A1 and MM.
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Ansari, Daniel, and Bibek Dhital. "Age-related Changes in the Activation of the Intraparietal Sulcus during Nonsymbolic Magnitude Processing: An Event-related Functional Magnetic Resonance Imaging Study." Journal of Cognitive Neuroscience 18, no. 11 (November 2006): 1820–28. http://dx.doi.org/10.1162/jocn.2006.18.11.1820.
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Numerical magnitude processing is an essential everyday skill. Functional brain imaging studies with human adults have repeatedly revealed that bilateral regions of the intraparietal sulcus are correlated with various numerical and mathematical skills. Surprisingly little, however, is known about the development of these brain representations. In the present study, we used functional neuroimaging to compare the neural correlates of nonsymbolic magnitude judgments between children and adults. Although behavioral performance was similar across groups, in comparison to the group of children the adult participants exhibited greater effects of numerical distance on the left intraparietal sulcus. Our findings are the first to reveal that even the most basic aspects of numerical cognition are subject to age-related changes in functional neuroanatomy. We propose that developmental impairments of number may be associated with atypical specialization of cortical regions underlying magnitude processing.
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Kasymov, V., O. Larina, C. Castaldo, N. Marina, M. Patrushev, S. Kasparov, and A. V. Gourine. "Differential Sensitivity of Brainstem versus Cortical Astrocytes to Changes in pH Reveals Functional Regional Specialization of Astroglia." Journal of Neuroscience 33, no. 2 (January 9, 2013): 435–41. http://dx.doi.org/10.1523/jneurosci.2813-12.2013.
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Seo, Hyojung, and Daeyeol Lee. "Cortical mechanisms for reinforcement learning in competitive games." Philosophical Transactions of the Royal Society B: Biological Sciences 363, no. 1511 (October 2008): 3845–57. http://dx.doi.org/10.1098/rstb.2008.0158.
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Game theory analyses optimal strategies for multiple decision makers interacting in a social group. However, the behaviours of individual humans and animals often deviate systematically from the optimal strategies described by game theory. The behaviours of rhesus monkeys ( Macaca mulatta ) in simple zero-sum games showed similar patterns, but their departures from the optimal strategies were well accounted for by a simple reinforcement-learning algorithm. During a computer-simulated zero-sum game, neurons in the dorsolateral prefrontal cortex often encoded the previous choices of the animal and its opponent as well as the animal's reward history. By contrast, the neurons in the anterior cingulate cortex predominantly encoded the animal's reward history. Using simple competitive games, therefore, we have demonstrated functional specialization between different areas of the primate frontal cortex involved in outcome monitoring and action selection. Temporally extended signals related to the animal's previous choices might facilitate the association between choices and their delayed outcomes, whereas information about the choices of the opponent might be used to estimate the reward expected from a particular action. Finally, signals related to the reward history might be used to monitor the overall success of the animal's current decision-making strategy.
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Robison, Christopher L., Theodore Kazan, Rikki L. A. Miller, Tyler Allen, Jason S. Hensley, and Sergios Charntikov. "Topographical Organization of Prefrontal Cortex and Adjacent Areas Projections to the Dorsomedial Caudate–Putamen in Rats: A Retrograde Tracing Study." Brain Sciences 15, no. 4 (April 15, 2025): 398. https://doi.org/10.3390/brainsci15040398.
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The dorsomedial caudate–putamen (dmCPu), a key input structure of the basal ganglia, plays a crucial role in goal-directed behaviors and the transition to habits. The functional specialization of the dmCPu along its anteroposterior axis suggests that distinct prefrontal cortex (PFC) subregions may differentially contribute to these processes. However, the precise topographical organization of PFC and adjacent areas projections to the anterior and posterior dmCPu remains poorly understood. We employed retrograde tracing using Fluoro-Gold to map the projections from PFC subregions and adjacent areas to the anterior and posterior dmCPu in male Sprague Dawley rats. Histological verification and immunohistochemical labeling were conducted to confirm injection sites and neuronal labeling. Quantitative analyses were performed to assess the effects of injection site placement (anterior vs. posterior dmCPu), laterality (ipsilateral vs. contralateral), and cortical subregion on projection density. The posterior dmCPu received significantly higher projection densities than the anterior dmCPu, with a pronounced ipsilateral dominance across all cortical subregions. Among the subregions examined, the cingulate cortex exhibited the highest number of labeled neurons projecting to the dmCPu, with distinct patterns of connectivity between anterior and posterior injection sites. Notably, motor and somatosensory cortical projections were more prominent in the posterior dmCPu, whereas cingulate projections demonstrated robust anteroposterior and lateralized differences. These findings provide a comprehensive map of the topographical organization of cortical inputs to the dmCPu, highlighting differential connectivity patterns that may underlie distinct functional roles in goal-directed and habitual behaviors. This work advances our understanding of corticostriatal circuits and their relevance to adaptive behaviors and neuropsychiatric disorders.
