ROLE OF CEREBELLAR PARALLEL FIBERS IN SACCADE ACCURACY

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 这项研究的目的是了解小脑如何将传入的眼动信号转换为它发送给眼动系统的信号。我们认为，眼跳的准确性取决于在正确的时间停止眼跳的信号。最初，我们认为这种信号在轴突中穿过小脑中线，称为平行纤维(p纤维)。在过去的一年里，我们通过切断这些纤维来测试这一提议，同时将对伤口周围组织的损害降至最低。我们发现，切断穿过中线的P-纤维并不会扰乱眼跳减速。 我们现在认为，眼跳减速的不足是由于切口周围的组织损伤所致。目前，我们正准备通过沿着小脑皮质中线进行狭窄的矢状面损伤来检验这一假说。 在一个相关的实验中，我们将使用解剖学追踪来描述小脑皮质外侧和内侧部分的连接，以确定小脑的不同部分如何连接到小脑核。初步数据显示，小脑扫视部分的外侧和内侧区域有不同的联系。描述这一点将告诉我们小脑如何做出不同大小的运动。 除了展示小脑如何产生使眼球运动准确的信号外，这项工作还将展示为什么眼跳以及随后的视力会因损害小脑的手术而严重受损。这种手术很常见，因为儿童中最常见的脑瘤位于小脑下方。因此，我们的工作将激励和指导易于实施的治疗和手术修改，以在不损害视力的情况下移除肿瘤。这样的改进可以迅速帮助患者，因为他们不需要其他创新。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of this research is to understand how the cerebellum transforms incoming eye movement signals into the signals that it sends to the oculomotor system. We propose that saccade accuracy depends on a signal that stops saccades at the right time. Initially we thought that this signal traveled across the midline of the cerebellum in the axons called parallel fibers (p-fibers). In the past year we have tested this proposal by cutting these fibers while minimizing damage to the tissue around the cut. We found that cutting p-fibers that cross the midline does not disrupt saccade deceleration. We now believe that a deficit in saccade deceleration resulted from tissue damage around the incision. Currently we are preparing to test this hypothesis by making narrow sagittal lesions along the midline of the cerebellar cortex. In a related experiment we will use anatomical tracing to describe the connections from lateral and medial parts of the cerebellar cortex to determine how different parts of the cerebellum connect to the cerebellar nuclei. Preliminary data show that the lateral and medial areas of the saccade part of the cerebellum make different connections. Describing this will tell us how the cerebellum makes movements of different sizes. In addition to showing how the cerebellum produces signals that make eye movements accurate this work will also show why saccades, and consequently vision, are badly impaired by surgery that damages the cerebellum. This surgery is common because the most common brain tumors in children are immediately under the cerebellum. Thus, our work will motivate and guide easy-to-implement modifications of treatment and surgery to removes tumors without impairing vision. Such improvements could help patients quickly because they require no other innovations.