Rambold H, Sprenger A, Helmchen C
Department of Neurology, Medical University of Luebeck, D-23538 Luebeck, Germany.
J Neurophysiol. 2002 Sep;88(3):1220-33. doi: 10.1152/jn.2002.88.3.1220.
Blinks are known to change the kinematic properties of horizontal saccades, probably by influencing the saccadic premotor circuit. The neuronal basis of this effect could be explained by changes in the activity of omnipause neurons in the nucleus raphe interpositus or in the saccade-related burst neurons of the superior colliculus. Omnipause neurons cease discharge during both saccades and vergence movements. Because eyelid blinks can influence both sets of neurons, we hypothesized that blinks would influence the kinematic parameters of saccades in all directions, vergence, and saccade-vergence interactions. To test this hypothesis, we investigated binocular eye and lid movements in five normal healthy subjects with the magnetic search coil technique. The subjects performed conjugate horizontal and vertical saccades from gaze straight ahead to targets at 20 degrees up, down, right, or left while either attempting not to blink or voluntarily blinking. While following the same blink instruction, subjects made horizontal vergence eye movements of 7 degrees and combined saccade-vergence movements with a version amplitude of 20 degrees. The movements were performed back and forth from two targets simultaneously presented nearby (38 cm) and more distant (145 cm). Small vertical saccades accompanied most vergence movements. These results show that blinks change the kinematics (saccade duration, peak velocity, peak acceleration, peak deceleration) of not only horizontal but also of vertical saccades, of horizontal vergence eye movements, and of combined saccade-vergence eye movements. Peak velocity, acceleration, and deceleration of eye movements were decreased on the average by 30%, and their duration increased by 43% on the average when they were accompanied by blinks. The blink effect was time dependent with respect to saccade and vergence onset: the greatest effect occurred 100 ms prior to saccade onset, whereas there was no effect when the blink started after saccade onset. The effects of blinks on saccades and vergence, which are tightly coupled to latency, support the hypothesis that blinks cause profound spatiotemporal perturbations of the eye movements by interfering with the normal saccade/vergence premotor circuits. However, the measured effect may to a certain degree but not exclusively be explained by mechanical interference.
众所周知，眨眼可能通过影响扫视运动前运动回路来改变水平扫视的运动学特性。这种效应的神经学基础可以通过中间缝际核中的全暂停神经元或上丘中与扫视相关的爆发神经元活动的变化来解释。全暂停神经元在扫视和辐辏运动期间都会停止放电。由于眼睑眨眼会影响这两组神经元，我们推测眨眼会影响各个方向的扫视、辐辏以及扫视 - 辐辏相互作用的运动学参数。为了验证这一假设，我们使用磁搜索线圈技术研究了五名正常健康受试者的双眼和眼睑运动。受试者从直视前方进行共轭水平和垂直扫视，看向向上、向下、向右或向左20度的目标，同时要么试图不眨眼，要么自愿眨眼。在遵循相同的眨眼指令时，受试者进行了7度的水平辐辏眼球运动以及具有20度转动幅度的联合扫视 - 辐辏运动。这些运动在同时呈现于近处（38厘米）和远处（145厘米）的两个目标之间来回进行。大多数辐辏运动都伴有小的垂直扫视。这些结果表明，眨眼不仅会改变水平扫视的运动学（扫视持续时间、峰值速度、峰值加速度、峰值减速度），还会改变垂直扫视、水平辐辏眼球运动以及联合扫视 - 辐辏眼球运动的运动学。当眼球运动伴有眨眼时，其峰值速度、加速度和减速度平均降低30%，持续时间平均增加43%。眨眼效应在扫视和辐辏开始时间方面具有时间依赖性：最大效应出现在扫视开始前100毫秒，而当眨眼在扫视开始后开始时则没有效应。眨眼对扫视和辐辏的影响与潜伏期紧密相关，这支持了眨眼通过干扰正常的扫视/辐辏运动前运动回路导致眼球运动产生深刻时空扰动的假设。然而，所测得的效应在一定程度上但并非完全可以由机械干扰来解释。
