Seminar Series

Visual search and the parietal cortex (and the frontal eye fields and the extrastriate cortex and the primary visual cortex)

There seems to be a consensus regarding the role of the parietal cortex in visual search, partly based on the role of parietal cortex in spatial attention, partly based on its role in eye movements and partly based on studies of patients with damage to the parietal cortex. I want to argue that the consensus is wrong and that several other brain areas may carry out some of the functions attributed to the parietal cortex. I also want to argue that the parietal cortex is a poor candidate for the some of the functions with which it is has been attributed. Based on studies using transcranial magnetic stimulation (the method will be demonstrated) I will show that the frontal eye fields are important for visual search, that extrastriate areas are responsible for the feature analysis and that late back-projections to V1 are critical for some functions often attributed to higher visual areas. Finally, I will try to suggest that the way in which visual search is studied in the lab is possibly not very informative about how one carries out search in the real world.