Heading Signals in the Visual Area V6

 描述（由申请人提供）：导航我们的环境是一个关键的行为，需要适当的自我运动（航向）的感知。考虑到航向的重要性，许多皮层区域都必须参与其中。阐明整个皮层网络将需要一个系统的 评估像V6这样的候选皮层区域。在这项授权中，我提出了一个彻底的V6神经元活动响应各种标题信号的特性。 在目标1中，我将记录V6神经元以确定对光流（视觉）、黑暗中的平台运动（前庭）以及两个航向信号的相干组合（视觉+前庭）的反应。我将使用同样的刺激，这些刺激在评估处理航向信号的其他皮层区域（如背内侧上级颞区（MSTd）和腹侧顶内区（VIP））的神经元时很有价值，从而可以进行有价值的直接比较。在目标2中，我将 测试V6神经元的参考系的调谐是否对于视觉、前庭以及视觉和前庭航向线索的一致组合的眼睛位置的变化保持不变。参照框架帮助我们理解不同感觉形态之间的行为协调。直觉上，由于我们感知到相对于头部/身体参考系的航向，因此可以合理地假设感觉航向信号将被转换为头部/身体参考系。然而，在MSTd和VIP中，视觉航向信号是以眼睛为中心的，这使得需要对航向参考系进行明确的测试。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。方向依赖性视差调谐（DDD）MSTd神经元已经被牵连使用运动视差作为航向线索。然而，以前评估DDD神经元时，聚散角从未变化。由于DDD神经元是在单一固定距离下评估的，因此不确定DDD细胞的调谐曲线是否与绝对距离或绝对视差有关。后者是必需的， DDD神经元的调谐曲线随观察距离（聚散角）不变。 总的来说，我们有兴趣了解与航向有关的皮层区域的完整网络。实现这一目标需要对候选皮层区域（如V6）进行系统评估。由于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见解，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.