Inaba Naoko, Iwamoto Yoshiki, Yoshida Kaoru
Department of Physiology, Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki 305-8575, Tsukuba, Japan.
Neurosci Res. 2003 Jul;46(3):359-68. doi: 10.1016/s0168-0102(03)00098-1.
The accuracy of saccades is ensured by an adaptive mechanism that probably involves the cerebellum. We examined the discharge of saccade-related neurons in the fastigial oculomotor region (FOR) during adaptation. Using a conventional intrasaccadic step paradigm, we changed the gain of saccades elicited by a 10 degrees horizontal target step to the side of unit recording. As a measure of neural activity, we took the number of spikes occurring in a 30 or 40 ms time window starting at 30 ms before saccade onset, which corresponded roughly to the foot and rising phase of the burst. A gain decrease was accompanied by a significant increase in spike discharge (6/6), and a gain increase by a significant reduction in discharge (3/3). During the course of adaptation, the neural activity and gain exhibited changes with a similar course but in the opposite direction. Regression analysis indicated that the two variables were significantly correlated (7/8). The present study has shown that activity of FOR neurons is altered during adaptive modification of saccade size. Our data are consistent with the hypothesized suppressive action of the FOR on ipsiversive saccades and provide support on a single-neuron basis for the cerebellar involvement in short-term saccade adaptation.
扫视的准确性由一种可能涉及小脑的适应性机制来确保。我们在适应性过程中检查了顶核动眼区（FOR）中与扫视相关的神经元的放电情况。使用传统的扫视内阶跃范式，我们将由向单位记录侧的10度水平目标阶跃诱发的扫视增益进行了改变。作为神经活动的一种度量，我们统计了从扫视开始前30毫秒开始的30或40毫秒时间窗口内出现的尖峰数量，这大致对应于爆发的足部和上升阶段。增益降低伴随着尖峰放电的显著增加（6/6），增益增加则伴随着放电的显著减少（3/3）。在适应性过程中，神经活动和增益呈现出相似但相反方向的变化。回归分析表明这两个变量显著相关（7/8）。本研究表明，在扫视大小的适应性改变过程中，FOR神经元的活动会发生改变。我们的数据与关于FOR对同侧性扫视的假设性抑制作用一致，并在单神经元基础上为小脑参与短期扫视适应性提供了支持。
