Academic literature on the topic 'Research. Cognitive Science. Electrophysiology Evoked Potentials'

One of the goals in studying the electrical properties of neurosecretory cells is to relate their electrical activity to the process of secretion. A central question in these studies concerns the role of transmembrane calcium ion flux in the initiation of the secretory event. With regard to the secretory process in pituitary cells, several research groups have addressed this question in vitro using mixed primary anterior pituitary cell cultures or clonal cell lines derived from pituitary tumours. Other workers, including ourselves, have used homogeneous cell cultures derived from the pituitary intermediate lobes of rats to examine the characteristics of voltage-dependent conductances, the contribution of these conductances to action potentials and their role in stimulus-secretion coupling. Pars intermedia (PI) cells often fire spontaneous action potentials whose frequency can be modified by the injection of sustained currents through the recording electrode. In quiescent cells action potentials can also be evoked by the injection of depolarizing current stimuli. At around 20 degrees C these action potentials have a duration of about 5 ms. Although most of the inward current during action potentials is carried by sodium ions, a calcium ion component can be demonstrated under abnormal conditions. Voltage-clamp experiments have revealed that the membrane of these cells contains high-threshold, L-type, Ca2+ channels and low-threshold Ca2+ channels. Since hormone release from PI cells appears not to be dependent on action potential activity but does depend on external calcium ions, it is not clear what role these Ca2+ channels play in stimulus-secretion coupling in cells of the pituitary pars intermedia. One possibility is that the low-threshold Ca2+ channels are more important to the secretory process than the high-threshold channels.

The cerebral cortex forms a sheet of neurons organized into a network of interconnected modules that is highly expanded in humans and presumably enables our most refined sensory and cognitive abilities. The links of this network form a fundamental aspect of its organization, and a great deal of research is focusing on understanding how information flows within and between different regions. However, an often-overlooked element of this connectivity regards a causal, hierarchical structure of regions, whereby certain nodes of the cortical network may exert greater influence over the others. While this is difficult to ascertain non-invasively, patients undergoing invasive electrode monitoring for epilepsy provide a unique window into this aspect of cortical organization. In this review, we highlight the potential for cortico-cortical evoked potential (CCEP) mapping to directly measure neuronal propagation across large-scale brain networks with spatio-temporal resolution that is superior to traditional neuroimaging methods. We first introduce effective connectivity and discuss the mechanisms underlying CCEP generation. Next, we highlight how CCEP mapping has begun to provide insight into the neural basis of non-invasive imaging signals. Finally, we present a novel approach to perturbing and measuring brain network function during cognitive processing. The direct measurement of CCEPs in response to electrical stimulation represents a potentially powerful clinical and basic science tool for probing the large-scale networks of the human cerebral cortex.

Purpose – The purpose of this paper is to utilize the spontaneous brain potentials as an index to quantifying the consumers’ inner emotions, and propose an objective method to obtain the clothing recognitions of consumers by only monitoring brain activities. Design/methodology/approach – Different styles of men’s casual jacket were studied as a case. The research included four phases: first, stimuli samples were constructed by clustering algorithm. Second, self-report for the perception of stimuli samples were recorded by self-assessment manikin. Third, real-time brain potentials while viewing stimuli samples were recorded and analyzed. Finally, the output data were compared with the classical research achievements of visual evoked emotional ERPs to examine the effectiveness. Findings – The results indicated significant difference in main effect of different emotional categories which was identified a corresponding relationship between the emotional trigger and the emotional reaction, of which the early components were the typical components that provided the major physiology characteristics for emotional fashion design. The middle components could be used as the assist reference indexes. The negative stimuli were first noticed because its shorter processing times and larger amplitudes. The comparison confirmed that the proposed method was capable of quantifying cognitive activities of consumers by only monitoring brain activities and then transferred the analyzed data to the design references. Originality/value – The results quantifying the qualities of consumers’ emotional preference for men’ casual jackets based on the neural mechanism of human brain, which could eliminate the systematic biases associated with the uses of words and semantic comprehension in self-report methods. The proposed method may help to enrich and complete the sentimental fashion design for the cognitive experience of consumer oriented. Moreover, it also could be beneficial to optimize design process and improve efficiency and core competitiveness for clothing producers.

