Higher cognitive functions require the coordination of large assemblies of

spatially distributed neurons in ever changing constellations. It is

proposed that this coordination is achieved through temporal coordination

of oscillatory activity in specific frequency bands. Since there is no

supra-ordinate command centre in the brain, the respective patterns of

synchronous activity self-organize, which has important implications on

concepts of intentionality and top down causation. Evidence will be

provided that synchronisation supports response selection by attention,

feature binding, subsystem integration, short-term memory, flexible

routing of signals across cortical networks and access to the work-space

of consciousness. The precision of synchronisation is in the millisecond

range, suggesting the possibility that information is encoded not only in

the co-variation of discharge rates but also in the precise timing of

individual action potentials. This could account for the high speed with

which cortical circuits can encode and process information. Recent studies

in schizophrenic patients indicate that this disorder is associated with

abnormal synchronisation of oscillatory activity in the high frequency

range (beta and gamma). This suggests that some of the cognitive deficits

characteristic for this disease result from deficient binding and

subsystem integration.