Stimulus-specific fast oscillations at zero phase between visual areas V1 and V2 of awake monkey

TLDR

Fast cortical oscillations (35–90 Hz) are proposed to underlie sensory integration, requiring stimulus‑specific synchrony across awake cortical areas. We observed stimulus‑specific 50–90 Hz oscillations in V1 and V2 of an awake monkey that were phaselocked with an average near‑zero V1–V2 phase difference, suggesting that zero‑phase synchrony could facilitate rapid communication despite the serial arrangement of these visual areas.

Abstract

Synchronization of fast cortical oscillations (35–90 Hz) has been proposed as a basis of sensory integration. This hypothesis requires stimulus specific oscillations that occur synchronously in different cortical areas of awake animals. Here, we demonstrate the presence of, and phaselocking between, high amplitude stimulus specific oscillations (50–90 Hz) in striate (V1) and extra striate (V2) visual cortex of an awake monkey. Oscillations of multiple unit spikes and local field potentials occurred with an average V1–V2 phase difference near zero. This finding was unexpected because V1 and V2 are thought to be serially arranged in the primate's visual processing stream. However, near zero-phase synchronization among cortical areas might enable fast and effective communication via the many reciprocal cortico–cortical connections for processes such as sensory integration.