臨床神経学

<シンポジウム(3)―10―2>宇宙医学と神経内科

微小重力環境下における空間識の形成
―スペースシャトル・コロンビア上での実験結果をもとに―

肥塚 泉

聖マリアンナ医科大学耳鼻咽喉科〔〒216―8511 神奈川県川崎市宮前区菅生2―16―1〕

On Earth, humans are constantly exposed to the gravity. During head and body tilts, the otolith organs sense changes in head orientation with respect to the gravitational vertical. These graviceptors also transduce transient linear acceleration generated by translational head motion and centripetal acceleration during rotation about a distant axis. When individuals are rotated at a constant velocity in a centrifuge, they sense the direction of the summed gravitational and centripetal acceleration as the vertical in the steady state. Consequently they experience a roll-tilt of the body when upright and oriented either left-ear-out or right-ear-out. This perception of tilt has been called the somatogravic illusion. Under the microgravity, the graviceptors no longer respond during static tilt of the head or head and body, but they are still activated by linear acceleration. Adaptation to weightlessness early in space flight has been proposed to entail a reinterpretation of the signals from the graviceptors (primarily the otolith organs), so that on return to Earth pitch or roll of the head with respect to the vertical is sensed as foreaft or left-right translation. In this article, formulation of the spatial orientation on the earth and under microgravity was described.
Full Text of this Article in Japanese PDF (292K)

(臨床神経, 52:1318−1320, 2012)
key words:空間識,耳石器,微小重力,宇宙酔い,耳石器における傾斜―移動再解釈説

(受付日:2012年5月25日)