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CiNet第11回HHSセミナーがCiNet棟で開催されます。東大から坂井克之先生をお招きして、Neurobiology of Human Cognitionと題してお話していただきます。

CiNet, the 11th HHS seminar

Date/Time: April 19 (Fri), 2013/ 16:00-17:00
Place: CiNet Building 1F Conference Hall
http://www.fbs.osaka-u.ac.jp/jpn/general/images/FBSSuitaMap-jpn-2013.jpg
(Build. No. 11)

Title: Neurobiology of Human Cognition

Speaker: Dr. Katsuyuki Sakai
Department of Cognitive Neuroscience,
Graduate School of Medicine,
The University of Tokyo

Abstract: Most of the studies to date on human brain functions rely on brain mapping techniques with which one examines how regional activation changes depending on various cognitive demands. Activation in a given region, however, is the result of inputs from other regions, and is also the cause of changes in activation in other regions. Therefore, in order to understand how the brain works, it is essential to examine neural signal transmission across regions. To this end, we have recently developed a technique of concurrent transcranial magnetic stimulation (TMS) and EEG recording and examined the efficacy of signal transmission across cortical regions. We found that the pattern of signal transmission from the prefrontal cortex is i) modulated in task-dependent manners, ii) modulated in history-dependent manners, iii) associated with behavioral performance, iv) distinct from the pattern of regional activation. We also found that the signal transmission v) is modulated in a direction-specific manner between prefrontal and parietal regions, and vi) changes in a temporally dynamic manner during cognitive processes. My idea is that synaptic mechanisms underlie these dynamic and persistent natures of neural signal transmission within the neural network. To test this idea, we are currently developing techniques i) to estimate synaptic efficacy using biophysical cortical models, ii) to examine the physiological basis of the changes in signal transmission using subdural and depth electrodes in epileptic patients, and iii) to manipulate the efficacy of signal transmission by artificially inducing synaptic plasticity. The goal is to measure and manipulate synaptic functions in the human brain by adapting techniques that have been used in animal and brain slice studies. These studies, I believe, will elucidate the neurobiological mechanisms of the human brain and cognitive functions, and promote sharing of ideas and knowledge between researchers working at different levels of neural organization.

References:
  • Akaishi et al. Stimulation of the frontal eye field reveals persistent effective connectivity after controlled behavior. Journal of Neuroscience 30:4295-4305, 2010.
  • Morishima et al. Task-specific signal transmission from prefrontal cortex in visual selective attention. Nature Neuroscience 12:85-91, 2009.
  • Sakai. Task set and prefrontal cortex. Annual Review of Neuroscience 31:219-245, 2008.