Thilo Kai V, Guerraz Michel, Bronstein Adolfo M, Gresty Michael A
MRC Human Movement and Balance Unit, Institute of Neurology, London, UK.
Exp Brain Res. 2002 Jul;145(2):215-21. doi: 10.1007/s00221-002-1114-9. Epub 2002 May 15.
Large-field motion of the visual environment is a powerful stimulus to induce the perception of contra-directional self-motion in a stationary observer. We investigated the interrelations between horizontal optokinetic nystagmus and subjective states of motion perception under variation of subjects' orientation with respect to gravity. Subjects were tested sitting upright and lying supine, and signalled transitions between object- and self-motion perception whilst viewing an optokinetic stimulus rotating about the subjects' longitudinal axis at a range of angular velocities. Optokinetic stimulation in the supine condition resulted in subjects perceiving a graviceptive conflict and the illusory perception of whole body tilt in a direction opposite to optokinetic stimulus rotation, whereas during upright viewing the axis of stimulus rotation was aligned with the direction of gravity and thus did not result in a conflict or perception of tilt. In both postures, self-motion perception coincided with an increased deviation of mean horizontal gaze position in the perceived direction of heading with a concurrent reduction in optokinetic nystagmus slow-phase gain. Slow-phase gain was also significantly reduced in the supine position as well as at increasing stimulus velocities. The results demonstrate that spontaneous transitions between the perception of object-motion and that of self-motion consistently coincide with spatial attentional and orientational strategies, shifting from passive monitoring to active oculomotor exploration and anticipation.
视觉环境的大视野运动是一种强大的刺激，可在静止观察者中诱发反向自我运动的感知。我们研究了在受试者相对于重力的方向变化时，水平视动性眼震与运动感知主观状态之间的相互关系。受试者分别在直立坐姿和仰卧姿势下接受测试，并在观看以一系列角速度围绕受试者纵轴旋转的视动刺激时，发出物体运动感知和自我运动感知之间的转换信号。仰卧状态下的视动刺激导致受试者感知到重力感受冲突，并产生与视动刺激旋转方向相反的全身倾斜错觉，而在直立观看时，刺激旋转轴与重力方向一致，因此不会导致冲突或倾斜感知。在两种姿势下，自我运动感知都与平均水平注视位置在感知的前进方向上的偏差增加同时出现，同时视动性眼震慢相增益降低。在仰卧位以及刺激速度增加时，慢相增益也显著降低。结果表明，物体运动感知和自我运动感知之间的自发转换始终与空间注意力和定向策略一致，从被动监测转变为主动的眼动探索和预期。
