DYNAMIC FUNCTIONAL COUPLING OF HIGH-RESOLUTION EEG POTENTIALS RELATEDTO UNILATERAL INTERNALLY TRIGGERED ONE-DIGIT MOVEMENTS

Between-electrode cross-covariances of delta (0-3 Hz)- and theta (4-7 Hz)-filtered high resolution EEG potentials related to preparation, in itiation, and execution of human unilateral internally triggered one-d igit movements were computed to investigate statistical dynamic coupli ng between these potentials. Significant (P < 0.05, Bonferroni-correct ed) cross-covariances were calculated between electrodes of lateral an d median scalp regions. For both delta- and theta-bandpassed potential s, covariance modeling indicated a shifting functional coupling betwee n contralateral and ipsilateral frontal-central-parietal scalp regions and between these two regions and the median frontal-central scalp re gion from the preparation to the execution of the movement (P < 0.05). A maximum inward functional coupling of the contralateral with the ip silateral frontal-central-parietal scalp region was modeled during the preparation and initiation of the movement, and a maximum outward fun ctional coupling during the movement execution. Furthermore, for theta -bandpassed potentials, rapidly oscillating inward and outward relatio nships were modeled between the contralateral frontal-central-parietal scalp region and the median frontal-central scalp region across the p reparation, initiation, and execution of the movement. We speculate th at these cross-covariance relationships might reflect an oscillating d ynamic functional coupling of primary sensorimotor and supplementary m otor areas during the planning, starting, and performance of unilatera l movement. The involvement of these cortical areas is supported by th e observation that averaged spatially enhanced delta- and theta-bandpa ssed potentials were computed from the scalp regions where task-relate d electrical activation of primary sensorimotor areas and supplementar y motor area was roughly represented. (C) 1998 Elsevier Science Irelan d Ltd. All rights reserved.