RECEPTIVE FIELDS OF LAYER IV (BARREL FIELD) NEURONS

哺乳动物的感觉系统由来自外周的多条通路组成 大脑皮层的受体。在这些文件中，只有一个是为传输而组织的 感官刺激的精确物理特征。建议数 实验的设计是为了展示并行的组织和功能 躯体感觉通路。初步结果显示，其中 多条躯体通路将信息从胡须传递到 大鼠桶状野皮质，只有丘脑内侧通路 丘脑腹侧后核(VPM)的细分能够 维持桶状野神经元的感觉反应性。这个 一般的论断是通过丘脑的‘副大脑’通路 后核(PO)，终止于皮质桶周围的隔膜， 调节隔区神经元的兴奋性；通过调节水平 大脑皮质中活动传播的距离，PO控制程度 来自VPM的输入之间的交互和关联终止于 分开的桶。为了验证这一假设，我们将认同解剖学 传输方法：大脑皮质内丘疹和丘脑 副语言输入趋于一致。那么我们就来衡量一下 PO对大脑皮层波幅和水平扩展的刺激作用 由一根胡须的运动引起的活动。PO刺激会 与晶须移动同步或异相输送 随着胡须的移动。然后我们将衡量PO的影响 对大脑皮层感受野可塑性的刺激作用 胡须暂时成对的移动。最后，我们将调查 谷氨酸受体在桶野感受野可塑性中的作用。

Sensory systems in mammals consist of multiple pathways from the peripheral receptors to neocortex. Of these, only one is organized for transmitting the precise physical characteristics of sensory stimuli. The proposed experiments are designed to show the organization and function of parallel somatic sensory pathways. Preliminary results indicate that, of the multiple somatic pathways carrying information from the whiskers to the barrel field cortex of rat, only the 'lemniscal' pathway through the medial subdivision of the thalamic ventral posterior nucleus (VPM) is capable of maintaining the sensory responsiveness of neurons in the barrel field. The general thesis is that the 'paralemniscal' pathway through the thalamic posterior nucleus (PO), terminating in septa surrounding cortical barrels, regulates the excitability of septal neurons; by modulating the horizontal distance in cortex across which activity spreads, PO controls the degree of interaction and association between inputs from VPM terminating in separate barrels. To test this hypothesis, we will identify with anatomical transport methods the locations in cortex at which lemniscal and paralemniscal inputs converge. Then we will measure the effect of stimulation of PO on the magnitude and horizontal spread of cortical activity evoked by movement of a single whisker. The PO stimulation will be delivered either synchronously with whisker movement or out of phase with whisker movement. We will then measure the influence of PO stimulation on the plasticity of cortical receptive fields induced by temporally paired movement of whiskers. Finally, we will investigate the role of glutamate receptors in barrel field receptive field plasticity.