Spectro-temporal Plasticity in Primary Auditory Cortex

描述（由申请人提供）：众所周知，听觉体验可以引起初级听觉皮层（AI）中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背景的细节，以及声音刺激中的频谱和时间线索。最近的研究结果进一步表明，清醒行为动物AI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，并支持这一假设，即听觉皮层细胞可能会经历快速，短期的，和上下文相关的变化，其感受野特性时，动物从事不同的听觉行为任务。这种可塑性可能涉及对底层皮层回路的选择性功能重组，以塑造完成听觉任务的最有效感受野。拟议的研究探讨了这一假设在相结合的生理/行为实验中，spectroternporal感受野（STRFs）将迅速和全面的特点，同时与动物的行为。实验还对比STRF可塑性在一个单一的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。这些独特的能力是通过开发新的涟漪刺激来吸引动物的行为，同时快速测量其皮质SRFs，以及多功能反应指标来实现的，这些指标是行为如何影响细胞反应性的敏感晴雨表。该研究的总体目标是测试是否有可能，在相同的参考目标的歧视范例，诱导快速STRF可塑性沿着特定的时间或频谱维度，通过选择适当的线索在声目标。所有实验都遵循相同的行为程序，其中参考信号是宽带的、时间上和频谱上丰富的刺激，这些刺激在生理实验期间也用于表征所研究的细胞的STRF。相比之下，目标提供辨别信号。它从一个实验到另一个实验都有不同的特点，可以是（AIM I）纯时间，（AIM II）纯光谱，或（AIM III）组合spectrotemporal。

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.