The role of neural synchrony in visual processing and perception:

Rhythmic activity of neuronal ensembles has been proposed to play an important role in cognitive functions such as attention, perception, working memory and memory encoding. Evidence is mounting that disruption of synchronization, particularly in the gamma- (25-100 Hz) and beta (13-25 Hz) frequency band, is associated with cognitive deficits as seen in schizophrenia, autism, Alzheimer disease and Parkinson's disease. The rhythmic activity facilitates synchronization of neurons despite various conduction delays between spatially distant neuron pools, and appears to be crucial to coordinate functional connectivity in a task dependent manner]. Although several studies have investigated potential perceptual and cognitive functions of neuronal short- and long-range synchronization, the mechanisms of their in vivo generation, maintenance and control are still poorly understood. Despite substantial support for the role of oscillatory activity in cognitive functions, our recent data suggest that increased gamma oscillations are not a hallmark of cognitive functions in all cortical areas or under all task conditions.

          Chalk et al. 2011, Neuron

Recording electrical signals simultaneously from many neurons in awake behaving monkeys I investigate the role of synchrony amoung neurons in information processing and perception. Although a  considerable number of neurons synchronize their activity at the millisecond timescale, our data do not indicate that this synchronization is related to perceptual binding

However, synchronous activity is likely to play a role in detection of weak stimuli.  A short pulse of activity (most likely to occur simultaneously in main neurons) is the best determinant of reaction times on a trial by trial basis in contrast perception near threshold.

Thiele, Hoffmann, EBR 2008