Multisensory integration and self-motion perception in primate vestibular cortex

项目摘要 在脊椎动物中，前庭系统（主要被称为大脑的“平衡系统”） 头部运动和方向信号，为生物体提供自我运动的感觉。的重要贡献 前庭系统对姿势、凝视和步态的反射性控制的特征很好;然而， 关于高级前庭功能的神经基质，如自我感知， 运动和对空间方位的意识。这些功能依赖于大脑皮层整合 前庭输入与躯体感觉和视觉输入。在非人类灵长类动物中，顶岛前庭 皮层（PIVC）是唯一适合执行这种多感觉整合。不像其他前庭敏感皮层 PIVC可以直接进入前庭，体感和来自丘脑的视觉输入;事实上，它是 假设其他前庭皮质区从PIVC接收前庭输入，从而使其成为一个连接 更高级的前庭功能。尽管其假设的重要性，很少有人知道 PIVC整合前庭和前庭外输入的神经机制，以及这种整合 是上下文相关的。例如，目前尚不清楚PIVC神经元是否区分前庭输入， 在被动与主动运动期间产生;这种分化见于前庭核和丘脑 并且被认为是产生运动代理感所必需的。为了研究这些问题，我建议 进行高密度神经生理记录行为灵长类动物在被动刺激和 主动产生的头部和全身运动。在目标1中，我将研究PIVC如何被动地集成 应用前庭和躯体感觉输入（目标1.1），然后是前庭和视觉输入（目标1.2）。在目标2中，我 将研究PIVC是否在被动和主动运动期间差异处理前庭输入。 具体来说，我将研究PIVC如何处理自然自我运动过程中产生的前庭输入（即，表示“自” 以转头任务的形式依赖于感觉运动输入的运动，目标2.1）。然后我将研究如何PIVC 处理在学习过程中产生的前庭输入，认知要求运动任务（目标2.2）。在这两个目标中， 我将确定PIVC中的单个神经元是如何编码前庭和前庭外输入的， 信息是在人口一级提供的。拟议的实验将解决两个问题， 是理解PIVC功能的基础：1）PIVC如何整合多感觉输入以构建一个 自我运动的能力？2）PIVC神经元对自我运动的处理是否与 提供一种运动代理的感觉？此外，所提出的实验将确定感觉运动和 自我运动的认知感知在PIVC中表示。这项研究将提供新的见解， 前庭功能，以及它如何支持高阶过程，使灵长类动物（包括人类和非人类）， 人类）成功地感知和导航他们的环境。

Project Summary In vertebrate animals, the vestibular system (primarily known as the “balance system” of the brain) interprets head-movement and orientation signals to provide organisms with a sense of self-motion. The vital contribution of vestibular system to reflexive control of posture, gaze, and gait is well characterized; however, far less is known about the neural substrates underlying higher-order vestibular functions, such as the perception of self- motion and the awareness of one's orientation in space. These functions rely on the cortical integration of vestibular input with somatosensory and visual input. In non-human primates, the parieto-insular vestibular cortex (PIVC) is uniquely suited to perform this multisensory integration. Unlike other vestibular-sensitive cortical areas, PIVC has direct access to vestibular, somatosensory, and visual input from the thalamus; indeed, it is hypothesized that other vestibular cortical areas receive their vestibular input from PIVC, thus making it a nexus for higher-order vestibular function. Despite its hypothesized importance, extremely little is known about the neural mechanisms by which PIVC integrates vestibular and extra-vestibular input, and whether this integration is context dependent. For example, it is unclear whether PIVC neurons differentiate between vestibular input generated during passive vs. active movements; such differentiation is seen in the vestibular nuclei and thalamus and is thought to be essential for producing a sense of motor agency. To investigate these issues, I propose to conduct high-density neurophysiological recordings in behaving primates during both passive stimulation and actively generated head and whole-body movement. In Aim 1, I will investigate how PIVC integrates passively applied vestibular and somatosensory input (Aim 1.1) and then vestibular and visual input (Aim 1.2). In Aim 2, I will investigate whether PIVC differentially processes vestibular input during passive and active movement. Specifically, I will examine how PIVC processes vestibular input generated during natural self-motion (i.e., self- motion relying on sensorimotor input in the form of a head-turning task, Aim 2.1). I will then examine how PIVC processes vestibular input generated during a learned, cognitively demanding motor task (Aim 2.2). In both aims, I will determine how individual neurons in PIVC encode vestibular and extra-vestibular input, as well as how this information is represented at the population level. The proposed experiments will resolve two questions which are fundamental to understanding PIVC function: 1) How does PIVC integrate multisensory input to construct a percept of self-motion? and 2) Is the processing of self-motion by PIVC neurons consistent with that required to provide a sense of motor agency? Furthermore, the proposed experiments will determine how sensorimotor and cognitive percepts of self-motion are represented in PIVC. This research will provide new insights into cortical vestibular function and how it supports the higher-order processes that allow primates (both human and non- human) to successfully perceive and navigate their environments.