International journal of psychophysiology : official journal of the International Organization of Psychophysiology
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Int J Psychophysiol · Jun 1997
ReviewPhase correlation among rhythms present at different frequencies: spectral methods, application to microelectrode recordings from visual cortex and functional implications.
In classical EEG analysis rhythms with different frequencies occurring at separable regions and states of the brain are analysed. Rhythms in different frequency bands have often been assumed to be independent and their occurrence was interpreted as a sign of different functional operations. Independence has scarcely been proved because of conceptual and computational difficulties. ⋯ Our suggestions include: (1) visual feature linking across different temporal and spatial scales provided by coherent oscillations at high and low frequencies; (2) linking of visual cortical representations (high frequencies) to subcortical centers (low frequencies) like the thalamus and hippocampus; and (3) temporal segmentation of the sustained stream of incoming visual information into separate frames at different temporal resolutions in order to prevent perceptual smearing due to shifting retinal images. These proposals are, at present, merely speculative. However, they can, in principle, be proved by microelectrode recordings from trained behaving animals.