Feedback Control of Hemispheric EEG Alpha

Abstract

Feedback control of alpha activity has made minimal use of controls for disinhibition, oculomotor activity, and non-contingent feedback in the evaluation of alpha-feedback contingencies. The present experiment employed extended alpha training with eyes closed in assessing the contributions of disinhibition and operant contingencies to feedback control of integrated alpha activity. A yoked-cortex control design, in which the cerebral hemisphere generating feedback signals was compared to the contralateral hemisphere, was employed. 7 subjects were given auditory feedback contingent on alpha activity in the left or right hemisphere during five daily training sessions. Changes from respective baseline levels were a function of both disinhibition and contingent feedback stimulation. A significant functional relationship between feedback and alpha activity upon which it was contingent was established for right hemisphere alpha. Results were discussed in terms of feedback-induced activation of the EEG in the contralateral hemisphere during contingent stimulation. It may be easier for subjects to learn control of alpha in the nondominant hemisphere.