SUPPRESSION OF EEC RHYTHMIC FREQUENCIES DURING SOMATO-MOTOR AND VISUO-MOTOR BEHAVIOR

In a previous study of simulated vehicle performance we found that sta tionary visual attention and body movements alone produced selective e ffects on topographic EEG frequency patterns. In the present study we focus on an expanded set of these task components. EEG, EOG and ECG da ta were recorded from 21 subjects during instructed driving movements and during visual scanning tasks ranging from a stationary to a rapidl y moving simulated driving display. Spectral analysis was calculated o n ten 2-Hz, partially overlapped frequency bands between 6 and 17 Hz. Body movements produced a selective bilateral suppression of 11-15 Hz activity localized to medial somatosensory cortex, while both slow and rapid visual scanning tasks produced a similar bilateral suppression of 11-15 Hz activity localized to temporo-parietal sites. A generalize d suppression of 7-11 Hz activity was also found during the fastest vi sual scanning task. There were no significant differences in ECG betwe en tasks. Other human and animal findings consistent with these functi onal observations are discussed.