Brain mapping study of human communication with a functional magnetic resonance imaging technique : identification of specific brain dysfunction in high-function autistic patients

点击翻译按钮获取中文摘要

Autistic disorder, a condition that is characterized by the developmental impairment of language and cognitive function, is understood to be related to deficits in the ability of perceiving emotions and intentions of other persons, which is fundamental to facilitate communication between humans. During the period of financial support from the Ministry of Education, Science, Sports and Culture, we had made attempts to elucidate the brain region (s) which is linked with the pathophysiology of social dysfunctions seen in autistic patients. Paradigms used in the study were tasks of recognition of facial expression of three different emotions (i. e., happy, disgust, and fear). We applied an 'on' and 'off' alternating box car design ; in the 'on' condition, each of three different-emotion tasks was presented and, in 'off' condition, neutral faces presented. We performed scanning for 5 right-handed autistic patients and 9 right-handed healthy controls. Any differences in the brain activity during the tasks between the two groups were tested using non-parametric analysis. On the 'disgust' task, autistic subjects showed significantly lower brain activity in the insula, inferior frontal gyrus, and putamen, on the left side compared with controls. Moreover, hypofunction in the left middle frontal gyrus was revealed in autistic patients on the 'fear' task. However, no different brain activity was detected between the two groups on the 'happy' task. These results suggest that brain regions of the limbic system, particularly on the left side, are associated with the perception of facial expressions and that these areas are related to the biophysiology of the formation of autistic disorder. It is also shown that autistic patients have impairments in the recognition of some, but not all, aspects of facially expressed emotions.