Spectro-temporal Plasticity in Primary Auditory Cortex

描述(由申请人提供)：众所周知，听觉体验可以导致初级听觉皮质(AI)显着和持续的重组和接受场可塑性。这种可塑性的确切形式取决于行为背景的细节，以及声音刺激中的光谱和时间线索的细节。最近的发现进一步表明，清醒行为动物人工智能中的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。这与在其他神经系统中的发现是一致的，并支持这样的假设，即当动物从事不同的听觉行为任务时，听觉皮质细胞可能会经历其感受野特性的快速、短期和上下文相关的变化。这种可塑性很可能涉及到对底层皮质回路的选择性功能重新配置，以塑造完成听觉任务的最有效的接受场。这项拟议的研究在生理/行为联合实验中探索了这一假设，在这些实验中，频谱临时感受野(STRF)将与动物行为同时快速和全面地表征。这些实验还比较了单个细胞在不同听觉任务中的STRF可塑性，使用了具有受控频谱和时间特征的各种声音信号。这些独特的能力之所以成为可能，是因为开发了新的涟漪刺激来参与动物的行为，同时快速测量其皮质STRF，以及多功能反应指标，这些指标是行为如何影响细胞反应的敏感晴雨表。这项拟议研究的总体目标是测试在相同的参考目标辨别范式下，是否有可能通过在声学目标中选择适当的线索来在特定的时间或频谱维度上诱导快速的STRF可塑性。所有实验都遵循相同的行为程序，其中参考信号是宽带、时间和光谱丰富的刺激，在生理实验期间也用于表征被研究细胞的STRF。相比之下，目标提供了歧视信号。从一个实验到另一个实验，它具有不同的特征，可以是(AIM I)纯时间、(AIM II)纯光谱或(AIM III)组合的光谱时间。

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.