Reversible inactivation of monkey superior colliculus. I. Curvature of saccadic trajectory
Reversible inactivation of monkey superior colliculus. I. Curvature of saccadic trajectory
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DOI：
10.1152/jn.1998.79.4.2082
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发表时间：
1998-04-01
影响因子：
2.5
通讯作者：
Wurtz, RH
中科院分区：
文献类型：
--
作者：
Aizawa, H;Wurtz, RH
猴上级丘（SC）中间层中在扫视运动前放电的神经元至少可分为爆发型和积累型两种类型，它们的特征差异与这两种细胞类型的不同功能贡献是一致的。已经提出，在扫视产生期间，活动在积聚神经元群体中的传播可能有助于控制扫视眼球运动。任何这样的传播的影响应该是在水平和垂直分量的扫视，因为SC上的运动场的地图是一个二维的，它应该影响的轨迹扫视。本实验使用蝇蕈醇注射到SC内的视皮层区域，以确定这种活动扩散对扫视轨迹的功能贡献。分析集中在对视野区域的扫视上，这些区域应该主要受到积聚神经元活动改变的影响。蝇蕈醇注射产生的眼跳改变轨迹，他们成为一致的注射后弯曲，连续眼跳相同的目标有类似的曲率。弯曲的扫视在扫视的最开始显示出它们的方向和速度的变化，并且对于那些到达目标的扫视，扫视的方向在接近结束时被改变以补偿最初不正确的方向。注射后扫视有较低的峰值速度，较长的持续时间，和较长的启动时间。蝇蕈醇注射引起的扫视轨迹的变化，沿着先前对这种注射的扫视速度变化的观察，表明SC参与影响扫视期间以及扫视结束时的眼睛位置。当注射在SC中比最活跃的爆发神经元更靠近嘴侧时，轨迹的变化也与积聚神经元对眼轨迹控制的贡献一致。然而，这些结果并不支持SC中的积聚神经元充当空间积分器的假设。
The neurons in the intermediate layers of the monkey superior colliculus (SC) that discharge before saccadic eye movements can be divided into at least two types, burst and buildup neurons, and the differences in their characteristics are compatible with different functional contributions of the two cell types. It has been suggested that a spread of activity across the population of the buildup neurons during saccade generation may contribute to the control of saccadic eye movements. The influence of any such spread should be on both the horizontal and vertical components of the saccade because the map of the movement fields on the SC is a two-dimensional one; it should affect the trajectory of saccade. The present experiments used muscimol injections to inactivate areas within the SC to determine the functional contribution of such a spread of activity on the trajectory of the saccades. The analysis concentrated on saccades made to areas of the visual field that should be affected primarily by alteration of buildup neuron activity. Muscimol injections produced saccades with altered trajectories; they became consistently curved after the injection, and successive saccades to the same targets had similar curvatures. The curved saccades showed changes in their direction and speed at the very beginning of the saccade, and for those saccades that reached the target, the direction of the saccade was altered near the end to compensate for the initially incorrect direction. Postinjection saccades had lower peak speeds, longer durations, and longer latencies for initiation. The changes in saccadic trajectories resulting from muscimol injections, along with the previous observations on changes in speed of saccades with such injections, indicate that the SC is involved in influencing the eye position during the saccade as well as at the end of the saccade. The changes in trajectory when injections were made more rostral in the SC than the most active burst neurons also are consistent with a contribution of the buildup neurons to the control of the eye trajectory. The results do not, however, support the hypothesis that the buildup neurons in the SC act as a spatial integrator.