Perception and judgment with cognitive and emotional tasks were monitored by electroencephalographic (EEG) activity recorded from left and right brain regions, of patients following unilateral temporal lobectomy. EEG disturbances in brain-behavior relations in neuropsychiatric patients were also evaluated, relating left and right brain dysfunctioning to maladaptive ideative and emotional reactions, respectively. With temporal lobectomy patients, preliminary results indicate that electrographic shifts in frequency-amplitude differed in that right temporal patients showed greater responsivity to pleasant and horrific materials, and less so while applying cognitive strategies to deal with imaginary emotionally charged situations. The converse was true with left temporal patients who generated greater activity while intellectually resolving emotional tasks. These data underscore the dual cognitive and emotional roles of the limbic system in modulating human behavior. Left brain stimulation (indwelling flap electrodes) of posterior sites, produced storage and retrieval memory errors with anterior and posterior, temporal sites, respectively. Stimulation of frontal cortex produced defects suggestive of mechanisms that collate immediate and long-term plans. There was a dissociation between' aphasia and amnesia with inferior, posterior temporal stimulation, emphasizing the importance of this region to retrieval from episodic memory registers. With right brain stimulation, paralinguistic disturbances were produced in prosody, and there were errors in interpreting ambiguous statements, and in pattern discrimination and recognition.