Spectro-temporal Plasticity in Primary Auditory Cortex

描述（由申请人提供）：听觉经验可以引起初级听觉皮层（AI）显著和持续的重组和感受野可塑性。这种可塑性的确切形式取决于行为环境的细节，以及声刺激中的光谱和时间线索。最近的研究结果进一步表明，清醒行为动物的人工智能神经元反应反映了运动、注意力和奖励维度，而不是简单地编码刺激的声学特征。这与其他神经系统的研究结果一致，并支持了以下假设：当动物从事不同的听觉行为任务时，听觉皮层细胞可能会经历快速、短期和情境依赖的感受野特性变化。这种可塑性可能涉及到对底层皮层回路的选择性功能重新配置，以塑造最有效的接受野来完成听觉任务。本研究拟通过结合生理/行为实验对这一假设进行探索，在动物行为的同时快速、全面地表征光谱颞感受野（strf）。实验还对比了单个细胞在不同的听觉任务中STRF的可塑性，使用不同的声学信号控制频谱和时间特征。这些独特的能力是通过开发新的波纹刺激来参与动物行为，同时快速测量其皮层strf，以及作为行为如何影响细胞反应的灵敏晴雨表的多功能反应指标而成为可能的。本研究的总体目标是测试在相同的参考-目标识别范式下，通过在声学目标中选择适当的线索，是否有可能沿着特定的时间或频谱维度诱导快速的STRF塑性。所有实验都遵循相同的行为程序，其中参考信号是宽带，时间和频谱丰富的刺激，这些刺激也在生理实验中用于表征所研究细胞的STRF。而目标则提供识别信号。每个实验都有不同的特征，可以是（AIM I）纯时间的，（AIM II）纯光谱的，或者（AIM III）混合光谱的。

DESCRIPTION (provided by applicant): It is well established that auditory experience can cause significant and continuous reorganization and receptive field plasticity in the primary auditory cortex (AI). The exact form of this plasticity depends on the details of the behavioral context, and of the spectral and temporal cues in the acoustic stimuli. Recent findings indicate further that neuronal responses in AI of awake behaving animals reflect motor, attention, and reward dimensions, rather than simply encoding the acoustic features of the stimuli. This is consistent with findings in other neural systems and supports the hypothesis that auditory cortical cells may undergo rapid, short-term, and 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 reconfiguring of the underlying cortical circuitry to sculpt the most effective receptive field for accomplishing the auditory task. The proposed research explores this hypothesis in combined physiological/behavioral experiments in which spectroternporal receptive fields (STRFs) will be rapidly and comprehensively characterized simultaneous with the animal behavior. The experiments also contrast STRF plasticity in a single cell across different auditory tasks employing various acoustic signals with controlled spectral and temporal features. These unique capabilities are made possible by the development of new ripple stimuli to engage the animal behaviorally while rapidly measuring its cortical STRFs, and versatile response indicators that are sensitive barometers of how behavior affects a cell's responsiveness. The overall goal of the proposed study is to test whether it is possible, under the same reference-target discrimination paradigm, to induce rapid STRF plasticity along specific temporal or spectral dimensions by choosing the appropriate cues in the acoustic target. All experiments follow the same behavioral procedure in which reference signals are broadband, temporally and spectrally rich stimuli that also serve during physiological experiments to characterize the STRF of the cell under study. By contrast, the target provides the discrimination signal. It varies from one experiment to the other with distinctive features that can be (AIM I) purely temporal, (AIM II) purely spectral, or (AIM III) combined spectrotemporal.