Emotional and cognitive characteristics were studied in epileptic patients before and following unilateral left or right temporal lobe resection, and during brain stimulation and intracarotid amytal injection. Physiological events (skin conduc-tance) and electroencephalography (EEG) measures were also monitored during select test performance. The research examined the role of the temporal lobe in establishing limbic sensory associations as a basis for cognition and emotion. 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. In affective spheres, despondency followed pharmacological deactivation of the left hemisphere, whereas euphoria accompanied amytal injection into the right internal carotid. The transient mood state was more common for patients with right temporal lesions with late age at onset of seizure disorder. With neuropsychometric procedures, the patients differed along an introversion-extroversion continuum. Patients presenting an aura of fear are more likely to exhibit maladaptive behaviors. These data suggest that unilateral temporal lobe injury disrupts the normal linkage of cognitive-affective associations mediated by frontal-limbic interaction.
