Cortical potentials at the frequency of absolute wrist velocity become phase-locked during slow sinusoidal tracking movements.
A 1-Hz rhythmic event-related potential was recorded at the scalp during performance of a 0.5-Hz tracking task. At cortical motor areas, negative peaks occurred 10-20 ms after peak tracking speeds. Analysis of single sweeps suggested that EEG phase was reset at initiation of the tracking motion and then maintained a constant relationship to wrist speed until task completion. Frequency analysis indicated that rhythm appearance in the averaged potential was predominantly due to phase-locking, because there was no tracking-related increase in 1 Hz amplitude within individual sweeps. While tracking, phase-locking was present over bilateral parieto-occipital and frontal regions, with a slight predominance at the contralateral frontal region. When subjects observed the target motion, phase-locking was localized to parieto-occipital regions. We suggest mental processes such as visual processing, visuomotor coordination and real-time motor planning are reflected in the pacing of localized cortical potential fluctuations.
O'Suilleabhain
P E
PE
University of Texas Southwestern Medical Center, Department of Neurology, Dallas 75235-9036, USA.
Lagerlund
T D
TD
Matsumoto
J Y
JY
D000328:Adult; D001921:Brain / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D007839:Functional Laterality; D006257:Head; D006801:Humans; D007103:Immobilization; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009068:Movement / Q000502:physiology; D012535:Scalp / Q000294:innervation; D014955:Wrist Joint / Q000294:innervation / Q000502:physiology*