Spectro-Temporal Plasticity in Primary Auditory Cortex

描述（由申请人提供）：听觉体验可以重塑成年动物听觉皮层中的皮层地图并改变神经元的感受野特性。这种可塑性的确切形式取决于行为的背景，和显着的声学刺激的spectrotemporal功能。这已被证明在我们以前的实验中，“在线”spectrotemporal感受野（STRFs）的快速和全面的特点，同时与动物的行为相结合的生理和行为的方法。实验还对比了STRF可塑性的单细胞在不同的听觉任务，采用各种声学信号与控制的频谱和时间特征。这些结果与运动和其他感觉系统中的适应性可塑性的发现是一致的，并支持这样的假设，即当动物从事不同的听觉行为任务时，听觉皮层细胞的感受野特性可能会发生快速的、依赖于上下文的变化。这种可塑性可能涉及对底层皮层回路的选择性功能重塑，以塑造完成当前听觉任务的最有效的接收场。是什么潜在的机制导致了这种非凡的功能可塑性？本研究的目的是将A1区任务相关可塑性的研究扩展到包括言语刺激、新的行为范式等在内的各种新的任务（对比辨别与识别），以探索PEG和周围区域的高阶听觉皮层领域的可塑性，最后探讨额叶皮层自上而下的信号在调节听觉皮层适应性可塑性中的可能作用。我们提出了严格的假设，即额叶皮层神经元编码任务规则，期望，目标和任务相关的意义的声音刺激，并进一步，当一个动物执行不同的听觉任务，从额叶区的自上而下的影响有助于诱导快速适应可塑性听觉皮层，这反映了两个刺激的性质和任务的目标。我们还将进行我们的生理实验与阵列的平面和层状微电极阵列我们的初步研究，从同步神经元记录的单个单位和局部场电位在听觉和额叶皮层已经导致令人兴奋的新的见解，这可能会导致在理解的进展，扩大神经元网络内的相互作用，引起适应性可塑性。

DESCRIPTION (provided by applicant): Auditory experience can reshape cortical maps and transform receptive field properties of neurons in the auditory cortex of the adult animal. The exact form of this plasticity depends on the behavioral context, and the spectrotemporal features of the salient acoustic stimuli. This has been shown by combined physiological and behavioral approaches in our previous experiments in which "on-line" spectrotemporal receptive fields (STRFs) were rapidly and comprehensively characterized simultaneous with the animal behavior. The experiments also contrasted STRF plasticity in single cells across different auditory tasks employing various acoustic signals with controlled spectral and temporal features. These results are consistent with findings of adaptive plasticity in the motor and other sensory systems and support the hypothesis that auditory cortical cells may undergo rapid, context-dependent changes of their receptive field properties when an animal is engaged in different auditory behavioral tasks. This kind of plasticity would likely involve a selective functional reshaping of the underlying cortical circuitry to sculpt the most effective receptive fild for accomplishing the current auditory task. What are the underlying mechanisms that give rise to this extraordinary functional plasticity? The goals of the proposed research are to extend our studies of task-related plasticity in A1 to a variety of new tasks involving speech stimuli, new behavioral paradigms (contrasting discrimination versus recognition), to explore plasticity in the higher order auditory cortical fields of the PEG and surrounding areas, and finally to investigate the possible role of top-down signals from frontal cortex in modulating adaptive plasticity in the auditory cortex. We propose to rigorously test the hypothesis that frontal cortical neurons encode task rules, expectancies, goals and the task-related meaning of acoustic stimuli, and further, that when an animal performs different auditory tasks, top-down influences from frontal areas contribute to the induction of rapid adaptive plasticity in auditory cortex, that reflects boh the nature of the stimuli and goals of the tasks. We shall also conduct our physiological experiments with arrays of planar and laminar microelectrode arrays Our preliminary studies from simultaneous neuronal recordings of single units and local field potentials in auditory and frontal cortex have already lead to exciting new insights, that may lead to progress in understanding the interactions within an extended neuronal network that give rise to adaptive plasticity.