The second aspect of neural synchrony, spatial synchronization, has been extensively investigated in numerous animal and human experimental studies involving multi-site registration and topographical mapping of covariations in EEG and evoked potentials in different behavioral paradigms [8]. In particular, animal studies using electrodes implanted in different brain structures demonstrated that synchronization of neural oscillations in different cortical and subcortical structures plays important role in the acquisition of conditioned reflexes and the execution of learned behaviors. Human studies have shown that different cognitive processes and behaviors such as sensory discrimination, perception, imagery, speech, etc. are accompanied by distinct patterns of spatiotemporal organization of cortical oscillations [8]. More recent human studies using advanced recording and analysis techniques [9], [22], [23] provided further evidence that synchronous oscillations in different frequency bands play a crucial role in the dynamic functional integration of brain structures involved in ongoing mental activity. Further evidence for functional significance of neural synchrony measures is provided by studies showing their association with both normal individual differences in cognition, such as general intelligence [24], and neuropsychiatric disorders [25].