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Masurkar, Arjun V., Chengju Tian, Richard Warren, Isabel Reyes, Daniel C. Lowes, David H. Brann, and Steven A. Siegelbaum. "Postsynaptic integrative properties of dorsal CA1 pyramidal neuron subpopulations." Journal of Neurophysiology 123, no. 3 (March 1, 2020): 980–92. http://dx.doi.org/10.1152/jn.00397.2019.
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The population activity of CA1 pyramidal neurons (PNs) segregates along anatomical axes with different behaviors, suggesting that CA1 PNs are functionally subspecialized based on somatic location. In dorsal CA1, spatial encoding is biased toward CA2 (CA1c) and in deep layers of the radial axis. In contrast, nonspatial coding peaks toward subiculum (CA1a) and in superficial layers. While preferential innervation by spatial vs. nonspatial input from entorhinal cortex (EC) may contribute to this specialization, it cannot fully explain the range of in vivo responses. Differences in intrinsic properties thus may play a critical role in modulating such synaptic input differences. In this study we examined the postsynaptic integrative properties of dorsal CA1 PNs in six subpopulations along the transverse (CA1c, CA1b, CA1a) and radial (deep, superficial) axes. Our results suggest that active and passive properties of deep and superficial neurons evolve over the transverse axis to promote the functional specialization of CA1c vs. CA1a as dictated by their cortical input. We also find that CA1b is not merely an intermediate mix of its neighbors, but uniquely balances low excitability with superior input integration of its mixed input, as may be required for its proposed role in sequence encoding. Thus synaptic input and intrinsic properties combine to functionally compartmentalize CA1 processing into at least three transverse axis regions defined by the processing schemes of their composite radial axis subpopulations. NEW & NOTEWORTHY There is increasing interest in CA1 pyramidal neuron heterogeneity and the functional relevance of this diversity. We find that active and passive properties evolve over the transverse and radial axes in dorsal CA1 to promote the functional specialization of CA1c and CA1a for spatial and nonspatial memory, respectively. Furthermore, CA1b is not a mean of its neighbors, but features low excitability and superior integrative capabilities, relevant to its role in nonspatial sequence encoding.
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Cornette, L., P. Dupont, A. Rosier, S. Sunaert, P. Van Hecke, J. Michiels, L. Mortelmans, and G. A. Orban. "Human Brain Regions Involved in Direction Discrimination." Journal of Neurophysiology 79, no. 5 (May 1, 1998): 2749–65. http://dx.doi.org/10.1152/jn.1998.79.5.2749.
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Cornette, L., P. Dupont, A. Rosier, S. Sunaert, P. Van Hecke, J. Michiels, L. Mortelmans, and G. A. Orban. Human brain regions involved in direction discrimination. J. Neurophysiol. 79: 2749–2765, 1998. To obtain further evidence for the functional specialization and task-dependent processing in the human visual system, we used positron emission tomography to compare regional cerebral blood flow in two direction discrimination tasks and four control tasks. The stimulus configuration, which was identical in all tasks, included the motion of a random dot pattern, dimming of a fixation point, and a tone burst. The discrimination tasks comprised the identification of motion direction and successive direction discrimination. The control tasks were motion detection, dimming detection, tone detection, and passive viewing. There was little difference in the activation patterns evoked by the three detection tasks except for decreased activity in the parietal cortex during the detection of a tone. Thus attention to a nonvisual stimulus modulated different visual cortical regions nonuniformly. Comparison of successive discrimination with motion detection yielded significant activation in the right fusiform gyrus, right lingual gyrus, right frontal operculum, left inferior frontal gyrus, and right thalamus. The fusiform and opercular activation sites persisted even after subtracting direction identification from successive discrimination, indicating their involvement in temporal comparison. Functional magnetic resonance imaging (fMRI) experiments confirmed the weak nature of the activation of human MT/V5 by successive direction discrimination but also indicated the involvement of an inferior satellite of human MT/V5. The fMRI experiments moreover confirmed the involvement of human V3A, lingual, and parietal regions in successive discrimination. Our results provide further evidence for the functional specialization of the human visual system because the cortical regions involved in direction discrimination partially differ from those involved in orientation discrimination. They also support the principle of task-dependent visual processing and indicate that the right fusiform gyrus participates in temporal comparison, irrespective of the stimulus attribute.
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Lu, Liangjian, and James A. Fraser. "Functional consequences of NKCC2 splice isoforms: insights from a Xenopus oocyte model." American Journal of Physiology-Renal Physiology 306, no. 7 (April 1, 2014): F710—F720. http://dx.doi.org/10.1152/ajprenal.00369.2013.
