[Obsessional-type compulsive behavior caused by bilateral circumscribed pallidostriatal necrosis. Encephalopathy caused by a wasp sting].

A previously healthy young man developed encephalopathy after a wasp sting in 1968. Neurological complications included chorea, currently of a minor degree, replaced by buccofacial dyskinesias and compulsive movements. The most disabling consequences were of psychic nature, the patient presenting an unusually marked compulsive activity of an obsessional type. The whole psychic picture however was quite different from that of the usual neurosis, since there was neither anxiety nor doubt, but a mental vacuum contrasting with almost normal intellectual and affective capacities. It was as though there was a loss of the auto-activation system of psychic life, postulated by dynamic psychologists. C.A.T. demonstrated bilateral pallidostriatal necrosis. This suggests that the striatum plays a motor and psychic role. In the field of motor control, its hypoactivity appears to determine not only chorea but dyskinesias similar to tics and compulsive movements. In the psychic field, the striatum appears to play the very general role of an auto-activation system of intellectual and affective life, its deficiency leading to mental activity of a compulsive nature. Improvement in knowledge of striatal biology should clarify not only the basic mechanisms of chorea, but those of tics and obsessions.