Heading Signals in the Visual Area V6

 描述(由申请人提供)：导航我们的环境是一种关键的行为，需要正确的自我运动感知(标题)。鉴于标题的重要性，必须涉及许多大脑皮层区域。完整的皮质网络的阐明将需要一个系统的 评估V6等候选皮质区域。在这项授权中，我建议对V6神经元对不同方向信号的反应进行彻底的表征。在目标1中，我将记录V6神经元，以确定对光流(视觉)、黑暗中平台运动(前庭)以及两个方向信号的连贯组合(视觉+前庭)的反应。我将使用同样的刺激来评估其他皮质区域中处理航向信号的神经元，例如背侧内侧上颞区(MSTd)和腹侧顶内区(VIP)，从而进行有价值的直接比较。在《目标2》中，我会 测试V6神经元参考帧的调谐是否对视觉、前庭以及视觉和前庭方向线索的一致组合的眼睛位置的变化保持不变。参照系帮助我们理解行为是如何在不同的感觉模式之间协调的。直观地说，由于我们是相对于头部/身体参照系感知航向的，所以可以合理地假设感觉航向信号将被转换为头部/身体参照系。然而，在MSTd和VIP中，视觉航向信号都是以眼睛为中心的，因此需要对航向参考帧进行显式测试。在目标3中，我将测试V6利用运动视差作为航向提示的潜力。方向相关视差调节(DDD)MSTd神经元已经被认为使用运动视差作为航向提示。然而，以前评估DDD神经元时，收敛角从未改变。因为DDD神经元是在单一的注视距离上进行评估的，所以DDD细胞的调谐轮廓是否与绝对距离或绝对视差有关尚不确定。后者适用于 DDD神经元的调谐曲线不随观察距离(聚合角)而变化。总体而言，我们有兴趣了解与标题有关的大脑皮层区域的完整网络。要实现这一目标，需要对V6等候选皮质区域进行系统评估。因为航向知觉本质上是一个多感官问题，理解这个系统将不可避免地产生对多感官整合是主要缺陷的损伤的洞察，例如眩晕。

 DESCRIPTION (provided by applicant): Navigating our environment is a critical behavior that requires proper perception of self-motion (heading). Given the importance of heading, many cortical areas must be involved. Elucidation of the full cortical network will require a systematic evaluation of candidate cortical areas like V6. In this grant, I propose a thorough characterization of V6 neuronal activity in response to various heading signals. In Aim 1, I will record from V6 neurons to determine responses to optic flow (visual), platform motion in the dark (vestibular), and the coherent combination (visual+vestibular) of the two heading signals. I will use the same stimuli that have been valuable in evaluating neurons in other cortical areas that process heading signals, such as the dorsal medial superior temporal area (MSTd) and the ventral intraparietal area (VIP), allowing valuable direct comparisons to be made. In Aim 2, I will test whether the tuning of V6 neurons' reference frames remain invariant to changes in eye-position for visual, vestibular, and congruent combination of the visual and vestibular heading cues. Reference frames help us understand how behavior is coordinated among different sensory modalities. Intuitively, since we perceive heading relative to a head/body frame of reference, it is reasonable to assume that sensory heading signals will be transformed to a head/body reference frame. However, in both MSTd and VIP, visual heading signals are eye-centered making explicit testing for heading reference frames necessary. In Aim 3, I will test the potential of V6 to utilize motion parallax as a heading cue. Direction-dependent disparity tuned (DDD) MSTd neurons have already been implicated to use motion parallax as a heading cue. However, the vergence angle was never varied when DDD neurons were previously assessed. Because DDD neurons were evaluated at a single fixation distance, it is uncertain if the tuning profiles of DDD cells relate to absolute distance or absolute disparity. The latter is required for the tuning profiles of DDD neurons to be invariant with viewing distance (vergence angle). Overall we are interested in understanding the full network of cortical areas involved in heading. Accomplishing this goal requires systematic evaluation of candidate cortical areas such as V6. Because heading perception is inherently a multi-sensory problem, understanding this system will invariably produce insights into impairments where multi-sensory integration is a primary deficit, such as vertigo.