Effects of sensorimotor EEG feedback training on seizure susceptibility in the rhesus monkey.

Abstract As a follow-up to previous EEG operant conditioning studies in cats both EEG response acquisition and subsequent seizure susceptibility were evaluated in the rhesus monkey. Two groups of four animals each were challenged with a convulsive dose of monomethylhydrazine and both prodrome and seizure characteristics documented with video and polygraphic recordings. One group had previously received 12 weeks of EEG feedback training with food reward provided for the occurrence of rhythmic, central cortical, 12- to 15-cycles/s activity (the sensorimotor rhythm) in the absence of movement and concurrent 8- to 11-cycles/s activity. The second group was studied in another context and received no EEG feedback training. Three of the four training group animals demonstrated a sustained increment of the rewarded response. Compared to controls, the trained group showed a significantly prolonged latency to generalized seizures, fewer total seizures, and enhancement of quiescent behavior during the prodrome. Toxic responses including emesis and motor agitation were comparable among the two groups. These findings support previous observations in cat and man suggesting that enhancement of normal rhythmic EEG patterns in sensorimotor cortex can raise seizure thresholds. A specific alteration of central motor control is proposed as a tentative explanation for this effect.