摂食障害における脳機能画像研究(シンポジウム:摂食障害研究の最前線,2008年,第49回日本心身医学会総会(札幌))  [in Japanese] Brain Imaging Studies in Eating Disorders(Symposium/The Forefront of Eating Disorder Research)  [in Japanese]

肥満体型の視覚刺激や,不快な身体イメージに関連した単語刺激に対する脳の反応性について検討した.健常女性は,男性と比較して,肥満体型刺激で両側前頭野や扁桃体の活動が有意に上昇し,不快な単語刺激で扁桃体を含む左海馬傍回などの有意な活動の上昇を認めた.男女で身体イメージ刺激に対する脳の反応性が異なっており,摂食障害発症率の性差に関与している可能性も示唆された.また,摂食障害患者における病型別比較では,身体イメージに関する不快な単語刺激により,anorexia nervosa restricting type(AN-R)群,anorexia nervosa binge-eating/purging type(AN-BP)群で扁桃体の活動が有意に上昇しており,AN-BPとbulimia nervosa(BN)群で前頭前野の活動が有意に上昇しており,摂食障害の症状,病型と脳の反応性が関連していることが示唆された.

This article describes functional Magnetic Resonance Imaging (fMRI) studies about brain mechanism in eating disorders. We compared the brain activation between men and women during viewing visual stimuli of distorted images of one's own body and processing unpleasant words concerning body image. Women showed significant activation of the bilateral prefrontal cortex and left parahippocampal area including the amygdala upon performing the fat-image. These results suggest that women tend to perceive distorted images of their own bodies by complex cognitive processing of emotion. Women showed amygdala activation while processing unpleasant words concerning body image and perceived these words to be emotionally negative. Furthermore, in the study in eating disorders, significant amygdala activation was shown in AN-R and AN-BP patients but not in BN patients in response to unpleasant body-image words. Significant activation in the medial prefrontal cortex was detected only in AN-BP and BN patients. Our results suggest that activation in the amygdala in response to unpleasant words concerning the body image may be associated with body-image distortion, like extreme weight phobia in AN. Similarly, activation in the medial prefrontal cortex may be associated with abnormal eating behavior, like binge eating/purging. We have identified different brain functions specific to diagnostic subgroups of ED.