Cortical suppressive waves shape the representation of
long-range apparent motion.
Sandrine Chemla, Alexandre Reynaud, Matteo diVolo, Yann
Zerlaut, Laurent Perrinet, Alain Destexhe and
How does the brain link visual stimuli across space and time?
Visual illusions provide an experimental paradigm to study these
processes. When two stationary dots are flashed in close spatial
and temporal succession, human observers experience a percept of
motion. Large spatio-temporal separation challenges the visual
system to keep track of object identity along the apparent motion
path. Here, we utilize voltage-sensitive dye imaging in primary
visual cortex (V1) of the awake monkey to investigate whether
intra-cortical connections within V1 can shape cortical dynamics to
represent the illusory motion. We find that the arrival of the
second stimulus in V1 creates a suppressive wave traveling toward
the retinotopic representation of the first. Computational
approaches show that this suppressive wave can be explained by
recurrent gain control fed by the intra-cortical network and
contributes to precisely encode the expected motion velocity. We
suggest that non-linear intra-cortical dynamics preformat
population responses in V1 for optimal read-out by downstream areas.
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