Neuroscientists have long studied isolated movements such as ankle rotations or finger tapping. From this work we know the basics of how the brain orchestrates simple actions. To hop on one foot-never mind patting your head at the same time -requires calculations relating to spatial awareness, balance, intention and timing, among other things, in the brain's sensorimotor system. In a simplified version of the story, a region called the posterior parietal cortex (toward the back of the brain) translates visual information into motor commands, sending signals forward to motion-planning areas in the premotor cortex and supplementary motor area. These instructions then project to the primary motor cortex, which generates neural impulses that travel to the spinal cord and on to the muscles to make them contract.
At the same time, sensory organs in the muscles provide feedback to the brain, giving the body's exact orientation in space via nerves that pass through the spinal cord to the cerebral cortex. Subcortical circuits in the cerebellum at the brain's core also help to update motor commands based on sensory feedback and to refine our actual motions. What has remained unclear is whether these same neural mechanisms scale up to enable maneuvers as graceful as, say, a pirouette.
To explore that question, we conducted the first neuroimaging study of dance movement, in conjunction with our colleague Michael.Martinez of the University of Texas Health Science Center at San Antonio, using amateur tango dancers as subjects. We scanned the brains of five men and five women using positron-emission tomography, which records changes in cerebral blood flow following changes in brain activity; researchers interpret increased blood flow in a specific region as a sign of greater activity among neurons there. Our subjects lay flat inside the scanner, with their heads immobilized, but they were able to move their legs and glide their feet along an inclined surface. First, we asked them to execute a box step, derived from the basic salida step of the Argentine tango, pacing their movements to the beat of instrumental tango songs, which they heard through headphones. We then scanned our dancers while they flexed their leg muscles in time to the music without actually moving their legs. By subtracting the brain activity elicited by this plain flexing from that recored while they "danced," we were able to home in on brain areas vital to directing the legs through space and generating specific movement patterns.
Brown, S. and Parsons, L.M.(2008) The neuroscience of dance, Scientific American, July, 78-83
【Review課題】
1)運動の神経メカニズムの概要
運動の神経メカニズムの研究は，足首の回転，指の叩きなどの単純行動の研究から，脳が単純行動をどのように調整するかの基礎研究がされてきた．さらに，感覚系運動システムでは，空間認知，バランス，意志，およびタイミングが関係することがわかっている．また，後頭葉では，運動野と補足運動野で運動計画領域に信号を送り，視覚情報を運動指令に変換する．これらの指示は，一次運動野から脊髄を通り，筋肉に神経インパルスを発生させる．同時に筋肉の感覚器は，身体の正確な定位を，脊髄から大脳皮質にフィードバックを与える．小脳の皮質下回路は運動指令を更新して，実際の動きを洗練する．
2)Martinezらの研究の概要
ダンス運動の神経画像処理研究．対象，男性5名，女性5名．