BIHIPPOCAMPAL DAMAGE WITH EMOTIONAL DYSFUNCTION - IMPAIRED AUDITORY RECOGNITION OF FEAR

A right-handed man developed a sudden transient, amnestic syndrome ass ociated with bilateral hemorrhage of the hippocampi, probably due to U rbach-Wiethe disease. In the 3rd month, despite significant hippocampa l structural damage on imaging, only a milder degree of retrograde and anterograde amnesia persisted on detailed neuropsychological examinat ion. On systematic testing of recognition of facial and vocal expressi on of emotion, we found an impairment of the vocal perception of fear, but not that of other emotions, such as joy, sadness and anger. Such selective impairment of fear perception was not present in the recogni tion of facial expression of emotion. Thus emotional perception varies according to the different aspects of emotions and the different moda lity of presentation (faces versus voices). This is consistent with th e idea that there may be multiple emotion systems. The study of emotio nal perception in this unique case of bilateral involvement of hippoca mpus suggests that this structure may play a critical role in the reco gnition of fear in vocal expression, possibly dissociated from that of other emotions and from that of fear in facial expression. In regard of recent data suggesting that the amygdala is playing a role in the r ecognition of fear in the auditory as well as in the visual modality t his could suggest that the hippocampus may be part of the auditory pat hway of fear recognition.