Electroencephalographic spectra and reaction time in disorders of higher nervous function.

Cerebral electrical abnormalities associated with variability of attention and responsivity were sought in individuals with schizophrenia and epilepsy. Experimental and control subjects were given stimulus-response tasks, and average power spectra for brief electroencephalographic epochs preceding responses of short and long latency were compared. Spectra that precede long-latency or erroneous responses resemble the "ramp" configuration of spectra computed from scalp electroencephalograms for 1-second epochs triggered by (time-locked to) focal subcortical spikes.