title: Cerebral potentials during skilled slow positioning movements.
abstract: Movement-related potentials recorded from the scalp of man were investigated in two skilled positioning tasks, requiring flexions at different joints of the upper extremities. The average response time was approximately 1 sec. Subjects paced their movements themselves and performed without visual control or other external cues. After each trial a delayed visual feedback was given. It was found that the negative potential shift prior to the EMG onset, the 'Bereitschaftpotential', is followed by a persisting negativity during the execution of the action until the target position is reached. Approximately at this point a positive-going deflection appears. This 'goal-directed movement potential' is composed of at least two components: (a) a widely distributed, centrally dominant negativity, and (b) a smaller negative wave over the sensorimotor cortex contralateral to the responding limb. Small variations in response force do not influence the amplitude of the potentials. A negative shift in anticipation of the visual feedback has a topography different from the movement-related potentials, being predominant over the right hemisphere independent of the hand used
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005073:Evoked Potentials, Somatosensory; D005246:Feedback; D006801:Humans; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D009119:Muscle Contraction; D014796:Visual Perception / Q000502:physiology