Temporal Synthesis of Vestibular and Extra-Vestibular Sensory Signals

多种感觉线索是由离散的事件产生的，虽然它们没有到达大脑， 同时，如果它们被解释为对应于单个事件，大脑可以合成它们。这 是至关重要的，因为如果两个或多个相关的线索， 如果不相关的输入被错误地合成，则相反地被降级。研究很少 专注于前庭和非前庭线索的时间绑定， 在一个固有的多模态环境中，实际上对时间约束的异常一无所知 发生于外周或中枢前庭障碍。时间绑定通常用两个值来量化 从心理物理测试中得出，主观一致性点（PSS）和时间绑定窗口 （TBW）。我们将使用这些感知测量来测试一系列关于生理学的假设， 前庭颞部束缚的病理生理学将研究两组具体目标：目标1将 研究大脑用于及时结合前庭和非前庭信号的机制。目标1A 研究前庭信号的精确性如何影响其与非前庭线索的结合。精度 前庭传入神经的空间和时间特征及其与时间的关系 结合将在正常受试者中进行研究，我们预测这两个精度测量将是相关的 与对方和TBW。我们还将使用患者的前庭精度， 前庭（VI）和耳蜗（CI）植入在同一只耳朵，并预测额外的噪音将扩大TBW 提高PSS。目的1B使用VI-CI患者中可用的假体信号来检查 习惯性暴露于时间线索驱动的适应如何影响时间约束。因为大脑是天真的， 这些刺激对和患者在这两种情况下都长期缺乏耳蜗和前庭功能， 耳朵，我们可以研究大脑如何在没有事先接触到线索的情况下及时结合信号，并预测 PSS将反映信号到达大脑的相对时间，TBW将很宽， 会异常地适应环境目的2研究时间绑定如何有助于 外周和中枢前庭疾病的病理生理学。目的2A检查急性丧失 外周前庭功能和随后的时间约束补偿过程。我们预测 被动和主动过程都将有助于PSS和TBW的重新校准， 结果将与这些值的变化相关，并且PSS和TBW的适应性将得到改善 临床结果。目的2B检查时间约束如何导致中枢前庭功能障碍， 专注于晕车和偏头痛我们预测患有更严重晕动病的受试者将 具有更宽的TBW，并且缩小TBW的适应将降低对运动病的易感性。

Multiple sensory cues are generated by discrete events and while they do not reach the cerebrum simultaneously, the brain can synthesize them if they are interpreted as corresponding to a single event. This is critical because the central representation of an event or action is improved if two or more relevant cues are integrated but conversely is degraded if unrelated inputs are mistakenly synthesized. Little research has focused on temporal binding of vestibular and non-vestibular cues even though the vestibular system operates in an inherently multimodal environment, and virtually nothing is known about abnormalities in temporal binding that occur with peripheral or central vestibular disorders. Temporal binding is often quantified with two values derived from psychophysical tests, the point of subjective simultaneity (PSS) and the temporal binding window (TBW). We will use these perceptual measures to test a series of hypotheses about the physiology and pathophysiology of vestibular temporal binding. Two sets of specific aims will be investigated: Aim 1 will investigate the mechanisms used by the brain to bind vestibular and non-vestibular signals in time. Aim 1A examines how the precision of the vestibular signal affects its binding with non-vestibular cues. Precision (1/variability) of the spatial and temporal characteristics of vestibular afferents and their relationship to temporal binding will be studied in normal subjects, and we predict that the two precision measures will be correlated with each other and with the TBW. We will also manipulate vestibular precision using patients with combined vestibular (VI) and cochlear (CI) implants in the same ear and predict that additional noise will widen the TBW and increase the PSS. Aim 1B uses the prosthetic signals that are available in the VI-CI patients to examine how adaptation driven by habitual exposure to timing cues affects temporal binding. Since the brain is naïve to these stimulus pairs and the patients have longstanding absence of cochlear and vestibular function in both ears, we can study how the brain binds signals in time when it has no prior exposure to the cues, and predict that the PSS will reflect the relative time for the signals to reach the cerebrum, the TBW will be wide, and both will be abnormally amenable to adaptation. Aim 2 investigates how temporal binding contributes to the pathophysiology of peripheral and central vestibular disorders. Aim 2A examines the effects of acute loss of peripheral vestibular function and the subsequent process of compensation on temporal binding. We predict that both passive and active processes will contribute to recalibration of the PSS and TBW, that patient outcome will correlate with the changes in these values, and that adaptation of the PSS and TBW will improve clinical outcome. Aim 2B examines how temporal binding contributes to central vestibular dysfunction, focusing on motion sickness and migraine. We predict that subjects with more severe motion sickness will have wider TBWs and that adaptation that narrows the TBW will reduce susceptibility to motion sickness.