Superior colliculus participation in rat vibrissa sensorimotor loops

描述(申请人提供)：解释复杂的感官刺激对正常的人类功能至关重要。许多疾病和障碍，包括自闭症和多动症，都涉及到感觉障碍或异常。这些通常包括对不同类型的简单和复杂刺激的高反应性和低反应性。上丘参与感知听觉、视觉和躯体感觉刺激，被认为参与处理复杂刺激和适当地引导注意力。虽然对涉及上丘的视觉通路的研究已经取得了与感觉运动处理和注意有关的有希望的结果，但这些发现可能会因为关注视觉通道而受到限制。为了充分理解对复杂刺激做出反应的感觉运动过程，我们必须探索其他感觉形式。本研究将以大鼠触觉系统为模型，探讨上丘控制的定向和注意功能与躯体感觉的关系。我们将研究一个假设的闭合感觉运动回路，它将感觉信息转换为运动输出，目的是阐明对单感觉和多感觉刺激产生反应的一般感觉运动转换。我还将测试调节警觉或唤醒状态的机制如何影响这种感觉运动处理。具体目的一：检验顶盖面神经元是触觉感觉运动环路中的变压器的假设。我预测，顶盖面部神经元接受躯体感觉输入，并可以驱动面部神经元的持续放电。为了测试这一点，我将使用体内和体外两种准备方法，研究已识别的顶盖面部神经元的反应特性和相关的生物物理特性。具体目的II：验证脑干胆碱能系统激活增强触顶感觉运动环运作的假说。我预测，胆碱能系统增加了顶盖面部神经元对躯体感觉刺激的反应性，并增强了它们驱动下游运动神经元的能力。我将通过在体内激活胆碱能脑干区域以及在体内和体外应用胆碱能药物来检验这些预测。我们正在研究上丘在对躯体感觉刺激做出适当反应中的作用。这项研究将有助于我们理解人们对简单刺激(如针刺)和复杂刺激(如父母的拥抱)的理解和反应。

DESCRIPTION (provided by applicant): Interpreting complex sensory stimuli is critical for normal human functioning. Many diseases and disorders, including autism and hyperactivity, involve sensory deficits or abnormalities. These commonly include hyper- and hypo-responsiveness to different types of simple and complex stimuli. The superior colliculus, which is involved in sensing auditory, visual, and somatosensory stimuli, is thought to participate in processing complex stimuli and directing attention appropriately. While studies of visual pathways involving the superior colliculus have yielded promising results relating to sensorimotor processing and attention, these findings may be limited by focusing on the visual modality. In order to fully understand the sensorimotor processing occurring in response to complex stimuli, we must explore other sensory modalities. This proposal will explore the orienting and attentive functions controlled by the superior colliculus in relation to somatosensation using the rat vibrissa system as a model. We will investigate a putative closed sensorimotor loop which transforms sensory information into motor output with the goal of elucidating general sensorimotor transformations which generate responses to mono- and multisensory stimuli. I will also test how mechanisms regulating states of vigilance or arousal may affect this sensorimotor processing. Specific Aim I: To test the hypothesis that the tectofacial neurons are the transformer in a vibrissa sensorimotor loop. I predict that tectofacial neurons receive somatosensory input and can drive sustained firing in facial neurons. To test this I will investigate the response properties and relevant biophysical properties of identified tectofacial neurons, using both in vivo and in vitro preparations. Specific Aim II: To test the hypothesis that activation of the brainstem cholinergic system enhances the operation of the vibrissa-tectal sensorimotor loop. I predict that the cholinergic system increases the responsiveness of tectofacial neurons to somatosensory stimuli, and increases their ability to drive downstream motoneurons. I will test these predictions by activating cholinergic brainstem regions in vivo and by applying cholinergic agents in vivo and in vitro. We are investigating the role of the superior colliculus in responding appropriately to somatosensory stimuli. This study will contribute to our understanding of how people interpret and respond to simple (i.e. a pin prick) and complex (i.e. a hug from a parent) stimuli.