In spite of the explosive growth of experimental research in basic neurobiology and neurophysiology of brain components in the past decade, understanding the integrated functioning of the brain remains a significant scientific challenge. Essential for understanding human brain function is the detailed knowledge concerning the spatio-temporal dynamics of neuronal populations and their intricate interactions during cognitive functions. The aim of the present issue is to examine brain dynamics and cognitive functions from a multidisciplinary perspective and to introduce the most recent results in this research frontier. Topics relevant to the special issue include: (i) Modeling brain dynamics at the mesoscopic and macroscopic scales, including dynamical systems with distributed parameters; (ii) Applying tools of discrete mathematics, statistical and quantum physics, network science to describe the dynamics of brains; (iii) Experimental research on brain dynamics from various aspects, including fundamental neurobiology, evoked potentials, functional brain imaging, and cognitive functions; (iv) Clinical neuroscience issues for improved diagnosis of dynamic brain diseases and their potential therapies. This special issue is dedicated to Professor Walter J. Freeman on the occasion of his 80th birthday. Dr. Freeman produced breakthrough contributions to research on brain dynamics over the past five decades. The present issue covers all aspects of neurodynamics, starting from neural populations of high-level cognition and consciousness, as well as philosophical aspects and practical implementations on digital computers and hardware designs.

Human computer interaction (HCI) for completely locked-in patients is a very difficult task. Nowadays, information technology (IT) is becoming an essential part of human life. Patients with completely locked-in state are generally unable to facilitate themselves by these useful technological advancements. Hence, they cannot use modern IT gadgets and applications throughout the lifespan after disability. Advancements in brain computer interface (BCI) enable operating IT devices using brain signals specifically when a person is unable to interact with the devices in conventional manner due to cognitive motor disability. However, existing state-of-the-art application specific BCI devices are comparatively too expensive. This paper presents a research and development work that aims to design and develop a low-cost general purpose HCI system that can be used to operate computers and a general purpose control panel through brain signals. The system is based on steady state visual evoked potentials (SSVEP). In proposed system, these electrical signals are obtained in response of a number of different flickering lights of different frequencies through electroencephalogram (EEG) electrodes and an open source BCI hardware. Successful trails conducted on healthy participants suggest that severely paralyzed subjects can operate a computer or control panel as an alternative to conventional HCI device.

A realização dos Potencias Evocados Auditivos de Longa Latência - PEALL em indivíduos com síndrome de Down - SD podem fornecer dados importantes sobre o processamento cerebral da audição e suas associações necessária para um bom desenvolvimento da linguagem. Analisar latências e amplitudes obtidas no registro dos componentes exógenos e endógeno dos PEALL, em adolescentes com SD, assim como correlacionar os achados entre os gêneros. Foram incluídos no estudo onze adolescentes com SD, que não apresentassem perdas auditivas, sete do gênero feminino e quatro do masculino, com idade mínima de 13 e máxima de 17 anos. Foi realizada avaliação auditiva periférica básica e pesquisa dos PEALL, incluindo o potencial cognitivo (P3). As médias encontradas para as latências dos componentes exógenos P1, N1, P2, N2 foram, respectivamente, de 110,2ms; 180,3ms; 322,2ms e 492,5ms para orelha direita e 100,2ms; 168,3ms; 323,1ms e 497,5ms para orelha esquerda. As amplitudes médias encontradas para P1N1 e N1P2 foram, respectivamente, 15,0μV e 16,0μV para orelha direita e 16,8μV e 18,7μV para orelha esquerda. A média encontrada para a latência da onda P3 foi 651,7ms e amplitude média foi 10,0μV. Houve diferença significativa entre gêneros para a latência de N1 na orelha direita (p=0,020). Na análise das ondas P1, N1, P2, N2 e P3 foi possível observar aumento das latências e amplitudes dentro dos padrões de normalidade. Foi verificada correlação significativa entre gêneros somente para as latências de N1 na orelha direita, tendo o gênero feminino latências superiores. Sugere-se a realização de estudos, que usem os procedimentos de PEALL para avaliar e monitorar, objetivamente, as intervenções e evoluções terapêuticas na SD.Palavra-chave: Audição. Eletrofisiologia. Potenciais Evocados Auditivos.AbstractThe accomplishment of Late Latency Auditory Evoked Potential - LLAEP in individuals with Down syndrome - DS can provide important data from brain processing of hearing and their associations necessary for a good language development. To evaluate latencies and amplitudes obtained from exogenous and endogenous components of LLAEP in teenagers with DS and correlate the findings between genders. This study included 11 teenagers with DS and without hearing loss, seven females and four males with minimum age 13 and maximum 17 years. Hearing evaluation and research of the LLAEP were performed, including cognitive potential (P3). The averages found for the latencies of exogenous components P1, N1, P2, N2 were respectively 110,2ms; 180,3ms; 322,2ms and 492,5ms to right ear and 100,2ms; 168,3ms; 323,1ms and 497,5ms to left ear. The averages found for the amplitudes P1N1 and N1P2 were respectively 15.00μV and 16.0 μV to right ear and 16.8μV and 18.7μV to left ear. The mean found for the latency of the P3 wave was 651.7 ms and mean amplitude 10.0μV. There was a significant difference between genders for N1 latency in the right ear (p=0.020). Analyzing P1, N1, P2, N2 and P3 waves, it was observed increased latencies and amplitudes within the normal range. Significant correlation was observed between genders only for N1 latencies for the right ear, females had higher latencies. It is suggested to carry out studies that use the LLAEP procedures to evaluate and objectively monitor the interventions and therapeutics evolutions in DS.Keywords: Hearing. Electrophysiology. Evoked Potentials, Auditory.