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The Na+-K+-2Cl− cotransporter NKCC2 is exclusively expressed in the renal thick ascending limb (TAL), where it exists as three main splice isoforms, NKCC2B, NKCC2A, and NKCC2F, with the latter two predominating. NKCC2A is expressed in both medullary and cortical TAL, but NKCC2F localizes to the medullary TAL. The biochemical characteristics of the isoforms have been extensively studied by ion uptake studies in Xenopus oocytes, but the functional consequences of alternative splicing remain unclear. We developed a charge-difference model of an NKCC2-transfected oocyte. The model closely recapitulated existing data from ion-uptake experiments. This allowed the reconciliation of different apparent Km values reported by various groups, which have hitherto either been attributed to species differences or remained unexplained. Instead, simulations showed that apparent Na+ and Cl− dependencies are influenced by the ambient K+ or Rb+ bath concentrations, which differed between experimental protocols. At steady state, under bath conditions similar to the outer medulla, NKCC2F mediated greater Na+ reabsorption than NKCC2A. Furthermore, Na+ reabsorption by the NKCC2F-transfected oocyte was more energy efficient, as quantified by JNKCC/ JPump. Both the increased Na+ reabsorption and the increased efficiency were eroded as osmolarity decreased toward levels observed in the cortical TAL. This supports the hypothesis that the NKCC2F is a medullary specialization of NKCC2 and demonstrates the utility of modeling in analyzing the functional implications of ion uptake data at physiologically relevant steady states.
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Vos de Wael, Reinder, Sara Larivière, Benoît Caldairou, Seok-Jun Hong, Daniel S. Margulies, Elizabeth Jefferies, Andrea Bernasconi, Jonathan Smallwood, Neda Bernasconi, and Boris C. Bernhardt. "Anatomical and microstructural determinants of hippocampal subfield functional connectome embedding." Proceedings of the National Academy of Sciences 115, no. 40 (September 24, 2018): 10154–59. http://dx.doi.org/10.1073/pnas.1803667115.
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The hippocampus plays key roles in cognition and affect and serves as a model system for structure/function studies in animals. So far, its complex anatomy has challenged investigations targeting its substructural organization in humans. State-of-the-art MRI offers the resolution and versatility to identify hippocampal subfields, assess its microstructure, and study topographical principles of its connectivity in vivo. We developed an approach to unfold the human hippocampus and examine spatial variations of intrinsic functional connectivity in a large cohort of healthy adults. In addition to mapping common and unique connections across subfields, we identified two main axes of subregional connectivity transitions. An anterior/posterior gradient followed long-axis landmarks and metaanalytical findings from task-based functional MRI, while a medial/lateral gradient followed hippocampal infolding and correlated with proxies of cortical myelin. Findings were consistent in an independent sample and highly stable across resting-state scans. Our results provide robust evidence for long-axis specialization in the resting human hippocampus and suggest an intriguing interplay between connectivity and microstructure.
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Buiatti, Marco, Elisa Di Giorgio, Manuela Piazza, Carlo Polloni, Giuseppe Menna, Fabrizio Taddei, Ermanno Baldo, and Giorgio Vallortigara. "Cortical route for facelike pattern processing in human newborns." Proceedings of the National Academy of Sciences 116, no. 10 (February 12, 2019): 4625–30. http://dx.doi.org/10.1073/pnas.1812419116.
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Humans are endowed with an exceptional ability for detecting faces, a competence that, in adults, is supported by a set of face-specific cortical patches. Human newborns, already shortly after birth, preferentially orient to faces, even when they are presented in the form of highly schematic geometrical patterns vs. perceptually equivalent nonfacelike stimuli. The neural substrates underlying this early preference are still largely unexplored. Is the adult face-specific cortical circuit already active at birth, or does its specialization develop slowly as a function of experience and/or maturation? We measured EEG responses in 1- to 4-day-old awake, attentive human newborns to schematic facelike patterns and nonfacelike control stimuli, visually presented with slow oscillatory “peekaboo” dynamics (0.8 Hz) in a frequency-tagging design. Despite the limited duration of newborns’ attention, reliable frequency-tagged responses could be estimated for each stimulus from the peak of the EEG power spectrum at the stimulation frequency. Upright facelike stimuli elicited a significantly stronger frequency-tagged response than inverted facelike controls in a large set of electrodes. Source reconstruction of the underlying cortical activity revealed the recruitment of a partially right-lateralized network comprising lateral occipitotemporal and medial parietal areas overlapping with the adult face-processing circuit. This result suggests that the cortical route specialized in face processing is already functional at birth.
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S, Saleh Mai, and El-Habashy Hala R. "Study of the Association between Amplitude of Alpha Oscillations at Rest and Scores on the Intellectual Style Inventory." Neuropsychiatry 10, no. 1 (May 16, 2020): 7. https://doi.org/10.5281/zenodo.13596817.
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Background: The Intellectual style inventory (ISI) is a tool for learning style assessment after cortical functional specialization. It introduces four perception styles and four thinking styles that are functionally rooted at the four brain cortical lobes. Alpha activity detected by EEG at rest is known to associate intrinsic neural patterns that differ from one person to another. Aim: The present work aimed to investigate the association between the activities of alpha wave at rest at different brain regions and between the scores obtained by the ISI regarding the different thinking and perception styles. Methods: Participants included in the study reached 36 neurologically healthy females, 16 years of age, and at the same education level. All participants completed the ISI with EEG recording amplitude of alpha oscillations at rest with closed eyes in 19 electrode sites according to 10-20 international system. Results: Significant negative correlations were detected between amplitude of alpha oscillations and scores on the ISI at the different brain regions with lower mean for the groups showing higher scores on the ISI for the front thinking styles and the base perception styles. Conclusion: The ISI is able to introduce a promising conceptual frame and applicable tool for comprehensive investigation of neural patterns relevant to cognitive tasks eminent to psychological functions of learning and information processing.
