Vestibular influences on spatial orientation

描述(申请人提供)：这个项目的长期目标是了解大脑如何使用来自前庭迷宫的信息来估计头部的空间方向和运动。具体地说，这些实验将研究来自半规管的旋转线索和耳石器官传递的重力惯性线索之间的在线相互作用。将在恒河猴身上测量翻滚、倾斜、心理物理和眼球运动，而旋转线索则通过电刺激后管壶腹部神经来敏锐地操纵。管道线索将被孤立地呈现(头部处于不同的静态方向，眼睛处于不同的会聚角度)，并且还将与视觉(视动)和惯性线索相结合。倾斜知觉将通过来自主观视觉垂直(SVV)的心理物理任务来测量，SVV是一种被广泛用于评估前庭症状的测试。我们假设：1)由半规管提供的旋转线索有助于大脑对头部方向的估计，证据是在管道激活过程中SVV反应的变化，这不能用扭转眼睛位置的变化来解释；以及2)通过分离实际和估计的重力相对于头部的方向，电激活垂直管道将诱导对线加速度的异常估计，证据是具有平移前庭-眼睛反射特征的眼球运动。这些实验将有助于阐明来自半规管的旋转信息如何以即时、在线的方式与重力惯性线索相互作用，以产生对头部方向和反射性前庭眼球运动的知觉估计。这些信息将有助于更好地了解迷路和神经系统疾病患者前庭症状的潜在机制，包括在大多数患者的临床表现中占主导地位的显著知觉性主诉(眩晕)。

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand how the brain uses information from the vestibular labyrinth to estimate the spatial orientation and motion of the head. Specifically, these experiments will investigate the on-line interaction between rotational cues derived from the semicircular canals and gravito-inertial cues transduced by the otolith organs. Roll tilt psychophysics and eye movements will be measured in rhesus monkeys while rotational cues are acutely manipulated by electrical stimulation of the posterior canal ampullary nerves. Canal cues will be presented in isolation (with the head in different static orientations and with the eyes at different vergence angles) and will also be coupled to visual (optokinetic) and inertial cues. Tilt perception will be measured with a psychophysical task derived from the subjective visual vertical (SVV), a test which is widely used to evaluate patients with vestibular symptoms. We hypothesize: 1) that rotational cues provided by the semicircular canals contribute to the brain's estimate of head orientation, evidenced by a shift in SVV responses during canal activation that is not explainable by changes in torsional eye position; and 2) that by dissociating the actual and estimated direction of gravity relative to the head, electrical activation of the vertical canals will induce an aberrant estimate of linear acceleration, evidenced by eye movements with the characteristics of a translational vestibulo-ocular reflex. These experiments will help to elucidate how rotational information derived from the semicircular canals interacts in an immediate, on-line fashion with gravito-inertial cues to produce perceptual estimates of head orientation and reflexive vestibular eye movements. This information will contribute to a better understanding of the mechanisms underlying vestibular symptomatology in patients with labyrinthine and neurologic disorders, including the prominent perceptual complaints (vertigo) that dominate the clinical presentation in most patients.