Rhythms in Perception: oscillatory patterns of colour-to-form filling-in

Neuronal oscillations are now generally believed to underlie variations in perception, particularly under constant environmental input. In recent years there has been an increase in interest into the influence of the alpha frequency band on visual perception. Alpha has been found to strongly correlate with basic aspects of visual perception. The current study aims to investigate if alpha also has a role in the underlying processing of more complex visual processing through examining patterns of the filling-in effect over different stimulus onset delays. It was found that colour-to-form filling-in occurred in a cyclic pattern at a frequency of 27Hz, corresponding with high beta/low gamma. Such higher frequencies therefore appear to have more importance for complex featural integration. Activity at this frequency may mediate communication between distributed neuronal assemblies leading to integrated perception.