Sensory and integrative properties of the fast visuomotor system

人类在很大程度上是视觉动物;视觉是我们用来识别外部世界感兴趣的对象的主要感觉。为了执行准确的视觉动作，来自外部世界的视觉信息需要快速地情境化并与当前的身体姿势整合，以生成有效且适当的运动命令。先前的研究已经表明，这种情境化和整合可以通过能够在视觉事件的小于150 ms内发起运动的快速可视化系统（例如，例如接住落下的水杯的校正动作）。对颈部和四肢肌肉活动的精确记录为刺激锁定反应（SLR）提供了证据，SLR是在视觉刺激后约80-100 ms发生的运动开始之前的肌肉活动的小爆发。我们的假设是，SLR是通过上级丘介导的快速视觉系统的信号，上丘是定向的关键中脑结构。**拟议的研究的目标是通过检查上肢肌肉中的SLR来更好地理解快速视觉系统，因为人类执行平面伸展运动。在两个项目中的第一个项目中，我们的目标是更好地了解SLR的感官特性。到目前为止，SLR已经引起了简单的点状视觉刺激孤立地提出。在这里，我们将在呈现更精细的视觉刺激（例如，改变空间频率，提供刺激运动），或复杂环境（例如，呈现多个刺激，或改变眼睛和手的初始位置）。该项目的研究结果将提供有关视觉处理和SLR潜在途径的信息。在第二个项目中，我们将研究当参与者在不同的行为背景下接触时，SLR的整合特性。例如，当参与者远离刺激，突然取消即将到来的动作，在改变的视觉-运动环境中移动，或在不确定的选择之间做出决定时，将研究SLR。总之，该项目的结果将提供关于SLR如何与随后的行为相关的功能性见解，并反映参与者在各种不同任务中的认知状态。本提案的总体目标是从感官角度更好地理解SLR，因为项目1的结果将提供有关视觉处理的程度和时间的信息，以及功能角度，因为项目2的结果将澄清SLR如何与随后的行为相关。SLR的一个特别独特的方面是，它可以在人类身上进行一次又一次的试验;因此，我们可以利用许多通常为动物神经生理学保留的工具来更好地了解快速视觉系统对人类行为的贡献。********

Humans are largely visual animals; vision is the main sense we use to identify objects of interest in our external world. In order to execute accurate visual actions, visual information from the outside world needs to be rapidly contextualized and integrated with current body posture to generate efficient and appropriate motor commands. Previous research has shown that such contextualization and integration can be carried out remarkably quickly by a fast visuomotor system capable of initiating a movement in less than 150 ms of a visual event (e.g., such as a corrective action to catch a falling cup of water). Precise recordings of neck and limb muscle activity have provided evidence for stimulus-locked responses (SLR), which are small bursts of muscle activity well in advance of movement onset that occur time-locked ~80-100 ms after visual stimuli.Our hypothesis is that SLRs are a signature of the fast visuomotor system mediated through the superior colliculus, a key midbrain structure for orienting.******The goal of the proposed research is to better understand the fast visuomotor system by examining the SLR in upper limb muscles, as humans execute planar reaching movements. In the first of two projects, we aim to better understand the sensory properties of the SLR. To date, the SLR has been elicited by simple punctate visual stimuli presented in isolation. Here, we will investigate the SLR following the presentation of more refined visual stimuli (e.g., varying spatial frequencies, providing stimulus motion), or complex environments (e.g., presenting multiple stimuli, or varying initial position of the eyes and hand). The findings from this project will provide information about the visual processing and pathways underlying the SLR.***In the second project, we will study the integrative properties of the SLR while participants reach in different behavioural contexts. For example, the SLR will be studied when participants move away from a stimulus, abruptly cancel an upcoming action, move in an altered visual-to-motor environment, or make a decision between uncertain alternatives. Together, the results from this project will provide functional insights into how the SLR relates to ensuing behaviour, and reflects the participant's cognitive state in a variety of different tasks.***The overall objective of this proposal is to better understand the SLR from both a sensory perspective, as the results from project 1 will provide information about the extent and timing of visual processing, and a functional perspective, as the results from project 2 will clarify how the SLR relates to ensuing behaviour. One of the particularly unique aspects of the SLR is that it is available on a trial-by-trial basis in humans; accordingly, we can leverage many of the tools normally reserved for animal neurophysiology to better understand the contribution of the fast visuomotor system to human behaviour. ********