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Izquierdo, Alicia, and Elisabeth A. Murray. "Combined Unilateral Lesions of the Amygdala and Orbital Prefrontal Cortex Impair Affective Processing in Rhesus Monkeys." Journal of Neurophysiology 91, no. 5 (May 2004): 2023–39. http://dx.doi.org/10.1152/jn.00968.2003.
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The amygdala and orbital prefrontal cortex (PFo) interact as part of a system for affective processing. To assess whether there is a hemispheric functional specialization for the processing of emotion or reward or both in nonhuman primates, rhesus monkeys ( Macaca mulatta) with combined lesions of the amygdala and PFo in one hemisphere, either left or right, were compared with unoperated controls on a battery of tasks that tax affective processing, including two tasks that tax reward processing and two that assess emotional reactions. Although the two operated groups did not differ from each other, monkeys with unilateral lesions, left and right, showed altered reward-processing abilities as evidenced by attenuated reinforcer devaluation effects and an impairment in object reversal learning relative to controls. In addition, both operated groups showed blunted emotional reactions to a rubber snake. By contrast, monkeys with unilateral lesions did not differ from controls in their responses to an unfamiliar human (human “intruder”). Although the results provide no support for a hemispheric specialization of function, they yield the novel finding that unilateral lesions of the amygdala-orbitofrontal cortical circuit in monkeys are sufficient to significantly disrupt affective processing.
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Hutsler, Jeffrey J., and Michael S. Gazzaniga. "The Organization of Human Language Cortex: Special Adaptation or Common Cortical Design?" Neuroscientist 3, no. 1 (January 1997): 61–72. http://dx.doi.org/10.1177/107385849700300116.
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Understanding the neural basis of language is one of the oldest and most difficult pursuits in neuroscience. Despite decades of accumulated data on aphasic subjects with cortical damage, we still know relatively little of how language functions are represented within the neural circuitry of the brain. A major issue of debate is whether language is a species-specific adaptation built into the neocortex, or a by-product of neocortical expansion. Cognitive studies emphasizing the universal nature of language abilities, the consistencies of language structure, and the consistent time course of language development have all indicated that language abilities are innate and must be built into the brain by evolutionary forces. Comparative studies of primates are equivocal since we have little evidence indicating that primate communication is homologous to human language systems. Much of this confusion is related to a lack of information regarding the neural basis of human communication. Recent anatomical data from human brains indicates that left hemisphere regions can have unique types of organization that may be responsible for functional specialization.
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Amil, Adrián F., and Paul F. M. J. Verschure. "Supercritical dynamics at the edge-of-chaos underlies optimal decision-making." Journal of Physics: Complexity 2, no. 4 (December 1, 2021): 045017. http://dx.doi.org/10.1088/2632-072x/ac3ad2.
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Abstract Critical dynamics, characterized by scale-free neuronal avalanches, is thought to underlie optimal function in the sensory cortices by maximizing information transmission, capacity, and dynamic range. In contrast, deviations from criticality have not yet been considered to support any cognitive processes. Nonetheless, neocortical areas related to working memory and decision-making seem to rely on long-lasting periods of ignition-like persistent firing. Such firing patterns are reminiscent of supercritical states where runaway excitation dominates the circuit dynamics. In addition, a macroscopic gradient of the relative density of Somatostatin (SST+) and Parvalbumin (PV+) inhibitory interneurons throughout the cortical hierarchy has been suggested to determine the functional specialization of low- versus high-order cortex. These observations thus raise the question of whether persistent activity in high-order areas results from the intrinsic features of the neocortical circuitry. We used an attractor model of the canonical cortical circuit performing a perceptual decision-making task to address this question. Our model reproduces the known saddle-node bifurcation where persistent activity emerges, merely by increasing the SST+/PV+ ratio while keeping the input and recurrent excitation constant. The regime beyond such a phase transition renders the circuit increasingly sensitive to random fluctuations of the inputs—i.e., chaotic—, defining an optimal SST+/PV+ ratio around the edge-of-chaos. Further, we show that both the optimal SST+/PV+ ratio and the region of the phase transition decrease monotonically with increasing input noise. This suggests that cortical circuits regulate their intrinsic dynamics via inhibitory interneurons to attain optimal sensitivity in the face of varying uncertainty. Hence, on the one hand, we link the emergence of supercritical dynamics at the edge-of-chaos to the gradient of the SST+/PV+ ratio along the cortical hierarchy, and, on the other hand, explain the behavioral effects of the differential regulation of SST+ and PV+ interneurons by acetylcholine in the presence of input uncertainty.
