STIMULUS-SPECIFIC SI CORTICOCORTICAL INTERACTIONS

将在完整受试者以及缺乏脊髓背柱或脊髓丘脑投射通路的受试者中研究两种不同（无害机械与热）自然皮肤刺激模式对对侧SI皮质的影响。麻醉的松鼠猴将作为实验对象。在每名受试者中，将使用近红外光学固有信号（OIS）成像和细胞外微电极记录方法的组合来获得关于SI神经元群体和单个神经元对两种皮肤刺激模式的反应的信息。在每一个主题的记录的尖峰放电活动引起从单个SI神经元的皮肤刺激的每一个模型。在每个受试者中，通过每种模式的皮肤刺激从单个SI神经元诱发的尖峰放电活动的尖峰放电活动的记录将从位于功能上相反的SI区域（例如，皮肤刺激诱发增加的区域与经历活动减少的区域）中的神经元获得。微电极穿透将由SI光学响应的高分辨率OIS图像引导，该SI光学响应与用于引起单个神经元放电活动的刺激相同。在一些实验中，将药物直接应用于大脑皮层或脊髓将用于区分大脑皮层与背角的NMDA受体系统中的活性对SI反应的贡献。该项目预计将产生新的信息刺激导向的皮质-皮质相互作用的贡献SI信息处理和somesthesis。这一发现也应该与目前的中枢神经系统的非伤害性感受和疼痛机制的理论有关

The effects on the contralateral SI cortex of two different (non-noxious mechanical versus thermal) modes of natural skin stimulation will be studied in intact subjects, and also in subjects lacking either the spinal dorsal column or spinothalamic project pathways. Anesthetized squirrel monkeys will serve as subjects. In each subject a combination of the methods of near-infrared optical intrinsic signal (OIS) imaging and extracellular microelectrode recording will be used to obtain information about the SI neuron population and single neuron responses to the two modes of skin stimulation. In each subject recordings of the spike discharge activity evoke from single SI neurons by each model of skin stimulation. In each subject recordings of the spike discharge activity of the spike discharge activity evoked from single SI neurons by each mode of skin stimulation will be obtained from neurons located in functionally contrasting SI regions (e.g. regions in which the skin stimulus evokes increased vs. regions which undergo a decrease in activity. The microelectrode penetrations will be guided by high-resolution OIS images of the SI optical response to the same stimuli used to evoke single neuron discharge activity. In some experiments direct application of drugs to cerebral cortex or to spinal cord will be used to distinguish the contributions to the SI responses of activity in the NMDA receptor systems of cerebral cortex versus dorsal horn. The project is expected to generate novel information about the contributions of stimulus-directed cortico-cortical interactions to SI information processing and somesthesis. The findings also should bear on current theories of the CNS mechanisms of nonciception and pain