Brain activity of finger-movement imitations : Functional mapping of the human brain using fMRI

模倣は、発達における運動学習の基本形式であり、神経科学を含む広範な領域において多くの関心が寄せられている。一方、鏡模倣は解剖模倣よりも実行しやすいが、この基本的特性の神経基盤でさえいまだに明らかではない。そこで本研究では、鏡条件と解剖条件における左右手指運動模倣時の脳活動についてfMRIを用いて比較・検討した。その結果、解剖条件では鏡条件に比較し、後頭側頭葉から前頭前野にかけての広範な領域の活動が認められた。すなわち、解剖条件では意識的に手指運動を認知し、スムーズな運動表出のためのより多くの神経過程が要求されることが示された。また、左手実行において側頭頭頂接合部の賦活が認められたことから、左手実行では指の動きの認知処理に加え、提示された手の意図の無意識的処理を伴う可能性が示された。Imitation is basic and important in motor learning in human development. We have a preference to imitate the actions of others as if looking in a mirror rather than with the anatomically congruent hand. The neural basis of the preference, however, has been unclear until recently. The author investigated with fMRI the brain activity of normal volunteers while executing a-finger-movement imitations with their right and left hands under the specular and anatomic conditions. As the results, statistically significant activations were found in more brain areas (occipito-temporal, parietal and prefrontal cortices, etc.) during anatomic imitation compared with specular imitation, suggesting that anatomic imitation was more related to cognition of hand action and motor simulation based memory. Furthermore, when compared left-hand imitation with right-hand imitation, temporo-parietal junction showed significantly high activation. It was suggested that intention of the moving hand presented was unconsciously processed in addition to the self-movement processing.東京都立保健科学大学, 2004-03, 修士（作業療法学