Department of Physiology and Biophysics, Washington National Primate Research Center, University of Washington, Seattle, Washington, Washington, 98195-7330, USA.
Sci Rep. 2017 Aug 29;7(1):9566. doi: 10.1038/s41598-017-10242-z.
Saccadic eye movements provide a valuable model to study the brain mechanisms underlying motor learning. If a target is displaced surreptitiously while a saccade is underway, the saccade appears to be in error. If the error persists gradual neuronal adjustments cause the eye movement again to land near the target. This saccade adaptation typically follows an exponential time course, i.e., adaptation speed slows as adaptation progresses, indicating that the sensitivity to error decreases during adaptation. Previous studies suggested that the superior colliculus (SC) sends error signals to drive saccade adaptation. The objective of this study is to test whether the SC error signal is related to the decrease in the error sensitivity during adaptation. We show here that the visual activity of SC neurons, which is induced by a constant visual error that drives adaptation, decreases during saccade adaptation. This decrease of sensitivity to visual error was not correlated with the changes of primary saccade amplitude. Therefore, a possible interpretation of this result is that the reduction of visual sensitivity of SC neurons contributes an error sensitivity signal that could help control the saccade adaptation process.
扫视眼动为研究运动学习的大脑机制提供了一个有价值的模型。如果在进行扫视时目标被偷偷移动，那么扫视看起来就会出错。如果这种错误持续存在，逐渐的神经元调整会导致眼球运动再次靠近目标。这种扫视适应通常遵循指数时间过程，即适应速度随着适应的进行而减慢，这表明在适应过程中对错误的敏感性降低。先前的研究表明，上丘 (SC) 会发送错误信号来驱动扫视适应。本研究的目的是检验 SC 错误信号是否与适应过程中错误敏感性的降低有关。我们在这里表明，由驱动适应的恒定视觉误差引起的 SC 神经元的视觉活动在扫视适应过程中会减少。这种对视觉错误的敏感性降低与主要扫视幅度的变化无关。因此，对这一结果的一种可能解释是，SC 神经元的视觉敏感性降低提供了一个错误敏感性信号，有助于控制扫视适应过程。
