Plasticity of the Human Oculomotor Integrator through Real-Time Visual Feedback

通过实时视觉反馈实现人类动眼神经积分器的可塑性

• 批准号: 7017281
• 负责人: Hyunjune SEBASTIAN SEUNG
• 金额: $ 8.24万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2006-05-02
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7017281
• 关键词: Plasticity; Human; Oculomotor; Integrator; through

DESCRIPTION (provided by applicant): The vertebrate oculomotor integrator is responsible for stabilizing gaze at all eye positions by driving the extraocular motor nuclei with a steady rate of neural activity proportional to eye position. Disorders of this system can manifest as nystagmus. The integrator performs stability by maintaining a precisely tuned level of neural feedback. This level of feedback can be experimentally manipulated- the integrator has been shown to exhibit short-term plasticity in response to visual-vestibular conflict in humans. In the goldfish, a leaky or unstable neural integrator can be induced using visual feedback alone, by adjusting the velocity of an optokinetic stimulus in real-time as a function of horizontal eye position. The principal aim of the present study is to extend this methodology to humans. The preliminary data herein support the hypothesis that human oculomotor dynamics are manipulated by purely visual feedback. By measuring eye position with infrared eye-tracking technology and controlling the horizontal velocity of a computer-driven optokinetic stimulus, we have been able to elicit leakiness and instability in a small sample of normal human subjects. The current proposal aims to extend these findings and to broadly characterize this phenomenon in humans. The first set of experiments will compare several different optokinetic training paradigms for efficacy in producing the observed plasticity. In doing so, the time course of the effect and of recovery will be elucidated. Subsequent experiments will assess the repeatability of the effect and determine the dependence of recovery on stable visual feedback. Finally, we will make finer adjustments to the real-time visual feedback parameters in an attempt to mold integrator dynamics in a more detailed fashion than simply inducing leak or instability. The purpose of this line of research is 2-fold. Clinically, it is hoped that the principles revealed in this study can be adapted to alter neural integrator performance in patients with nystagmus. The gaze-evoked and pendular subtypes of nystagmus may be most tractable initially, since these forms have the most reliable relationship between eye position and drift velocity. Mechanistically, the human-relevance of goldfish integrator research has been recently supported by comparing high-resolution eye-movement measurements in the 2 species. These measurements reveal a high degree of quantitative similarity between their oculomotor systems, which is surprising in light of the vast differences between their visual systems. Repeating the goldfish plasticity experiments in humans will help in assessing the general relevance of ongoing vertebrate research aimed at revealing the cellular and network mechanisms of neural integration.

描述（由申请人提供）：脊椎动物动眼神经积分器负责通过以与眼睛位置成比例的稳定的神经活动速率驱动眼外运动核来稳定所有眼睛位置的注视。该系统的疾病可表现为眼球震颤。积分器通过维持精确调节的神经反馈水平来实现稳定性。这种反馈水平可以通过实验来操纵——积分器已被证明在响应人类视觉前庭冲突时表现出短期可塑性。在金鱼中，仅使用视觉反馈就可以通过根据水平眼睛位置实时调整视动刺激的速度来诱导泄漏或不稳定的神经积分器。本研究的主要目的是将这种方法扩展到人类。本文的初步数据支持这样的假设：人类动眼神经动力学是由纯粹的视觉反馈操纵的。通过使用红外眼动追踪技术测量眼睛位置并控制计算机驱动的视动刺激的水平速度，我们已经能够在正常人类受试者的小样本中引出泄漏和不稳定性。目前的提案旨在扩展这些发现并广泛描述人类中的这种现象。第一组实验将比较几种不同的光动训练范例，以了解产生观察到的可塑性的功效。在此过程中，将阐明效果和恢复的时间过程。随后的实验将评估效果的可重复性，并确定恢复对稳定视觉反馈的依赖性。最后，我们将对实时视觉反馈参数进行更精细的调整，以尝试以更详细的方式塑造积分器动态，而不是简单地引起泄漏或不稳定。这一系列研究的目的有两个。在临床上，希望本研究揭示的原理能够适用于改变眼球震颤患者的神经积分器性能。眼球震颤的凝视诱发亚型和摆动亚型最初可能最容易处理，因为这些形式在眼睛位置和漂移速度之间具有最可靠的关系。从机制上讲，金鱼积分器研究与人类的相关性最近通过比较这两个物种的高分辨率眼动测量结果得到了支持。这些测量结果揭示了他们的动眼系统之间高度的数量相似性，鉴于他们的视觉系统之间的巨大差异，这是令人惊讶的。在人类身上重复金鱼可塑性实验将有助于评估正在进行的脊椎动物研究的总体相关性，该研究旨在揭示神经整合的细胞和网络机制。