Cross-axis adaptation of torsional components in the yaw-axis vestibulo-ocular reflex.
Cross-axis adaptation of torsional components in the yaw-axis vestibulo-ocular reflex.
复制标题
偏航轴前庭眼反射中扭转分量的跨轴适应。
DOI：
10.1007/s00221-002-1285-4
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Zee,DS
中科院分区：
文献类型：
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作者：
Trillenberg,P;Shelhamer,M;Roberts,DC;Zee,DS
迷路内的三对半规管与六条眼外肌的牵拉方向并不完全一致。因此，对于给定的头部运动，前庭眼反射（VOR）取决于中枢神经机制，该中枢神经机制将神经管与具有适当功能增益的肌肉耦合，以便产生使眼睛围绕正确轴旋转正确量的响应。这些神经连接的结果是跨轴适应能力，当头部围绕一个轴旋转而视觉运动围绕另一个轴时，可以通过实验刺激这种能力。从这种视觉-前庭冲突中，大脑推断慢相眼球运动正在围绕错误的轴旋转。我们探讨了人类的跨轴适应能力，使用短期训练范例，以确定扭转眼球运动是否可以引起偏航（水平）头部旋转（扭转通常是不合适的）。我们应用偏航正弦头部旋转（±10°，0.33 Hz），并在黑暗中以及适应前后测量眼动反应。适应范式持续45-60 min，包括相同的头部运动，再加上移动的视觉场景，需要以下几种类型的眼球运动之一：（1）单独扭转（-Roll）;（2）水平/扭转，头向右/CW扭转（偏航-滚转）;（3）水平/扭转，头向右/逆时针扭转（偏航+滚转）;（4）水平、垂直、扭转组合（偏航+俯仰-滚转）;以及（5）水平和垂直一起（偏航+俯仰）。扭转振幅的最大和最显着变化发生在偏航-滚转和偏航+滚转条件下。我们的结论是，短期，跨轴适应扭转是可能的，但受适应任务的复杂性：如果需要一个以上的交叉耦合组件，产生较小的扭转组件。相比之下，垂直交叉轴分量可以很容易地训练与偏航头运动一起发生。
The three pairs of semicircular canals within the labyrinth are not perfectly aligned with the pulling directions of the six extraocular muscles. Therefore, for a given head movement, the vestibulo-ocular reflex (VOR) depends upon central neural mechanisms that couple the canals to the muscles with the appropriate functional gains in order to generate a response that rotates the eye the correct amount and around the correct axis. A consequence of these neural connections is a cross-axis adaptive capability, which can be stimulated experimentally when head rotation is around one axis and visual motion about another. From this visual-vestibular conflict the brain infers that the slow-phase eye movement is rotating around the wrong axis. We explored the capability of human cross-axis adaptation, using a short-term training paradigm, to determine if torsional eye movements could be elicited by yaw (horizontal) head rotation (where torsion is normally inappropriate). We applied yaw sinusoidal head rotation (±10°, 0.33 Hz) and measured eye movement responses in the dark, and before and after adaptation. The adaptation paradigm lasted 45–60 min, and consisted of the identical head motion, coupled with a moving visual scene that required one of several types of eye movements: (1) torsion alone (-Roll); (2) horizontal/torsional, head right/CW torsion (Yaw-Roll); (3) horizontal/torsional, head right/CCW torsion (Yaw+Roll); (4) horizontal, vertical, torsional combined (Yaw+Pitch-Roll); and (5) horizontal and vertical together (Yaw+Pitch). The largest and most significant changes in torsional amplitude occurred in the Yaw-Roll and Yaw+Roll conditions. We conclude that short-term, cross-axis adaptation of torsion is possible but constrained by the complexity of the adaptation task: smaller torsional components are produced if more than one cross-coupling component is required. In contrast, vertical cross-axis components can be easily trained to occur with yaw head movements.