STIMULUS-SPECIFIC SI CORTICOCORTICAL INTERACTIONS

两种不同的（无害的机械和热）自然皮肤刺激模式对对侧SI皮质的影响将在完整的受试者中进行研究，也将在缺乏脊髓背柱或脊髓丘脑项目通路的受试者中进行研究。被麻醉的松鼠猴将作为实验对象。在每个受试者中，将使用近红外光学本征信号（OIS）成像和细胞外微电极记录相结合的方法来获取SI神经元数量和单个神经元对两种皮肤刺激模式的反应的信息。在每个被试中，每个皮肤刺激模型都记录了单个SI神经元引起的尖峰放电活动。在每个被试中，每一种皮肤刺激模式下单个SI神经元引起的spike放电活动的记录将从位于功能对比的SI区域（例如，皮肤刺激唤起增加的区域与经历活动减少的区域）的神经元中获得。微电极穿透将由SI光学响应的高分辨率OIS图像来指导，这些图像用于引起单个神经元放电活动的相同刺激。在一些实验中，将药物直接应用于大脑皮层或脊髓，以区分大脑皮层和背角的NMDA受体系统活动对SI反应的贡献。该项目有望产生关于刺激导向的皮质-皮质相互作用对SI信息处理和某些合成的贡献的新信息。这些发现也应该与目前关于中枢神经系统的无感觉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