PARTICIPATION OF THE CAUDAL FASTIGIAL NUCLEUS IN SMOOTH-PURSUIT EYE-MOVEMENTS .1. NEURONAL-ACTIVITY
PARTICIPATION OF THE CAUDAL FASTIGIAL NUCLEUS IN SMOOTH-PURSUIT EYE-MOVEMENTS .1. NEURONAL-ACTIVITY
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DOI：
10.1152/jn.1994.72.6.2714
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发表时间：
1994-12-01
影响因子：
2.5
通讯作者：
STRAUBE, A
中科院分区：
文献类型：
--
作者：
FUCHS, AF;ROBINSON, FR;STRAUBE, A
1.我们记录了两只恒河猴在用眼睛追踪运动小目标时，小脑输出核--顶核--神经元的单位活动。当小目标的正弦运动或阶跃运动引起平稳追逐眼球运动时，顶核尾侧部分的许多神经元表现出放电频率的调制。在单位射击中，对正弦目标运动的调制最强烈的追击方向可以是水平、垂直或倾斜。大多数情况下，偏爱的方向是对侧和/或向下方向(69个神经元中的50个)或同侧和/或向上方向(69个神经元中的13个)。在正弦追踪过程中，对侧/向下或同侧/向上优先选择平滑追踪方向的单位，以0.5-0.8赫兹周期调制的相移来衡量的峰值放电发生在峰值速度时间附近。80%的对侧/向下优先方向神经元的放电比眼速平均提前-27度；因此，这些神经元在眼球加速过程中放电最大。相反，同侧/向上优先方向的神经元峰值速度平均滞后+10.5度，因此在眼球减速时放电。在0.5~0.8赫兹范围内，正弦追踪的平均眼速敏感度为0.83+/-0.57(SD)棘波/S/度/S。我们还测试了36个单位在不同频率下对其偏好方向的放电频率，发现放电频率随最大眼速单调增加。然而，不同单位的射击速度在20至60度/S的速度范围内饱和。当一只猴子跟踪一个阶梯坡道目标的运动时，在测试的27个单元中出现了三种放电模式。刚刚超过一半的单位在眼球加速前(平均导联为27.4+/-17ms)发出尖峰脉冲，并持续到眼球加速的最初三分之一；紧随其后的是随后的稳定发射，在眼球加速到稳定速度后继续。较少的神经元释放出一次爆发，开始于加速后期，随后是稳定的放电。偶见神经元仅在加速过程中放电频率逐渐增加，然后稳定放电。在被测试的31个高空平滑追逐单元中，有30个单元在正弦偏航和/或俯仰振荡期间也被调制，同时动物盯着一个与它们一起旋转的点。与绒毛状浦肯野细胞不同，顶端平滑追踪神经元对眼球速度和头部速度的敏感度往往不同。大约一半的人对头部速度更敏感，另一半人对眼球速度的敏感性更高。我们的数据表明，尾状顶核可能在平稳追赶的初始加速和维持过程中起着重要作用。同一区域内存在与眼跳相关的神经元，其放电与对侧有关
1. We recorded single-unit activity from neurons of an output of the cerebellum, the fastigial nucleus, in two rhesus macaques while the monkeys tracked small moving targets with their eyes. Many neurons in the caudal part of the fastigial nucleus exhibited a modulation in their discharge rates when smooth-pursuit eye movements were elicited by either sinusoidal or step-ramp motions of a small target.2. The pursuit direction that elicited the most vigorous modulation in unit firing to sinusoidal target motion could be horizontal, vertical, or oblique. Most often, the preferred direction was in the contralateral and/or downward direction (50 of 69 neurons) or in the ipsilateral and/or upward direction (13 of 69).3. For units whose preferred smooth-pursuit directions were either contralateral/downward or ipsilateral/upward during sinusoidal pursuit, peak firing as measured by the phase shift of periodic modulation at 0.5-0.8 Hz occurred near the time of peak velocity. The discharge of 80% of the neurons with contralateral/downward preferred directions preceded eye velocity by an average of -27 degrees; thus these neurons discharged maximally during eye acceleration. In contrast, neurons with ipsilateral/upward preferred directions lagged peak velocity by an average of +10.5 degrees and therefore discharged during eye deceleration.4. The average eye velocity sensitivity for sinusoidal pursuit between 0.5 and 0.8 Hz was 0.83 +/- 0.57 (SD) spikes/s per degrees/s. We also tested 36 units during pursuit at a variety of frequencies in their preferred directions and found that firing rates increased monotonically with peak eye velocity. However, the firing rate saturated at velocities ranging from 20 to 60 degrees/s for different units.5. When a monkey tracked a step-ramp target motion, three discharge patterns emerged in the 27 units tested. Just over half of the units discharged a burst of spikes that preceded (average lead of 27.4 +/- 17 ms) and lasted throughout the initial third of the eye acceleration; the burst was followed by a subsequent steady firing that continued after the eye had accelerated to its steady velocity. Fewer neurons discharged a burst that began late in the acceleration and was followed by steady firing. Occasional neurons showed only a gradual increase in firing rate during acceleration followed by a steady discharge.6. Thirty of the 31 fastigial smooth-pursuit units tested also were modulated during sinusoidal yaw and/or pitch oscillations while the animals fixated a spot that rotated with them. Unlike floccular Purkinje cells, fastigial smooth-pursuit neurons often had unequal sensitivities to eye and head velocity. Approximately half had greater sensitivities to head velocity and half to eye velocity.7. Our data suggest that the caudal fastigial nucleus may play a prominent role both in the initial acceleration of smooth pursuit and possibly in its maintenance. The existence in this same area of saccade-related neurons whose discharge is related to contralateral