Nonlinear Thalamocortical Transformations

描述（由申请人提供）：大脑中感觉处理的早期阶段的作用是转换感觉世界中的信号，为更高阶段的处理提供表征，最终产生感知和记忆，以及运动控制的反馈。不同处理阶段的空间和时间转换以及通路中兴奋性和抑制性神经元亚群之间相互作用在执行这些转换中的相应作用尚未得到很好的理解。我们建议通过结合大鼠触须（须）系统丘脑皮质通路的细胞外记录和相应时空动态的功能建模，量化体感觉通路中触觉模式的丘脑和皮层转换。触须系统是一种精致的主动感觉模式，大鼠可以仅基于触须探索来区分非常相似的纹理表面。An是理解感觉刺激转化为丘脑和皮层表征并最终产生知觉的一个很好的模型系统。这项工作的具体目标是：1)量化自然触觉刺激编码过程中丘脑和皮层的非线性时间动态引起的转换；2)量化自然触觉刺激编码过程中丘脑和皮层的非线性时空转换；3)通过生物物理模型和非线性动力学估计技术，确定这些刺激模式在多大程度上可以从已知的丘脑皮质回路功能特性中预测出来。这些转化的特征对于通过中枢神经系统的工程假肢装置控制神经元功能至关重要，以便为由于疾病或创伤而失去感觉功能的个体提供帮助，当周围装置不可能或不合适时。

DESCRIPTION (provided by applicant): The role of the early stages of sensory processing in the brain is to transform signals in the sensory world to provide higher stages of processing with representations that eventually give rise to perception and memory, as well as feedback for motor control. The spatial and temporal transformations by the various stages of processing and the corresponding role of the interplay between sub-populations of excitatory and inhibitory neurons within the pathway in performing these transformations are not well understood. We propose to quantify thalamic and cortical transformations of tactile patterns in the somatosensory pathway through a combination of extracellular recording in the thalamocortical pathway of the rat vibrissa (whisker)system and functional modeling of the corresponding spatial and temporal dynamics, The vibrissa system is an exquisite active sensory modality that rats can use to discriminate between very similarly textured surfaces based on vibrissal exploration alone, an serves as an excellent model system for understanding the transformations of sensory stimuli into thalamic and cortical representations that eventually give rise to perception. The specific aims of this work are to: 1) quantify the transformations induced by the nonlinear temporal dynamics of the thalamus and cortex during the encoding of naturalistic tactile stimuli, 2) quantify nonlinear spatiotemporal transformations in the thalamus and cortex during the encoding of naturalistic tactile stimuli, and 3) determine to what extent these patterns of stimuli can be predicted from known functional properties of the thalamocortical circuit through both biophysically inspired models and estimation techniques focused on nonlinear dynamics. The characterization of these transformations is critical in controlling neuronal function through engineered prosthetic devices in the central nervous system, in order to provide assistance to individuals who have lost sensory function due to disease or trauma, when peripheral devices are not possible or appropriate.