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Zeki, Semir. "The Mystery of Louis Verrey (1854-1916)." Gesnerus 50, no. 1-2 (November 25, 1993): 96–112. http://dx.doi.org/10.1163/22977953-0500102008.
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In 1888, Louis Verrey, a Swiss ophthalmologist, stated emphatically that there is a "centre for the chromatic sense" in the human brain and that it is located in the lingual and fusiform gyri. He did not, however, consider the “colour centre” to be a separate area but a large sub-division of the primary visual cortex. His evidence was quickly dismissed and forgotten. It was not to be taken seriously again until after the experimental discovery of functional specialization in the monkey brain. This paper considers why it is that Verrey did not consider the “colour centre” to be a separate cortical area, distinct from the primary visual cortex, why his evidence was so quickly and effectively dismissed, and why it is that Verrey did not pursue the logic of his findings.
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Zachariou, Valentinos, Roberta Klatzky, and Marlene Behrmann. "Ventral and Dorsal Visual Stream Contributions to the Perception of Object Shape and Object Location." Journal of Cognitive Neuroscience 26, no. 1 (January 2014): 189–209. http://dx.doi.org/10.1162/jocn_a_00475.
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Growing evidence suggests that the functional specialization of the two cortical visual pathways may not be as distinct as originally proposed. Here, we explore possible contributions of the dorsal “where/how” visual stream to shape perception and, conversely, contributions of the ventral “what” visual stream to location perception in human adults. Participants performed a shape detection task and a location detection task while undergoing fMRI. For shape detection, comparable BOLD activation in the ventral and dorsal visual streams was observed, and the magnitude of this activation was correlated with behavioral performance. For location detection, cortical activation was significantly stronger in the dorsal than ventral visual pathway and did not correlate with the behavioral outcome. This asymmetry in cortical profile across tasks is particularly noteworthy given that the visual input was identical and that the tasks were matched for difficulty in performance. We confirmed the asymmetry in a subsequent psychophysical experiment in which participants detected changes in either object location or shape, while ignoring the other, task-irrelevant dimension. Detection of a location change was slowed by an irrelevant shape change matched for difficulty, but the reverse did not hold. We conclude that both ventral and dorsal visual streams contribute to shape perception, but that location processing appears to be essentially a function of the dorsal visual pathway.
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JELINEK, HERBERT F., and GUY N. ELSTON. "DENDRITIC BRANCHING OF PYRAMIDAL CELLS IN THE VISUAL CORTEX OF THE NOCTURNAL OWL MONKEY: A FRACTAL ANALYSIS." Fractals 11, no. 04 (December 2003): 391–96. http://dx.doi.org/10.1142/s0218348x03002270.
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The branching structure of neurones is thought to influence patterns of connectivity and how inputs are integrated within the arbor. Recent studies have revealed a remarkable degree of variation in the branching structure of pyramidal cells in the cerebral cortex of diurnal primates, suggesting regional specialization in neuronal function. Such specialization in pyramidal cell structure may be important for various aspects of visual function, such as object recognition and color processing. To better understand the functional role of regional variation in the pyramidal cell phenotype in visual processing, we determined the complexity of the dendritic branching pattern of pyramidal cells in visual cortex of the nocturnal New World owl monkey. We used the fractal dilation method to quantify the branching structure of pyramidal cells in the primary visual area (V1), the second visual area (V2) and the caudal and rostral subdivisions of inferotemporal cortex (ITc and ITr, respectively), which are often associated with color processing. We found that, as in diurnal monkeys, there was a trend for cells of increasing fractal dimension with progression through these cortical areas. The increasing complexity paralleled a trend for increasing symmetry. That we found a similar trend in both diurnal and nocturnal monkeys suggests that it was a feature of a common anthropoid ancestor.
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Woldorff, Marty G., Chad J. Hazlett, Harlan M. Fichtenholtz, Daniel H. Weissman, Anders M. Dale, and Allen W. Song. "Functional Parcellation of Attentional Control Regions of the Brain." Journal of Cognitive Neuroscience 16, no. 1 (January 2004): 149–65. http://dx.doi.org/10.1162/089892904322755638.
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Recently, a number of investigators have examined the neural loci of psychological processes enabling the control of visual spatial attention using cued-attention paradigms in combination with event-related functional magnetic resonance imaging. Findings from these studies have provided strong evidence for the involvement of a fronto-parietal network in attentional control. In the present study, we build upon this previous work to further investigate these attentional control systems. In particular, we employed additional controls for nonattentional sensory and interpretative aspects of cue processing to determine whether distinct regions in the fronto-parietal network are involved in different aspects of cue processing, such as cue-symbol interpretation and attentional orienting. In addition, we used shorter cue-target intervals that were closer to those used in the behavioral and event-related potential cueing literatures. Twenty participants performed a cued spatial attention task while brain activity was recorded with functional magnetic resonance imaging. We found functional specialization for different aspects of cue processing in the lateral and medial subregions of the frontal and parietal cortex. In particular, the medial subregions were more specific to the orienting of visual spatial attention, while the lateral subregions were associated with more general aspects of cue processing, such as cue-symbol interpretation. Additional cue-related effects included differential activations in midline frontal regions and pretarget enhancements in the thalamus and early visual cortical areas.
