From Jekyll to Hyde after limbic subthalamic nucleus infarction

Abstract

Strokes affecting the subthalamic nucleus (STN) characteristically produce hemichorea.1 Although the STN is an important component of the motor circuit of the basal ganglia, its function in association with the limbic circuit is less well-known. We herein describe a patient who showed behavioral changes after STN infarction. Using multimodal imaging studies, we attempted to elucidate evidence of disconnection of dopaminergic fibers from STN to the ventral caudate nucleus (VCN) and orbitofrontal cortex (OFC), which may explain the patient's symptoms. ### Case report. A 49-year-old ambidextrous male office worker suddenly developed dizziness, dysarthria, and gait disturbance. An interview with his family members revealed that he used to be a taciturn and calm person, and did not have any psychiatric illnesses before the stroke. After this event, his family and friends noticed that he became loquacious, irritable, impulsive, and, occasionally, violent. For instance, his colleague once observed him driving his car violently up onto the pedestrian sidewalk. He also quarreled frequently over trivial issues with his family members and colleagues. On admission 2 months later, he was alert without aphasia. He showed ptosis in the left eye and mild ataxia in the right leg. He was talkative, stentorian, and frequently interrupted the interview with irrelevant issues. Neuropsychological evaluation disclosed memory impairment including encoding deficit in …