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，以提供具有表征的更高阶段的处理，最终产生感知和记忆，以及用于运动控制的反馈。空间和时间转换的各个阶段的处理和相应的作用之间的相互作用的子群体的兴奋性和抑制性神经元的通路内执行这些转换还没有得到很好的理解。我们建议通过在大鼠触须（须）系统的丘脑皮层通路中的细胞外记录和相应的空间和时间动力学的功能建模的组合来量化体感通路中触觉模式的丘脑和皮层转化。触须系统是一种精致的主动感觉模式，大鼠可以使用该模式来基于单独的触须探索来区分非常相似的纹理表面，AN作为一个很好的模型系统，用于理解感觉刺激到丘脑和皮层表征的转换，这些表征最终引起感知。这项工作的具体目标是：1）量化在自然触觉刺激的编码期间由丘脑和皮层的非线性时间动力学引起的变换，2）量化在自然触觉刺激的编码期间丘脑和皮层中的非线性时空变换，和3）确定在何种程度上这些模式的刺激可以预测从已知的功能特性的丘脑皮层电路通过生物启发模型和估计技术专注于非线性动力学。这些转化的表征在通过中枢神经系统中的工程假体装置控制神经元功能方面是至关重要的，以便在外围装置不可能或不合适时为由于疾病或创伤而失去感觉功能的个体提供帮助。

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.