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Role of inhibition in adaptation of vestibular and saccadic eye movements.

抑制在前庭和眼跳眼球运动适应中的作用。

基本信息

批准号：
16300129
负责人：
YOSHIDA Kaoru
金额：
$ 7.49万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

The accuracy of vestibular and saccadic eye movements is maintained by motor learning mechanisms. We examined 1) a role of inhibition in the premotor pathways participating in these eye movements, and 2) the pathways mediating error signals for saccadic adaptation.Using a multibarel microelectrode, we recorded single unit activity from cells in the vestibular nucleus and pontine reticular formation, and iontophoretically applied GABA receptor antagonists or glycine receptor antagonist. Following application of GABA antagonists, horizontal canal-related secondary vestibular neurons showed a marked increase in the gain of their response to head rotation. Analysis of the response phase suggested that these neurons received GABAergic input of non-commissural origin, most likely from the flocculus. On the other hand, glycinergic inhibition played critical roles in generation of saccadic command. Thus, both the inhibitory trigger and latch signals to omnipause neurons were mediated by glycin … More ergic afferents. Inhibition from omnipause neurons to premotor burst neurons was also glycinergic and found to be necessary to suppress visual responses.We examined effects of repetition of saccadic adaptation during single experiments. Analyses revealed that a memory of previous learning remains during recovery and facilitates subsequent adaptation. This memory does not disappear merely with time but is erased actively by repeated zero-error movements. Results suggest that the saccadic system is equipped with more than one plasticity process.Error signals are vital to motor learning. However, little is known about pathways that transmit error signals for saccadic adaptation. We found that microstimulation of the midbrain tegmentum following saccades produces gradual and marked changes in saccade gain. The spatial and temporal characteristics of the produced changes were similar to those of adaptation induced by real visual error. We conclude that microstimulation created powerful learning signals that dictate the direction of adaptive shift in saccade endpoints. Less

前庭和扫视眼球运动的准确性由运动学习机制维持。我们研究了1）抑制在参与这些眼球运动的前运动通路中的作用，以及2）调节扫视适应错误信号的通路，使用multibarel微电极，我们记录了前庭核和脑桥网状结构中细胞的单个单位活动，以及离子电渗应用GABA受体拮抗剂或甘氨酸受体拮抗剂。应用GABA拮抗剂后，水平管相关的次级前庭神经元显示出显着增加，其响应头部旋转的增益。反应时相的分析表明，这些神经元接收GABA能输入的非连合起源，最有可能从绒球。另一方面，甘氨酸能抑制在扫视命令的产生中起关键作用。因此，对全间歇神经元的抑制性触发和闭锁信号都是由甘氨酸介导的 ...更多信息能传入神经从omnipause神经元到前运动爆发神经元的抑制也是甘氨酸能的，并且被发现是抑制视觉responses.We研究了在单个实验中重复扫视适应的影响。分析表明，在恢复过程中，以前的学习记忆仍然存在，并促进随后的适应。这种记忆不会仅仅随着时间的推移而消失，而是通过重复的零错误运动而被主动擦除。结果表明，扫视系统具有多个可塑性过程，错误信号对运动学习至关重要。然而，很少有人知道的途径，传输错误信号的扫视适应。我们发现，微刺激中脑被盖后扫视产生渐进的和显着的变化扫视增益。产生的变化的空间和时间特征与真实的视觉误差引起的适应相似。我们的结论是，微刺激产生了强大的学习信号，决定了眼跳端点的适应性转变的方向。少