Cortico-cortical feedback from V2 exerts a powerful influence over the visually evoked local field potential and associated spike timing in V1 [article]

Till S Hartmann, Sruti Raja, Stephen G Lomber, Richard T Born
2019 bioRxiv   pre-print
The local field potential (LFP) is generally thought to be dominated by synaptic activity within a few hundred microns of the recording electrode. The sudden onset of a visual stimulus causes a large downward deflection of the LFP recorded in primary visual cortex, known as a visually evoked potential (VEP), followed by rhythmic oscillations in the gamma range (30-80 Hz) that are often in phase with action potentials of nearby neurons. By inactivating higher visual areas that send feedback
more » ... send feedback projections to V1, we produced a large decrease in amplitude of the VEP, and a strong attenuation of gamma rhythms in both the LFP and multi-unit activity, despite an overall increase in neuronal spike rates. Our results argue that much of the recurrent, rhythmic activity measured in V1 is strongly gated by feedback from higher areas, consistent with models of coincidence detection that result in burst firing by layer 5 pyramidal neurons.
doi:10.1101/792010 fatcat:xnzxmxcaqzbqrflpxghsmrtpa4