Alpha and gamma oscillations characterize feedback and feedforward processing in monkey visual cortex.

ABSTRACT: Cognitive functions rely on the coordinated activity of neurons in many brain regions, but the interactions between cortical areas are not yet well understood. Here we investigated whether low-frequency (?) and high-frequency (?) oscillations characterize different directions of information flow in monkey visual cortex. We recorded from all layers of the primary visual cortex (V1) and found that ?-waves are initiated in input layer 4 and propagate to the deep and superficial layers of cortex, whereas ?-waves propagate in the opposite direction. Simultaneous recordings from V1 and downstream area V4 confirmed that ?- and ?-waves propagate in the feedforward and feedback direction, respectively. Microstimulation in V1 elicited ?-oscillations in V4, whereas microstimulation in V4 elicited ?-oscillations in V1, thus providing causal evidence for the opposite propagation of these rhythms. Furthermore, blocking NMDA receptors, thought to be involved in feedback processing, suppressed ? while boosting ?. These results provide new insights into the relation between brain rhythms and cognition.

SUBMITTER: van Kerkoerle T 

PROVIDER: S-EPMC4210002 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature