Department of Neurology, University Hospital Zurich, CH-8091 Zurich, Switzerland.
J Neurosci. 2011 Jul 6;31(27):9991-7. doi: 10.1523/JNEUROSCI.0064-11.2011.
When humans are accelerated along the body vertical, the right and left eyes show oppositely directed torsional modulation (cyclovergence). The origin of this paradoxical response is unknown. We studied cyclovergence during linear sinusoidal vertical motion in healthy humans. A small head-fixed visual target minimized horizontal and vertical motion of the eyes and therefore isolated the torsional component. For stimuli between 1 and 2 Hz (near the natural range of head motion), the phase of cyclovergence with respect to inertial acceleration was 8.7 ± 2.4° (mean ± 95% CI) and the sensitivity (in degrees per second per g) showed a small but statistically significant increase with frequency. These characteristics contrast with those of cycloversion (conjugate torsion) during horizontal (interaural) inertial stimuli at similar frequencies. From these and previous results, we propose that cyclovergence during vertical translation has two sources, one, like cycloversion, from the low-frequency component of linear acceleration, and another, which we term dynamic cyclovergence, with high-pass characteristics. Furthermore, we suggest that this cyclovergence response in humans is a vestige of the response of lateral-eyed animals to vertical linear acceleration of the head.
当人体沿身体纵轴加速时，右眼和左眼表现出相反方向的扭转调制（旋聚）。这种矛盾反应的起源尚不清楚。我们研究了健康人体在直线正弦垂直运动过程中的旋聚。一个小的头部固定视觉目标最小化了眼睛的水平和垂直运动，从而隔离了扭转分量。对于 1 到 2 Hz 之间的刺激（接近头部运动的自然范围），相对于惯性加速度的旋聚相位为 8.7 ± 2.4°（平均值 ± 95%置信区间），并且灵敏度（以每秒每克度为单位）随着频率的增加呈现出微小但具有统计学意义的增加。这些特征与在类似频率的水平（耳间）惯性刺激期间的旋转变速（共轭扭转）的特征形成对比。根据这些和以前的结果，我们提出，在垂直平移过程中，旋聚有两个来源，一个类似于旋转变速，来自线性加速度的低频分量，另一个，我们称之为动态旋聚，具有高通特性。此外，我们认为这种人类的旋聚反应是侧眼动物对头部垂直线性加速度反应的残余。
