NEURAL PATHWAYS INVOLVED IN TACTILE DISCRIMINATION

拟议的研究是一个项目的一部分，该项目的长期目标是增加 对于我们对触觉信息处理能力和 躯体感觉系统的局限性，特别是那些神经区域 以及负责处理源自 机械刺激手部无毛表面的机械刺激具体来说， 建议检查功能特性和刺激反应 投射的三条脊髓通路的单个神经元之间的关系， 直接或间接到达丘脑腹-基底复合体： 脊髓颈束、突触后背柱系统和 脊丘脑束。微电极将被用于记录细胞外 细胞体或纤维对受控机械反应的活性 刺激浣熊前爪无毛的皮肤。神经元将会是 通过逆序识别属于这三个系统中的一个 电刺激脊髓或脑的适当区域 茎。要检查的具体参数包括通道和自适应 属性、绝对阈值和接受场区域，以及 受控机械刺激速度、位移和力的影响 无论是动态放电还是静态放电。此外，还将寻找神经元 它们表现出兴奋或抑制会聚的特性， 以及其显示特征检测器的属性(例如，优先 对边缘或横向移动的刺激的反应)。神经细胞的性质 将对这三条脊椎路径进行相互比较，并与 楔状核初级传入和神经元的特性 丘脑腹基复合体，以前在本实验室研究过。这些 研究应该有助于我们对不同贡献的了解 触觉加工的三条主要体感通路 通过行为上突出的触觉器官系统获得的信息， 前爪或手，尤指其无毛的表面。反过来，这又应该是 提供与设备设计相关的信息以供使用 其他感官障碍的个体的触觉信息 医疗模式。这些发现也应该与神经学上的 脊髓损伤或疾病的鉴别诊断。

The proposed research is part of a project whose long-term goal is to add to our understanding of the tactile information processing capabilities and limitations of the somatosensory system, especially those neural regions and systems responsible for processing tactile information derived from mechanical stimulation of the glabrous surfaces of the hand. Specifically, it is proposed to examine functional properties and stimulus-response relationships of single neurons of three spinal pathways which project, directly or indirectly, to the thalamic ventrobasal complex: the spinocervical tract, the postsynaptic dorsal column system, and the spinothalamic tract. Microelectrodes will be used to record extracellular activity of cell bodies or fibers in response to controlled mechanical stimulation of the glabrous skin of the raccoon's forepaw. Neurons will be identified as belonging to one of these three systems by antidromic electrical stimulation of the appropriate region of spinal cord or brain stem. Specific parameters to be examined include modality and adaptive properties, absolute thresholds, and receptive field areas, as well as effects of controlled mechanical stimulus velocity, displacement, and force on both dynamic and static discharge. Additionally, neurons will be sought which display properties suggesting excitatory or inhibitory convergences, and which display properties of feature detectors (e.g., preferential response to edges or laterally moving stimuli). Properties of neurons of the three spinal pathways will be compared with each other, as well as with properties of both primary afferents and neurons of the cuneate nucleus and thalamic ventrobasal complex, previously studied in this laboratory. These studies should contribute to our knowledge of the differential contribution of three major somatosensory pathways to the processing of tactile information acquired by a behaviorally salient tactile organ system, the forepaw or hand, especially its glabrous surfaces. This, in turn, should provide information relevant to the design of devices for the utilization of tactile information by individuals handicapped in other sensory modalities. Findings should also have neurological relevance to the differential diagnosis of spinal cord injury or disease.