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Talati, Ardesheer, and Joy Hirsch. "Functional Specialization within the Medial Frontal Gyrus for Perceptual Go/No-Go Decisions Based on “What,” “When,” and “Where” Related Information: An fMRI Study." Journal of Cognitive Neuroscience 17, no. 7 (July 2005): 981–93. http://dx.doi.org/10.1162/0898929054475226.
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Cortical systems engaged during executive and volitional functions receive and integrate input from multiple systems. However, these integration processes are not well understood. In particular, it is not known whether these input pathways converge or remain segregated at the executive levels of cortical information processing. If unilateral information streams are conserved within structures that serve high-level executive functions, then the functional organization within these structures would predictably be similarly organized. If, however, unilateral input information streams are integrated within executive-related structures, then activity patterns will not necessarily reflect lower organizations. In this study, subjects were imaged during the performance of a “perceptual go/nogo” task for which instructions were based on spatial (“where”), temporal (“when”), or object (“what”) stimulus features known to engage unilateral processing streams, and the expected hemispheric biases were observed for early processing areas. For example, activity within the inferior and middle occipital gyri, and the middle temporal gyrus, during the what and when tasks, was biased toward the left hemisphere, and toward the right hemisphere during the “where” task. We discover a similar lateralization within the medial frontal gyrus, a region associated with high-level executive functions and decision-related processes. This lateralization was observed regardless of whether the response was executed or imagined, and was demonstrated in multiple sensory modalities. Although active during the go/no-go task, the cingulate gyrus did not show a similar lateralization. These findings further differentiate the organizations and functions of the medial frontal and cingulate executive regions, and suggest that the executive mechanisms operative within the medial frontal gyrus preserve fundamental aspects of input processing streams.
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ZIETSCH, BRENDAN, and GUY N. ELSTON. "FRACTAL ANALYSIS OF PYRAMIDAL CELLS IN THE VISUAL CORTEX OF THE GALAGO (OTOLEMUR GARNETTI): REGIONAL VARIATION IN DENDRITIC BRANCHING PATTERNS BETWEEN VISUAL AREAS." Fractals 13, no. 02 (June 2005): 83–90. http://dx.doi.org/10.1142/s0218348x05002829.
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Previously it has been shown that the branching pattern of pyramidal cells varies markedly between different cortical areas in simian primates. These differences are thought to influence the functional complexity of the cells. In particular, there is a progressive increase in the fractal dimension of pyramidal cells with anterior progression through cortical areas in the occipitotemporal (OT) visual stream, including the primary visual area (V1), the second visual area (V2), the dorsolateral area (DL, corresponding to the fourth visual area) and inferotemporal cortex (IT). However, there are as yet no data on the fractal dimension of these neurons in prosimian primates. Here we focused on the nocturnal prosimian galago (Otolemur garnetti). The fractal dimension (D), and aspect ratio (a measure of branching symmetry), was determined for 111 layer III pyramidal cells in V1, V2, DL and IT. We found, as in simian primates, that the fractal dimension of neurons increased with anterior progression from V1 through V2, DL, and IT. Two important conclusions can be drawn from these results: (1) the trend for increasing branching complexity with anterior progression through OT areas was likely to be present in a common primate ancestor, and (2) specialization in neuron structure more likely facilitates object recognition than spectral processing.
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Rosa, Marcello G. P., Juliana G. M. Soares, Tristan A. Chaplin, Piotr Majka, Sophia Bakola, Kimberley A. Phillips, David H. Reser, and Ricardo Gattass. "Cortical Afferents of Area 10 in Cebus Monkeys: Implications for the Evolution of the Frontal Pole." Cerebral Cortex 29, no. 4 (April 13, 2018): 1473–95. http://dx.doi.org/10.1093/cercor/bhy044.
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Abstract Area 10, located in the frontal pole, is a unique specialization of the primate cortex. We studied the cortical connections of area 10 in the New World Cebus monkey, using injections of retrograde tracers in different parts of this area. We found that injections throughout area 10 labeled neurons in a consistent set of areas in the dorsolateral, ventrolateral, orbital, and medial parts of the frontal cortex, superior temporal association cortex, and posterior cingulate/retrosplenial region. However, sites on the midline surface of area 10 received more substantial projections from the temporal lobe, including clear auditory connections, whereas those in more lateral parts received >90% of their afferents from other frontal areas. This difference in anatomical connectivity reflects functional connectivity findings in the human brain. The pattern of connections in Cebus is very similar to that observed in the Old World macaque monkey, despite >40 million years of evolutionary separation, but lacks some of the connections reported in the more closely related but smaller marmoset monkey. These findings suggest that the clearer segregation observed in the human frontal pole reflects regional differences already present in early simian primates, and that overall brain mass influences the pattern of cortico-cortical connectivity.
