Norman Geschwind's contribution to the understanding of behavioral changes in temporal lobe epilepsy: the February 1974 lecture.

Norman Geschwind catalyzed academic interest in the study of interictal behavioral changes in temporal lobe epilepsy. His contributions to this area comprise a series of 11 articles, chapters, editorials, and commentaries published between 1973 and 1984. This article summarizes, both chronologically and by behavioral topic, Geschwind's contributions and opinions on behavioral changes in temporal lobe epilepsy. A previously unpublished lecture (see article in this issue), "Personality Change in Temporal Lobe Epilepsy," from his course at Harvard Medical School on The Neurology of Behavior (1974), is also quoted to further illustrate his views on specific features of this syndrome. Notably, many of Geschwind's observations and formulations regarding this topic were highly developed in 1974, reflecting his long-standing interest in behavioral changes in epilepsy. Geschwind and his collaborators viewed temporal lobe epilepsy as an important model of behavioral change resulting from a stimulating lesion in the limbic system. This neurobiology accounted for the overarching increased interictal emotionality that underlay the increased religious interests, hypergraphia, increased aggression, increased moral and philosophical concerns, viscosity, and seriousness (lack of humor). Hyposexuality was the exception, although it was consistent with a discharging lesion altering this emotion-driven behavior. Geschwind provided a series of arguments to support the existence of this limbic syndrome and explain why alternative views (e.g., destructive lesion, psychological factors) and arguments against the syndrome's existence are inconsistent with the data.