MIDBRAIN CIRCUITRY FOR NEURONAL CONTROL OF GAZE

用于注视神经元控制的中脑电路

• 批准号: 6630116
• 负责人: Paul J May
• 金额: $ 28.59万
• 依托单位: UNIVERSITY OF MISSISSIPPI MED CTR
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6630116
• 关键词: Macaca; behavioral /social science research tag; brain stem; electron microscopy; fluorescent dye /probe; head movements; immunocytochemistry; light microscopy; mesencephalon; motor neurons; neural information processing; neuroanatomy; neurons; neuroregulation; reticular formation; saccades; smooth pursuit eye movement; superior colliculus; synapses; tegmentum; visual feedback; visual fixation; visual perception

DESCRIPTION (provided by applicant): Humans, as foveate creatures, continuously examine their environment through a series of gaze changes involving saccadic eye movements and, in many cases, quick accompanying head movements. Normal visual perception requires that these movements be accurate and precisely coordinated. Consequently, neurological disorders that interfere with gaze are quite debilitating, often producing symptoms that result in the initial clinical visit. Our long-term goal is to analyze the circuitry underlying gaze. The central mesencephalic reticular formation (cMRF) represents the major midbrain target of the superior colliculus (SCol), and is believed to provide input to brainstem visual motor structures, and the spinal cord, in addition to feeding back upon the SCoI. cMRF stimulation elicits gaze changes, and this region contains several different physiological cell types that fire before saccadic eye movements. However, our knowledge of cMRF connectivity is limited. In this study, a series of dual tracer experiments will be undertaken in macaque monkeys to define cMRF connections with reticulospinal neurons in the medulla, motoneurons in the spinal cord, SCol neurons projecting in the predorsal bundle, and with the paramedian pontine reticular formation (PPRF). These projections will be tested utilizing post-embedding immunohistochemistry to determine whether they are GABAergic (inhibitory). Multiple fluorescent tracer injections will be utilized to determine whether separate neuronal populations provide inputs to the SCol, PPRF, and head movement centers in the medulary reticular formation and cervical cord. In addition, these cMRF neurons will be characterized with respect to their collicular input. Light and electron microscopic analysis of the dual tracer experiments will allow input/output relationships in the cMRF and its targets to be specified at the neuronal level. The results from these experiments will test the hypothesis that the cMRF provides the SCol with separate channels to modulate the eye and head components of gaze. In addition, they will provide an understanding of the cMRF and SCol circuitry at the neuronal level that can help delineate the feasibility of current and future models of gaze generation. Thus, this study will provide a scientific basis for better understanding gaze mechanisms and pathology.

描述（由申请人提供）：人类作为中央凹生物，通过一系列涉及眼球扫视运动的注视变化来不断检查他们的环境，在许多情况下，还包括快速伴随的头部运动。正常的视觉感知要求这些运动准确且精确协调。因此，干扰凝视的神经系统疾病会让人非常衰弱，通常会产生导致初次临床就诊的症状。我们的长期目标是分析凝视背后的电路。中央中脑网状结构 (cMRF) 代表上丘 (SCol) 的主要中脑目标，除了对 SCoI 进行反馈外，还被认为向脑干视觉运动结构和脊髓提供输入。 cMRF 刺激会引起注视变化，该区域包含几种不同的生理细胞类型，这些细胞类型会在眼球扫视运动之前放电。然而，我们对 cMRF 连接性的了解有限。在本研究中，将在猕猴中进行一系列双示踪剂实验，以确定 cMRF 与髓质网状脊髓神经元、脊髓运动神经元、前背束投射的 SCol 神经元以及桥脑旁正中网状结构 (PPRF) 的连接。 ）。这些预测将利用嵌入后免疫组织化学进行测试，以确定它们是否具有 GABA 能（抑制性）。将利用多次荧光示踪剂注射来确定是否有单独的神经元群向髓质网状结构和颈髓中的 SCol、PPRF 和头部运动中心提供输入。此外，这些 cMRF 神经元将根据其丘脑输入进行表征。双示踪剂实验的光和电子显微镜分析将允许在神经元水平上指定 cMRF 及其目标中的输入/输出关系。这些实验的结果将检验以下假设：cMRF 为 SCol 提供单独的通道来调节凝视的眼睛和头部成分。此外，他们还将提供对神经元水平上的 cMRF 和 SCol 电路的理解，这有助于描述当前和未来凝视生成模型的可行性。因此，这项研究将为更好地理解凝视机制和病理学提供科学基础。