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Fulcher, Ben D. "Discovering Conserved Properties of Brain Organization Through Multimodal Integration and Interspecies Comparison." Journal of Experimental Neuroscience 13 (January 2019): 117906951986204. http://dx.doi.org/10.1177/1179069519862047.
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The primate cerebral cortex is broadly organized along hierarchical processing streams underpinned by corresponding variation in the brain’s microstructure and interareal connectivity patterns. Fulcher et al. recently demonstrated that a similar organization exists in the mouse cortex by combining independent datasets of cytoarchitecture, gene expression, cell densities, and long-range axonal connectivity. Using the T1w:T2w magnetic resonance imaging map as a common spatial reference for data-driven comparison of cortical gradients between mouse and human, we highlighted a common hierarchical expression pattern of numerous brain-related genes, providing new understanding of how systematic structural variation shapes functional specialization in mammalian brains. Reflecting on these findings, here we discuss how open neuroscience datasets, combined with advanced neuroinformatics approaches, will be crucial in the ongoing search for organization principles of brain structure. We explore the promises and challenges of integrative studies and argue that a tighter collaboration between experimental, statistical, and theoretical neuroscientists is needed to drive progress further.
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Wang, Yezhou, Nicole Eichert, Casey Paquola, Raul Rodriguez-Cruces, Jordan DeKraker, Jessica Royer, Donna Gift Cabalo, et al. "Multimodal gradients unify local and global cortical organization." Nature Communications 16, no. 1 (April 25, 2025). https://doi.org/10.1038/s41467-025-59177-4.
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Abstract Functional specialization of brain areas and subregions, as well as their integration into large-scale networks, are key principles in neuroscience. Consolidating both local and global perspectives on cortical organization, however, remains challenging. Here, we present an approach to integrate inter- and intra-areal similarities of microstructure, structural connectivity, and functional interactions. Using high-field in-vivo 7 tesla (7 T) Magnetic Resonance Imaging (MRI) data and a probabilistic post-mortem atlas of cortical cytoarchitecture, we derive multimodal gradients that capture cortex-wide organization. Inter-areal similarities follow a canonical sensory-fugal gradient, linking cortical integration with functional diversity across tasks. However, intra-areal heterogeneity does not follow this pattern, with greater variability in association cortices. Findings are replicated in an independent 7 T dataset and a 100-subject 3 tesla (3 T) cohort. These results highlight a robust coupling between local arealization and global cortical motifs, advancing our understanding of how specialization and integration shape human brain function.
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Kember, J., P. Patenaude, H. Sweatman, L. Van Schaik, Z. Tabuenca, and X. J. Chai. "Specialization of anterior and posterior hippocampal functional connectivity differs in autism." Autism Research, May 21, 2024. http://dx.doi.org/10.1002/aur.3170.
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AbstractStructural and functional differences in the hippocampus have been related to the episodic memory and social impairments observed in autism spectrum disorder (ASD). In neurotypical individuals, hippocampal–cortical functional connectivity systematically varies between anterior and posterior hippocampus, with changes observed during typical development. It remains unknown whether this specialization of anterior–posterior hippocampal connectivity is disrupted in ASD, and whether age‐related differences in this specialization exist in ASD. We examined connectivity of the anterior and posterior hippocampus in an ASD (N = 139) and non‐autistic comparison group (N = 133) aged 5–21 using resting‐state functional magnetic resonance imaging (MRI) data from the Healthy Brain Network (HBN). Consistent with previous results, we observed lower connectivity between the whole hippocampus and medial prefrontal cortex in ASD. Moreover, preferential connectivity of the posterior relative to the anterior hippocampus for memory‐sensitive regions in posterior parietal cortex was reduced in ASD, demonstrating a weaker anterior–posterior specialization of hippocampal–cortical connectivity. Finally, connectivity between the posterior hippocampus and precuneus negatively correlated with age in the ASD group but remained stable in the comparison group, suggesting an altered developmental specialization. Together, these differences in hippocampal–cortical connectivity may help us understand the neurobiological basis of the memory and social impairments found in ASD.
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Sedigh-Sarvestani, Madineh, and David Fitzpatrick. "What and Where: Location-Dependent Feature Sensitivity as a Canonical Organizing Principle of the Visual System." Frontiers in Neural Circuits 16 (April 12, 2022). http://dx.doi.org/10.3389/fncir.2022.834876.
