SENSORY PROCESSING AND ITS RELATION TO ORAL-FACIAL PAIN

中枢神经系统的感觉处理涉及上行和 和下降路径。 例如，上升的伤害性冲动 介导口腔面部疼痛，受下行控制系统影响 主要起源于脑干。 在视觉系统中，上升 来自视网膜的脉冲受到下行控制系统的影响 起源于皮质。 拟议的研究考察了 下行调节通路和上行感觉通路。 第一阶段。下降到上丘的纤维来自广泛的 广阔的前纹状皮层、颞叶皮层和顶叶皮层。 电生理学 对猴子的行为研究表明，这种皮层系统 在视觉运动整合中起着重要的调节作用。 个人 该系统的组件源自每个已知的细分 视觉皮层。 皮质细胞的每个成分可能形成独特的 视觉主题区域内的细胞亚群 起源。 我们第一阶段的目标是检查这样一个组件，即： 来自纹外区 MT 的皮质顶盖通路。 视觉反应 MT 中单个皮质细胞的特性将通过以下方法进行检查 麻醉猴子的微电极记录，并与 控制不投射到丘的 MT 细胞群。 第二阶段。 来自口腔的上行伤害性信息是 通过浅层的长投射神经元传递到丘脑 髓背角的层和第五层。 我们第二阶段的目标是 确定无髓鞘初级传入突触是否 椎板 V 的三叉丘脑细胞。三叉丘脑神经元，已鉴定 通过对侧丘脑的逆向激活，将被填充 与辣根过氧化物酶（HRP）和无髓鞘初级末端 传入纤维将用注射的顺向运输的 HRP 进行标记 进入背根神经节。 填充细胞的形态特征 将描述这些细胞之间的突触相互作用 将分析标记的终端。

Sensory processing in the central nervous system involves both ascending and descending pathways. For example, ascending nociceptive impulses which mediate oral-facial pain, are influenced by descending control systems originating mainly in the brain stem. In the visual system, ascending impulses from the retina are influenced by descending control systems originating in the cortex. The proposed research examines both a descending modulatory pathway and an ascending sensory pathway. Phase I. Fibers descending to the superior colliculus arise from a wide expanse of prestriate, temporal and parietal cortex. Electrophysiological and behavioral studies in monkeys indicate that this corticotectal system plays an important modulatory role in visuomotor integration. Individual components of this system descend from each of the known subdivisions of visual cortex. Corticotectal cells of each component may form a unique subpopulation of cells within the visuotopic area from which they originate. Our goal in Phase I is to examine one such component namely, the corticotectal pathway from extrastriate area MT. The visual response properties of individual corticotectal cells in MT will be examined with microelectrode recordings in the anesthetized monkey, and compared to a control population of MT cells which do not project to the colliculus. Phase II. Ascending nociceptive information from the oral cavity is relayed to the thalamus by long projection neurons in the superficial layers and lamina V of the medullary dorsal horn. Our goal in Phase II is to determine whether unmyelinated primary afferents synapse on trigeminothalamic cells of lamina V. Trigeminothalamic neurons, identified by antidromic activation from the contralateral thalamus, will be filled with horseradish peroxidase (HRP), and terminals of unmyelinated primary afferent fibers will be labeled with orthogradely transported HRP injected into the dorsal root ganglion. The morphological features of filled cells will be described and the synaptic interaction between these cells and labeled terminals will be analyzed.