Spatiotemporal Integration of Mechanical Information in the Rat Brainstem

 描述(申请人提供)：负责整合多个胡须上的触觉信息的感觉处理的早期阶段仍然知之甚少，尽管经常有丘脑和皮质多个胡须反应的报道。在这里，我们建议通过记录三叉神经脊束核(Spir)吻侧区域的投射神经元来填补多晶须感受野合成的两个主要空白。SpVir是一个接受来自多个胡须的初级传入输入的脑干区。首先，还没有关于SpVir神经元对量化机械刺激的反应的特征。其次，只有一项研究报告了清醒动物中这些神经元的记录，而这项研究并没有试图描述这些神经元的特征。这里提出的工作将填补这两个空白。首先，为了表征这些细胞对仔细量化的空间和时间机械输入的反应，我们将记录麻醉动物的SpVir神经元，同时向胡须提供各种机械刺激。同时，我们将从多个角度记录高速视频，以提取接触过程中胡须的3D形状。这将使我们能够量化所有胡须的接触时间和力输入，并与神经记录进行比较。其次，当清醒的动物执行一系列定位任务时，我们将记录SpVir中的神经元。在清醒的自然主义探索中，与物体接触的模式发生了巨大的变化，自上而下的调制输入可能会改变接受场结构。当大鼠在不同的物理刺激下执行定位任务时，我们将同时从多个单个神经元进行记录。利用多角度高速录像，我们将确定不同物体在自然调查过程中的接触模式。然后，我们将比较接触模式和神经放电，以确定清醒探索期间感受野的空间结构和时间结构。这些实验有望填补我们在理解触觉信息时空整合方面的两个明显空白：这些细胞中机械输入和尖峰输出之间的确切关系是什么；以及这些细胞在清醒、行为的动物身上表现出什么一般特征。

 DESCRIPTION (provided by applicant): Early stages of sensory processing responsible for the integration of tactile information across multiple whiskers remains poorly understood despite frequent reports of thalamic and cortical multiwhisker responses. Here we propose to fill two major gaps in the characterization of the synthesis of multiple-whisker receptive field by recording from projection neurons in the rostral region of Spinal Trigeminal Nucleus Interpolaris (SpVir)-a brainstem region which receives primary afferent input from multiple whiskers. First, there has been no characterization of SpVir neuron responses to quantified mechanical stimuli. Second, only one study reported recording from these neurons in the awake animal and this study did not attempt to characterize these neurons. The work proposed here will fill both these gaps. First, to characterize these cells' responses to carefully quantified spatial and temporal mechanical inputs, we will record from SpVir neurons in the anaesthetized animal while presenting a variety of mechanical stimuli to the whiskers. Simultaneously, we will record high-speed video from multiple angles to extract the 3D shape of the whiskers during contact. This will allow us to quantify contact timing and force inputs to all whiskers and compare to neural recordings. Second, we will record from neurons in SpVir while an awake animal performs a series of localization tasks. During awake, naturalistic exploration, the patterns of contact with objects change drastically and top down modulatory inputs may alter receptive field structure. We will record from multiple single neurons simultaneously while the rat performs localization tasks with varying physical stimuli. Using multiple angle high speed video recordings we will determine the patterns of contact during naturalistic investigation of different objects. We will then compare the contact patterns with neural spiking to determine the spatial and temporal structure of the receptive field during awake exploration. These experiments promise to fill the two glaring gaps in our understanding of spatiotemporal integration of tactile information: what are the precise relationships between mechanical input and spiking output in these cells; and what general characteristics do these cells exhibit in the awake, behaving animal.