STIMULUS-SPECIFIC FAST OSCILLATIONS AT ZERO PHASE BETWEEN VISUAL AREAS V1 AND V2 OF AWAKE MONKEY

SYNCHRONIZATION Of fast cortical oscillations (35-90 Hz) has been prop osed as a basis of sensory integration. This hypothesis requires stimu lus specific oscillations that occur synchronously in different cortic al areas of awake animals. Here, we demonstrate the presence of, and p hase-locking between, high amplitude stimulus specific oscillations (5 0-90 Hz) in striate (V1) and extra striate (V2) visual cortex of an aw ake monkey. Oscillations of multiple unit spikes and local field poten tials occurred with an average V1-V2 phase difference near zero. This finding was unexpected because V1 and V2 are thought to be serially ar ranged in the primate's visual processing stream. However, near zero-p hase synchronization among cortical areas might enable fast and effect ive communication via the many reciprocal cortico-cortical connections for processes such as sensory integration.