title: Involvement of the mirror neuron system in blunted affect in schizophrenia.
abstract: Blunted affect is a relatively enduring schizophrenic symptom and its presence brings about poor functioning and outcomes. Functional impairment in the mirror neuron system which is involved in both motor execution and imitation may be a neural basis of blunted affect, but it is not proved yet. Fifteen patients with schizophrenia and 16 healthy controls performed the facial expression task during functional magnetic resonance imaging. The task was to reproduce facial expressions in response to the face or word stimuli for happiness, sadness, and meaningless expression. Brain activities during facial expressions in patients compared with controls and their relationship with affective flattening were analyzed. Compared to controls, patients exhibited decreased activity in the widespread dorsal frontal regions and increased activity in the ventral frontal and subcortical regions. Patients also demonstrated significant negative correlation of the severity of affective flattening with activities in the mirror neuron system, such as the premotor cortex, motor cortex, and inferior parietal lobule. Emotional expression in patients with schizophrenia may be related to hypoactivity of the dorsal system and hyperactivity of the ventral system. An imbalance of these two systems may contribute to blunted affect. Directly addressing blunted affect using emotional expression provides a new perspective that functional disturbance of the mirror neuron system may play an important role in manifestation of blunted affect in schizophrenia.
authors.affiliation: Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea; Department of Psychiatry, Bundang Jesaeng Hospital, Seongnam Gyeonggi, Republic of Korea.
authors.forename: Jung Suk
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Chun
authors.affiliation: Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Sang Young
authors.initials: SY
authors.lastname: Yoon
authors.affiliation: Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea; Department of Radiology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Hae-Jeong
authors.initials: HJ
authors.lastname: Park
authors.affiliation: Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea; Department of Psychiatry, Yonsei University College of Medicine, Seoul, Republic of Korea. Electronic address: jaejkim@yonsei.ac.kr.
authors.forename: Jae-Jin
authors.initials: JJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000098:blood supply / Q000473:pathology*; D004644:Emotions / Q000502:physiology*; D005149:Facial Expression; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D059167:Mirror Neurons / Q000473:pathology*; D009434:Neural Pathways / Q000098:blood supply; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual; D010775:Photic Stimulation; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000150:complications / Q000473:pathology*
chemical_list: D010100:Oxygen
keywords: Blunted affect; Facial expressions; Mirror neuron system; Schizophrenia; fMRI