Charles M. Gray

17 juin 2016

Joint seminar INT-INS

Dept. of Cell Biology & Neuroscience, Montana State University, Bozeman, Montana, USA

Distributed cortico-cortical interactions underlying visual working memory

invité par Andrea Brovelli & Demian Battaglia (INS)

Abstract : Cognitive processes, such as working memory, engage large neuronal populations spanning widespread cortical and subcortical areas. To further understand the task dependence, and the spectral, temporal and spatial organization of these activity patterns, we designed a large-scale recording system that enables the chronic implantation of 256 independently movable microelectrodes spanning an entire cerebral hemisphere in macaque monkeys. We implanted this system in two animals and recorded neuronal activity from more than 60 separate cortical areas while the animals performed an object-based, visual delayed match-to-sample task and a set of control tasks. Analysis of the unit activity revealed a widespread distribution of task dependent and content specific cellular responses, concentrated in multiple areas of the prefrontal, premotor, posterior parietal and visual cortices. Analysis of the local field potential (LFP) revealed striking regional variations in the distribution of spectral power and coherence. These signals displayed a mixture of increases and decreases in magnitude during the task. Coherence and phase-locking analyses revealed widespread, task-dependent patterns of correlated activity that varied in frequency and phase. These studies provide the first analysis of the temporal and spectral patterns of cortical neuronal activity spanning a cerebral hemisphere in macaque monkeys performing a cognitive task.

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