SOMATOSENSORY CORTEX & THALAMUS

我们的目标是研究在人类和非人类灵长类动物，复杂的灵长类动物的行为，如手动灵巧，双边协调的手，多模式整合，和感觉运动整合所需的目标导向达到的贡献的躯体感觉系统。 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，我们必须揭示我们感觉系统的组织细节，以及支持复杂功能的神经回路。对外侧沟（LS; SII，PV，VS，7 b和RL）中的皮质场的研究表明，它们参与触觉辨别，触觉识别，注意力以及双手单侧和双侧输入的整合。 后顶叶皮层（PP; 5区，7a区，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地形组织的皮质领域，感受野的大小，刺激偏好，和详细的地形连接模式的领域在LS和PP在猴子，并确定是否存在类似的领域在人类。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，我们将记录来自LS和PP中皮质区域中神经元簇的细胞外信号，以响应可量化的、可再现的刺激，例如手部无毛表面上的小凹痕、毛发的移位、在不同方向上沿手部无毛表面沿着的轻划、压力、肌肉操作以及手指、手腕和手部运动。 在这些相同的猴子中，将解剖示踪剂放入电生理学定义的分区中，然后使用多单元电生理记录技术映射目标结构，从而确定皮质内、胼胝体和丘脑连接的详细模式。最近，已经确定，功能磁共振成像技术可以有效地用于人类，以确定地形组织的领域，以及分区的数量在一个区域的皮层。 在我们对猴子进行电生理学和连接研究的同时，我们将利用功能磁共振成像技术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由我们在猴子身上的结果来指导。 因此，我们将开始与上述刺激一样，并直接在LS和PP皮质区的努力。 将我们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，以包括更复杂的任务，包括双边操作，目标导向的达成和多模式整合。 这项研究代表了联合收割机从人类和非人类灵长类动物的研究结果的第一次努力之一，并承诺提供一个更丰富的理解体感皮层，其贡献更高的知觉和认知处理。

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.