Multisensory integration and self-motion perception in primate vestibular cortex

项目摘要 在脊椎动物中，前庭系统(主要称为大脑的“平衡系统”)解释 头部运动和方位信号，为生物体提供自我运动感。最重要的贡献 前庭系统对姿势、凝视和步态的反射控制有很好的特点；然而，远没有。 已知高阶前庭功能的神经基础，如自我感知 动作和对自己在空间中的方位的意识。这些功能依赖于大脑皮质的整合 具有体感和视觉输入的前庭输入。在非人灵长类动物中，顶岛前庭 皮层(PIVC)特别适合进行这种多感官整合。与其他对前庭敏感的皮质不同 PIVC可以直接从丘脑获得前庭、躯体感觉和视觉输入；事实上，它是 假设其他前庭皮质区域接受来自PIVC的前庭输入，从而使其成为一个神经节 更高级的前庭功能。尽管它被假设为重要的，但人们对它知之甚少 PIVC整合前庭和前庭外输入的神经机制，以及这种整合 与上下文相关。例如，目前尚不清楚PIVC神经元是否区分前庭输入 在被动和主动运动过程中产生的；这种分化见于前庭核团和丘脑 并被认为是产生一种运动代理感的关键。为了调查这些问题，我建议 对行为灵长类动物进行高密度神经生理记录，包括被动刺激和 积极地产生头部和全身的运动。在目标1中，我将调查PIVC如何被动地整合 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在被动和主动运动过程中是否对前庭输入进行不同处理。 具体地说，我将研究PIVC如何处理在自然自我运动(即，自我运动)过程中产生的前庭输入 运动依赖于以转头任务形式的感觉运动输入，目标2.1)。然后我将研究PIVC是如何 处理在习得的、认知要求高的运动任务中产生的前庭输入(目标2.2)。在这两个目标中， 我将确定PIVC中的单个神经元如何编码前庭和前庭外的输入，以及这是如何 信息是在人口层面上表示的。拟议的实验将解决以下两个问题 是理解PIVC功能的基础：1)PIVC如何整合多感觉输入来构建 对自我运动的感知？2)PIVC神经元对自我运动的处理是否与所需的一致 提供一种马达代理的感觉？此外，拟议的实验将确定感觉运动和 自我运动的认知知觉在PIVC中表现出来。这项研究将提供对大脑皮层的新见解 前庭功能以及它如何支持灵长类动物(包括人类和非人类)的高级突起 人类)来成功地感知和导航它们的环境。

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.