Vestibular influences on spatial orientation

描述（由申请人提供）：该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。具体来说，这些实验将研究来自半规管的旋转信号和耳石器官转导的重力惯性信号之间的在线相互作用。通过电刺激后管壶腹神经对旋转信号进行剧烈操纵，测量恒河猴的滚动倾斜心理物理和眼球运动。运河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），也将与视觉（光动力学）和惯性线索耦合。倾斜感知将通过主观视觉垂直（SVV）衍生的心理物理任务来测量，这是一项广泛用于评估前庭症状患者的测试。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，在半规管激活期间SVV反应的变化证明了这一点，而这种变化不能用扭转眼位的变化来解释；2)通过分离相对于头部的实际和估计的重力方向，垂直通道的电激活将引起对线性加速度的异常估计，这可以通过具有平移前庭-眼反射特征的眼球运动来证明。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，从而产生对头部方向和反射性前庭眼运动的感知估计。这一信息将有助于更好地理解迷路和神经系统疾病患者前庭症状的机制，包括在大多数患者中主导临床表现的突出的知觉主诉（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.