High frequency scalp potentials evoked by a reaction time task.
'Bursts' of high frequency (20-80 Hz) extracellular electrical activity are the signature of the brain mechanism mediating recognition of odors in rabbits and cats. To test the hypothesis that a similar mechanism may be functional in man outside the olfactory system, relationships were studied between bursts of 20-150 Hz scalp EEG and parameters of performance during visual reaction time tasks. Specific findings indicated that (1) muscle artifacts were not the primary source of identified EEG bursts, (2) the mechanism which produces the bursts may be similar in both rabbit olfactory bulb and human neocortex, (3) visual task performance may be mediated by the brain areas which produced the bursts, and (4) burst activity varied with changes in performance which may be associated with attention and learning.