Gamma-band synchronous oscillations: recent evidence regarding their functional significance.

How do our brains represent distinct objects in consciousness? In order to consciously distinguish between objects, our brains somehow selectively bind together activity patterns of spatially intermingled neurons that simultaneously represent similar and dissimilar features of distinct objects. Gamma-band synchronous oscillations (GSO) of neuroelectrical activity have been hypothesized to be a mechanism used by our brains to generate and bind conscious sensations to represent distinct objects. Most experiments relating GSO to specific features of consciousness have been published only in the last several years. This brief review focuses on a wide variety experiments in which animals, including humans, discriminate between sensory stimuli and make these discriminations evident in their behavior. Performance of these tasks, in humans, is invariably accompanied by conscious awareness of both stimuli and behavior. Results of these experiments indicate that specific patterns of GSO correlate closely with specific aspects of conscious sensorimotor processing. That is, GSO appear to be closely correlated with neural generation of our most paradigmatic cognitive state: consciousness.