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SUMMARY:&quot\;The visual cortex as a cognitive blackboard&quot\; - Pieter
  Roelfsema\, Netherlands Institute for Neuroscience
DTSTART:20170123T163000Z
DTEND:20170123T180000Z
UID:TALK70639@talks.cam.ac.uk
CONTACT:Lyn Dakin
DESCRIPTION:Most theories hold that early visual cortex is responsible for
  the local analysis of simple features while cognitive processes take plac
 e in higher areas of the parietal and frontal cortex. However\, these theo
 ries are not undisputed because there are findings that implicate early vi
 sual cortex in visual cognition - in tasks where subjects reason about wha
 t they see. Are these cognitive effects in early visual cortex an epipheno
 menon or are they functionally relevant for these mental operations?\n\nI 
 will discuss new evidence supporting the hypothesis that the modulation of
  activity in early visual areas has a causal role in cognition. The modula
 tory influences allow the early visual cortex to act as a multiscale cogni
 tive blackboard for read and write operations by higher visual areas\, whi
 ch can thereby efficiently exchange information. This blackboard architect
 ure explains how the activity of neurons in the early visual cortex contri
 butes to scene segmentation and working memory\, and relates to the subjec
 t’s inferences about the visual world. \n\nI will illustrate these ideas
  with a contour grouping task and a working memory task. In the contour-gr
 ouping task\, subjects see a number of curves and it is their task to ment
 ally trace one curve (target curve) and to ignore the other curves (distra
 ctor curves). We recorded neuronal activity in the different layers of V1 
 of monkeys during this task and we also recorded neuronal activity in area
  V3 of a human patient\, implanted with electrodes for the treatment of ep
 ilepsy. When the monkey or human subjects mentally trace a target curve\, 
 the representation of this curve is enhanced in early visual cortex. In th
 e monkeys\, we observed a characteristic profile of top-down inputs in the
  superficial layers and layer 5 causing an increase in the firing rates in
  feedback recipient layers. We also observed working memory signals in are
 a V1. These results provide new insights in the role of early visual corte
 x as a cognitive blackboard that supports the implementation of mental pro
 grams.\n
LOCATION:The Hodgkin Huxley Seminar Room\, Department of Physiology Develo
 pment and Neuroscience
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