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 (Wada). Physiological events (skin conductance) and 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. In affective spheres, dysphoria 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, the left being more inclined to rate themselves as avoidant, depressed and overly anxious. In contrast, the right temporal patients presented themselves in a more favorable light, but the test profile showed histrionic and aggressive features. 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. Following unilateral temporal lobectomy, physiological hypoarousal was more common with left, and hyperarousal, with right, resections. Changes in activation level may account for the clinical signs of dysphoria and euphoria with left and right brain lesions, respectively.
