SOMATOSENSORY CORTEX & THALAMUS

我们的目标是研究在人类和非人类灵长类动物中，体感系统对复杂灵长类动物行为的贡献，如手工灵巧、双手的双边协调、多模态整合和目标定向到达所需的感觉运动整合。人类这些能力的进化与我们的感觉和运动系统的进化交织在一起。为了理解这些复杂的行为是如何产生的，我们必须揭示我们的感觉系统组织的细节，以及支持复杂功能的神经回路。对外侧沟皮层场（LS、SII、PV、VS、7b和RL）的研究表明，外侧沟参与了触觉辨别、触觉识别、注意以及手部单侧和双侧输入的整合。后顶叶皮质区域（PP；区域5,7a， LIP和VIP）参与产生定向运动、注意力和多模态整合的运动坐标。我们的研究旨在揭示猴脑皮层场的地形组织、感受野大小、刺激偏好以及脑皮层场和脑皮层场的详细地形连接模式，并确定人类是否存在类似的脑皮层场。我们的建议结合了几种数据收集技术。在非人类灵长类动物中，我们将记录下LS和PP皮层区神经元簇对可量化的、可重复的刺激的细胞外反应，这些刺激包括手无毛表面上的小凹痕、毛发的位移、沿着手无毛表面不同方向的轻触、压力、肌肉操纵以及手指、手腕和手的运动。在这些相同的猴子中，皮层内、胼胝体和丘脑连接的详细模式将通过将解剖示踪剂放置在电生理学定义的细分中，然后使用多单元电生理学记录技术绘制目标结构来确定。最近，已经确定功能磁共振成像技术可以有效地用于人类确定领域的地形组织，以及皮层区域内的细分数量。在对猴子进行电生理和连接研究的同时，我们将利用功能磁共振成像技术来探索人类新皮层的类似区域。我们的刺激选择和感兴趣的领域将以我们在猴子身上的结果为指导。因此，我们将从如上所述的刺激开始，并将我们的努力指向左脑和左脑皮层的区域。将在猴子模型中建立的皮层场和连接模式的框架应用于人类，我们可以扩展我们的刺激库，包括更复杂的任务，包括双边操作、目标定向到达和多模态整合。这项研究是首次将人类和非人类灵长类动物的研究结果结合起来，并有望提供对躯体感觉皮层的更丰富的理解，以及它对更高的感知和认知处理的贡献。

Our goal is to examine in human and non-human primates, the contribution of the somatosensory system to complex primate behaviors such as manual dexterity, bilateral coordination of the hands, multimodal integration, and sensorimotor integration required for goal directed reaching. The evolution of these abilities in humans is intertwined with the evolution of our sensory and motor systems. In order to understand how these sophisticated behaviors are generated, we must uncover the details of the organization of our sensory systems, and the neural circuitry that subserves complex functions. Studies of cortical fields in the lateral sulcus (LS; SII, PV, VS, 7b, and RL) indicate that they are involved in tactile discrimination, tactile recognition, attention, and integration of unilateral and bilateral inputs across the hands. Areas in posterior parietal cortex (PP; areas 5, 7a, LIP and VIP) are involved in generating motor coordinates for directed movements, attention, and multimodal integration. Our studies are aimed at uncovering the topographic organization of cortical fields, receptive field size, stimulus preference, and detailed topographic connection patterns of fields in LS and PP in monkeys, and determining if similar fields exist in humans. Our proposal combines several data collection techniques. In non-human primates we will record extracellularly from clusters of neurons in cortical fields in LS and PP in response to quantifiable, reproducible stimuli such as small indentations on the glabrous surface of the hand, displacement of hairs, light strokes along the glabrous surface of the hand in different directions, pressure, muscle manipulation, and digit, wrist and hand movements. In some of these same monkeys, the detailed patterns of intracortical, callosal, and thalamic connections will be determined by placing anatomical tracers into electrophysiologically defined subdivisions, and then mapping target structures using multiunit electrophysiological recording techniques. Recently, it has been established that the fMRI technique can be used effectively in humans to determine the topographic organization of fields, and the number of subdivisions within a region of cortex. In parallel with our electrophysiological and connection studies in monkeys, we will utilize fMRI techniques to explore similar regions of the neocortex in humans. Our stimulus selection and areas of interest will be guided by our results in monkeys. Thus, we will begin with stimulation like that described above, and direct our efforts to areas in the LS and PP cortex. Applying the framework of cortical fields and patterns of connections established in our monkey model to humans, we can expand our stimulus repertoire to include more sophisticated tasks which involve bilateral manipulation, goal directed reaching, and multimodal integration. This study represents one of the first efforts to combine results from human and non-human primate studies, and promises to provide a richer understanding of somatosensory cortex, and its contribution to higher perceptual and cognitive processing.