Three-dimensional organization of otolith-ocular reflexes in rhesus monkeys .1. Linear acceleration responses during off-vertical axis rotation
Three-dimensional organization of otolith-ocular reflexes in rhesus monkeys .1. Linear acceleration responses during off-vertical axis rotation
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DOI：
10.1152/jn.1996.75.6.2405
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发表时间：
1996-06-01
影响因子：
2.5
通讯作者：
Hess, BJM
中科院分区：
文献类型：
--
作者：
Angelaki, DE;Hess, BJM
1. 研究了沿三个基本头轴正弦线性加速度引起的恒河猴耳石-眼反射在离垂直轴旋转过程中的动态特性。当头部在空间中沿非垂直轴匀速旋转时，耳石-眼反射会对沿耳间轴、鼻枕轴或垂直头轴的正弦变化的线性加速度（重力）分量产生反应。由于这些正弦刺激的频率与旋转的速度成正比，低速和中速旋转可以研究耳石-眼反射的中低频动态。动物们在完全黑暗的环境中以7.4到184度/秒的速度在偏航、俯仰和滚转平面上旋转。因此，在0.02 - 0.51 Hz的刺激频率范围内，耳石-眼反射（表现为眼睛位置和/或慢相眼速的正弦调制）被定量研究。在偏航和滚转期间，扭转、垂直和水平慢相眼速度作为头部位置的函数进行正弦调制。这些响应的振幅对相反方向的旋转是对称的。相反，在俯仰旋转过程中，主要是垂直慢相眼速度被调制。这种调制对于相反方向的旋转是不对称的。在给定的旋转平面中，每一个响应分量都可以与耳石-眼响应向量相关联，耳石-眼响应向量的灵敏度、时间相位和空间方向是根据两个旋转方向中正弦调制的振幅和相位来估计的。基于这一分析，对单独的慢相眼速度或全眼偏移（包括慢速和快速眼运动）进行了分析，观察到两种不同的反应模式：1)响应向量具有明显的动态和时空特性，可以表征为“平移”耳石-眼反射的低频范围；2)与眼睛位置与头部位置相一致的调制（“倾斜”耳石眼屈曲）相关的响应向量。与两个耳石-眼矢量相关的明显动态反应包括沿耳间轴的重力函数引起的水平眼运动和沿垂直头部轴的重力函数引起的垂直眼运动。这两种反应的特点是慢相眼速度敏感性增加了三到五倍，在0.02和0.51 Hz之间的大相位变化类似于100-180度。这些动态特性可能提示在眼孔和眼孔通路中进行非传统的时间加工，可能涉及时空耳石-眼相互作用。与眼位反应相对应的两个耳石-眼矢量（倾斜耳石-眼反射）包括沿耳间轴响应重力的扭转眼运动和沿鼻枕头轴响应重力的垂直眼运动。这些耳石-眼反应并不仅仅是由于耳石对慢眼运动的影响。特别是在高频率（即高速旋转）下，扫视负责扭转和垂直眼睛位置的大部分调制，这是相对较大的（平均+/- 8-10度/g），并且保持独立于频率。这种反射动力学可以通过直接耦合初级耳石传入输入来模拟动眼植物。尽管由于快速和缓慢的眼球运动，扭转和垂直的眼球位置都有很大的调制，但慢相眼速度的调制在所有频率下都很小（平均为+/- 4-10度/秒/克）。这些结果表明，扭转和垂直反应（以前被描述为“反滚动”和“反俯仰”或倾斜耳石-眼反射）代表了灵长类动物眼球运动系统中快速和慢速眼球运动成分的耳石效应。耳石对快速和慢速眼球运动的综合影响可能反映了动眼肌（即Listing’s）坐标对头部空间方向的动态依赖，表明这种功能可能与空间方向和运动协调有关，而不是与凝视稳定有关。
1. The dynamic properties of otolith-ocular reflexes elicited by sinusoidal linear acceleration along the three cardinal head axes were studied during off-vertical axis rotations in rhesus monkeys. As the head rotates in space at constant velocity about an off-vertical axis, otolith-ocular reflexes are elicited in response to the sinusoidally varying linear acceleration (gravity) components along the interaural, nasooccipital, or vertical head axis. Because the frequency of these sinusoidal stimuli is proportional to the velocity of rotation, rotation at low and moderately fast speeds allows the study of the mid- and low-frequency dynamics of these otolith-ocular reflexes.2. Animals were rotated in complete darkness in the yaw, pitch, and roll planes at velocities ranging between 7.4 and 184 degrees/s. Accordingly, otolith-ocular reflexes (manifested as sinusoidal modulations in eye position and/or slow-phase eye velocity) were quantitatively studied for stimulus frequencies ranging between 0.02 and 0.51 Hz. During yaw and roll rotation, torsional, vertical, and horizontal slow-phase eye velocity was sinusoidally modulated as a function of head position. The amplitudes of these responses were symmetric for rotations in opposite directions. In contrast, mainly vertical slow-phase eye velocity was modulated during pitch rotation. This modulation was asymmetric for rotations in opposite direction.3. Each of these response components in a given rotation plane could be associated with an otolith-ocular response vector whose sensitivity, temporal phase, and spatial orientation were estimated on the basis of the amplitude and phase of sinusoidal modulations during both directions of rotation. Based on this analysis, which was performed either for slow-phase eye velocity alone or for total eye excursion (including both slow and fast eye movements), two distinct response patterns were observed: 1) response vectors with pronounced dynamics and spatial/temporal properties that could be characterized as the low-frequency range of ''translational'' otolith-ocular reflexes; and 2) response vectors associated with an eye position modulation in phase with head position (''tilt'' otolithocular flexes).4. The responses associated with two otolith-ocular vectors with pronounced dynamics consisted of horizontal eye movements evoked as a function of gravity along the interaural axis and vertical eye movements elicited as a function of gravity along the vertical head axis. Both responses were characterized by a slow-phase eye velocity sensitivity that increased three- to five-fold and large phase changes of similar to 100-180 degrees between 0.02 and 0.51 Hz. These dynamic properties could suggest nontraditional temporal processing in utriculoocular and sacculoocular pathways, possibly involving spatiotemporal otolith-ocular interactions.5. The two otolith-ocular vectors associated with eye position responses in phase with head position (tilt otolith-ocular reflexes) consisted of torsional eye movements in response to gravity along the interaural axis, and vertical eye movements in response to gravity along the nasooccipital head axis. These otolith-ocular responses did not result from an otolithic effect on slow eye movements alone. Particularly at high frequencies (i.e., high speed rotations), saccades were responsible for most of the modulation of torsional and vertical eye position, which was relatively large (on average +/- 8-10 degrees/g) and remained independent of frequency. Such reflex dynamics can be simulated by a direct coupling Of primary otolith afferent inputs to the oculomotor plant. Despite the large modulation of torsional and vertical eye position due to both fast and slow eye movements, modulation of slow-phase eye velocity was small for all frequencies (on average +/- 4-10 degrees/s/g).6. These results suggest that torsional and vertical responses (previously described as ''counter-rolling'' and ''counter-pitching'' or tilt otolith-ocular reflexes) represent an otolithic effect on both fast and slow eye movement components of the primate oculomotor system. The combined otolithic effect on both fast and slow eye movements possibly reflects a dynamic dependence of oculomotor (i.e., Listing's) coordinates on head orientation in space, suggesting a function that is probably related to spatial orientation and motor coordination rather than gaze stabilization.