認知の発達 Development of Cognition

P2-1-195 5，6ヶ月児における自己参照と外部注意に関与する前頭前野活動 Emergence of prefrontal function engaging in self-referential vs. external-focused attention in 5-6 month-old infants ○皆川泰代1,2, 星野英一3, 矢田部清美1, 今福理博4, 佐藤大樹5, 吉村美奈6, 牧敦6 ○Yasuyo Minagawa1,2, Ei-ichi Hoshino3, Kiyomi Yatabe1, Masahiro Imafuku4, Hiroki Sato5, Mina Yoshimuta6, Atsushi Maki6 慶應義塾大学社会学研究科1, 東京工業大学3, 京都大学大学院教育学研究科4, 日立中央研究所5, (株）日立　社会イノベーション・プロジェクト本部6 Graduate School of Human Relations, Keio Univ, Tokyo1, Institut d’Etudes de la Cognition, ENS, France2, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology3, Graduate School of Education, Kyoto University4, Hitachi, Ltd., Central Research Laboratory5, Hitachi, Ltd., Social Innovation Business Project Division6 Functional neuroimaging studies have shown that the medial prefrontal cortex (MPFC) is crucially related to the self-referential mental activity. Specifically, activities of dorsal MPFC increase in tasks involving self-referential mental activity, whereas those decrease in tasks involving externally focused attention, showing a dynamic functional range of this area. This phenomenon is also related to the default mode network which serves as a baseline which is between self-referential and external-focused states. The present study with Near-Infrared Spectroscopy examined whether such prefrontal system is already functional in 5- to 6-month-olds by 2 experiments. Here, we will mainly show the results of the first experiment on prefrontal responses to movie stimuli differing in visual saliency. To measure prefrontal activities of 30 infants, we presented three types of movie: "Peek-a-boo " performed 1) by popular Anime Character (AC) and 2) by human agent and 3) control stimulus with no "Peek-a-boo " by AC. Results showed decreased oxygenated hemoglobin (oxy-Hb) responses in many channels for all the conditions. In particular, amplitude of decrease was stronger for AC "Peek-a-boo" than for any other two conditions. ANOVA test confirmed this tendency in two channels around MPFC and dorsolateral prefrontal cortex. Because of high saliency of AC "Peek-a-boo " and longest behavioral looking time for it, oxy-Hb decrease in two channels was interpreted to attention related decrease, as was observed in adult's fMRI studies in the identical area. In contrast to these decreased activities, experiment 2 found increased MPFC response to infant's name uttered by their mothers but not to other's name and stranger's voice. These results will be discussed in relation to MPFC function for self-referential vs. external-focused attention in the process of human development.

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