The phenomenon of building-related diseases is attracting much research interest in recent years because of the extent to which it affects people with compromised immune systems, especially children. In this study, we reported the neurological findings in children who attended our Center because of chronic exposure to toxic molds. Clinical neurological and neurobehavioral questionnaires were administered with the cooperation of the children�s parents. The children then underwent a series of neurophysiological tests including electroencephalogram (EEG), brainstem evoked potential (BAEP), visual evoked potential (VEP), and somatosensory evoked potential (SSEP). The results showed high levels of abnormalities in the analysis of the subjective responses derived from the questionnaires. The EEG examination was abnormal in seven out of ten of the patients compared to the controls with only one in ten with episodes of bihemispheric sharp activity. In all the patients, there was frontotemporal theta wave ativity that seemed to indicate diffuse changes characteristic of metabolic encephalopathies. Also, there was highly marked 1 to 3 Hz delta activity that was asymmetrical in the right hemisphere of the brain in three out of ten patients. The waveforms of BAEP showed abnormalities in 90% of the patients with both 15’ and 31’ check sizes compared to none in the controls. There were significant delays in waveform V in a majority of the patients representing dysfunctional cognitive process and conductive hearing loss in both ears. VEP showed clear abnormalities in four in ten of the patients with P100 amplitudes and latencies decreased bilaterally. In all the patients, there was slowing of conduction in the right tibial at an average of 36.9 ms and there was significant decrease in amplitude of response at the proximal stimulation site. Sensory latencies obtained in the median, ulnar, and sural nerves bilaterally showed abnormalities in five out of ten compared to none in the controls. The median, ulnar, and sural sensory potentials were abnormal in six out of ten patients. There was prolongation of the median distal sensory latencies bilaterally at an average of 4.55 ms on the right and an average of 6.10 ms on the left as compared to the ulnars of 2.55 ms bilaterally. There was no abnormality in the controls. These findings represent evidence of diffuse polyneuropathy to which three patients demonstrated borderline slow motor conduction at an average of 41.1 ms. Overall, the objective neurophysiological measurements (EEG, BAEP, VEP, and SSEP) were abnormal, indicating significant neurological deficits in all the patients. Our findings revealed the extent to which toxic molds can affect the neurological and behavioral status of children. Further work should be encouraged in this regard.

Thesis (M.S.)--University of Florida, 2004.
Typescript. Title from title page of source document. Document formatted into pages; contains 60 pages. Includes Vita. Includes bibliographical references.

This chapter is a general introduction to electroencephalography and popular methods used to manipulate EEG in order to elicit markers of sensory, cognitive perception, and behavior. With development of interdisciplinary research, there is increased curiosity among engineers towards biomedical research. Those using signal processing techniques attempt to employ algorithms to the real-life signals and retrieve characteristics of signals such as speech, echo, EEG, among others. The chapter briefs the history of human EEG and goes back to the origins and fundamentals of electrical activity in brain, how this activity reaches the scalp, methods to capture this high temporal activity. It then takes the reader through design methodology that goes behind EEG experiments, general schema for analysis of EEG signal. It describes the concept of early evoked potentials, which are known responses for study of sensory perception and are used extensively in medical science. It moves on to another popular manipulation of EEG technique used to elicit event related potentials.