Temporal Synthesis of Vestibular and Extra-Vestibular Sensory Signals

多个感觉线索是由离散事件产生的，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，因为如果有两个或更多相关提示，则事件或动作的中心表示会得到改进 如果不相关的输入被错误地合成，则集成但相反地被降级。几乎没有研究表明 专注于前庭和非前庭线索的时间绑定，即使前庭系统运行 在固有的多模式环境中，对时间绑定中的异常几乎一无所知 出现外周或中枢性前庭紊乱。时态绑定通常用两个值来量化 来自心理物理测试、主观同时性(PSS)和时间约束窗口 (待定)。我们将使用这些感知测量来测试一系列关于生理学和 前庭暂时性捆绑的病理生理学。将调查两组具体目标：目标1将 研究大脑用来及时绑定前庭和非前庭信号的机制。目标1 A 研究前庭信号的精确度如何影响其与非前庭线索的结合。精密度 (1/变异性)前庭传入的时空特征及其与时间的关系 结合将在正常受试者中进行研究，我们预测这两个精确度测量将是相关的 彼此之间，以及与TBW之间。我们还将使用联合使用的患者来操作前庭精确度 前庭(VI)和人工耳蜗(CI)植入同一只耳朵，并预测额外的噪音将扩大TBW 增加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所驱动的适应如何影响时间捆绑。因为大脑太天真了 这些刺激对和患者都有长期的耳蜗和前庭功能缺失 耳朵，我们可以研究当大脑没有事先接触到信号时，它是如何及时绑定信号的，并预测 PSS将反映信号到达大脑的相对时间，TBW将是宽的，并且两者 将异常地服从于适应。目标2调查时间绑定如何对 外周和中枢性前庭疾病的病理生理学。目标2a研究了急性损失的影响 外周前庭功能及随后的代偿过程对时间捆绑的影响。我们预测 被动和主动过程都将有助于PSS和TBW的重新校准，该患者 结果将与这些值的变化相关，PSS和TBW的适应性将得到改善 临床结果。目的2B研究时间约束如何导致中央前庭功能障碍， 专注于晕动病和偏头痛。我们预测有更严重晕动病的受试者 拥有更宽的体型，而使体型变窄的适应能力将降低晕动病的易感性。

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.