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Traditionally, functional representations in early visual areas are conceived as retinotopic maps preserving ego-centric spatial location information while ensuring that other stimulus features are uniformly represented for all locations in space. Recent results challenge this framework of relatively independent encoding of location and features in the early visual system, emphasizing location-dependent feature sensitivities that reflect specialization of cortical circuits for different locations in visual space. Here we review the evidence for such location-specific encoding including: (1) systematic variation of functional properties within conventional retinotopic maps in the cortex; (2) novel periodic retinotopic transforms that dramatically illustrate the tight linkage of feature sensitivity, spatial location, and cortical circuitry; and (3) retinotopic biases in cortical areas, and groups of areas, that have been defined by their functional specializations. We propose that location-dependent feature sensitivity is a fundamental organizing principle of the visual system that achieves efficient representation of positional regularities in visual experience, and reflects the evolutionary selection of sensory and motor circuits to optimally represent behaviorally relevant information. Future studies are necessary to discover mechanisms underlying joint encoding of location and functional information, how this relates to behavior, emerges during development, and varies across species.
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Kumar, Sreejan, Theodore R. Sumers, Takateru Yamakoshi, Ariel Goldstein, Uri Hasson, Kenneth A. Norman, Thomas L. Griffiths, Robert D. Hawkins, and Samuel A. Nastase. "Shared functional specialization in transformer-based language models and the human brain." Nature Communications 15, no. 1 (June 29, 2024). http://dx.doi.org/10.1038/s41467-024-49173-5.
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AbstractWhen processing language, the brain is thought to deploy specialized computations to construct meaning from complex linguistic structures. Recently, artificial neural networks based on the Transformer architecture have revolutionized the field of natural language processing. Transformers integrate contextual information across words via structured circuit computations. Prior work has focused on the internal representations (“embeddings”) generated by these circuits. In this paper, we instead analyze the circuit computations directly: we deconstruct these computations into the functionally-specialized “transformations” that integrate contextual information across words. Using functional MRI data acquired while participants listened to naturalistic stories, we first verify that the transformations account for considerable variance in brain activity across the cortical language network. We then demonstrate that the emergent computations performed by individual, functionally-specialized “attention heads” differentially predict brain activity in specific cortical regions. These heads fall along gradients corresponding to different layers and context lengths in a low-dimensional cortical space.
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Wróbel, Paweł P., Hanna Braaß, Benedikt M. Frey, Marlene Bönstrup, Stephanie Guder, Lukas K. Frontzkowski, Jan F. Feldheim, et al. "Cortical microstructure and hemispheric specialization—A diffusion‐imaging analysis in younger and older adults." European Journal of Neuroscience, August 29, 2024. http://dx.doi.org/10.1111/ejn.16518.
Full textAbstract:
AbstractCharacterizing cortical plasticity becomes increasingly important for identifying compensatory mechanisms and structural reserve in the ageing population. While cortical thickness (CT) largely contributed to systems neuroscience, it incompletely informs about the underlying neuroplastic pathophysiology. In turn, microstructural characteristics may correspond to atrophy mechanisms in a more sensitive way. Fractional anisotropy, a diffusion tensor imaging (DTI) measure, is inversely related to cortical histologic complexity. Axial diffusivity and radial diffusivity are assumed to be linked to the density of structures oriented perpendicular and parallel to the cortical surface, respectively. We hypothesized (1) that cortical DTI will reveal microstructural correlates for hemispheric specialization, particularly in the language and motor systems, and (2) that lateralization of cortical DTI parameters will show an age effect, paralleling age‐related changes in activation, especially in the prefrontal cortex. We analysed data from healthy younger and older adult participants (N = 91). DTI and CT data were extracted from regions of the Destrieux atlas. Diffusion measures showed lateralization in specialized motor, language, visual, auditory and inferior parietal cortices. Age‐dependent increased lateralization for DTI measures was observed in the prefrontal, angular, superior temporal and lateral occipital cortex. CT did not show any age‐dependent alterations in lateralization. Our observations argue that cortical DTI can capture microstructural properties associated with functional specialization, resembling findings from histology. Age effects on diffusion measures in the integrative prefrontal and parietal areas may shed novel light on the atrophy‐related plasticity in healthy ageing.
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Hansen, Justine Y., Simone Cauzzo, Kavita Singh, María Guadalupe García-Gomar, James M. Shine, Marta Bianciardi, and Bratislav Misic. "Integrating brainstem and cortical functional architectures." Nature Neuroscience, October 16, 2024. http://dx.doi.org/10.1038/s41593-024-01787-0.
Full textAbstract:
AbstractThe brainstem is a fundamental component of the central nervous system, yet it is typically excluded from in vivo human brain mapping efforts, precluding a complete understanding of how the brainstem influences cortical function. In this study, we used high-resolution 7-Tesla functional magnetic resonance imaging to derive a functional connectome encompassing cortex and 58 brainstem nuclei spanning the midbrain, pons and medulla. We identified a compact set of integrative hubs in the brainstem with widespread connectivity with cerebral cortex. Patterns of connectivity between brainstem and cerebral cortex manifest as neurophysiological oscillatory rhythms, patterns of cognitive functional specialization and the unimodal–transmodal functional hierarchy. This persistent alignment between cortical functional topographies and brainstem nuclei is shaped by the spatial arrangement of multiple neurotransmitter receptors and transporters. We replicated all findings using 3-Tesla data from the same participants. Collectively, this work demonstrates that multiple organizational features of cortical activity can be traced back to the brainstem.