NO-GO ACTIVITY IN THE FRONTAL ASSOCIATION CORTEX OF HUMAN-SUBJECTS

'No-go potential', specific to the no-go reaction in go/no-go reaction -time hand movement with discrimination between different colour light stimuli, was recorded with electrodes chronically implanted in the pr efrontal cortex of monkeys. Similar potentials were widely distributed over frontal-parietal parts of the human scalp on the same no-go reac tion. In this report, MEG measurement was made over the scalp of five healthy subjects in order to localize current sources responsible for the scalp potential. We found in- and outflow of magnetic fields over the dorsolateral frontal parts of the head, contra- and ipsilateral to the operant hand. These magnetic fields were most reasonably interpre ted to be due to current dipoles localized in the dorsolateral parts o f frontal lobes in both contra- and ipsilateral hemispheres, presumabl y in the prefrontal-premotor areas. No-go decision and subsequent supp ression of voluntary movements are suggested to be one of the function al features of the human frontal association cortex, as in the case of monkeys.