Contextual plasticity in spatial auditory maps

描述（由申请人提供）：当前的项目探索空间听觉感知的动态过程。具体来说，它研究了听觉空间的表征如何适应由先前的刺激和听者的行为任务所定义的听觉环境。提出了一系列的行为实验和计算模型研究。第一个被验证的假设是，情境可塑性不仅受到自下而上因素的影响，比如刺激的空间分布，还受到自上而下因素的影响，比如听者对预期目标位置的注意力和对干扰物位置的注意力。这将通过比较听者在执行需要特定空间注意力分配的任务时观察到的可塑性和在不需要集中注意力时观察到的可塑性来测试。第二种假说认为情境可塑性受刺激的时空分布的影响。这将通过测量在不同空间和时间分布的干扰物和目标刺激的听觉场景中观察到的可塑性来测试。第三种假设是，语境可塑性的解剖位点位于听觉通路的中心水平，在那里，潜在的双耳线索被整合到空间感知中。这将通过评估由耳间时间线索引起的语境可塑性在多大程度上概括为听觉定位的耳间强度线索，反之亦然来检验。这些实验的结果将在听觉空间感知层次模型的背景下进行评估。先前的研究发现，空间听觉表征的短期可塑性可以通过持续呈现恒定的刺激或通过听众调整听觉感知的视觉反馈来诱导。除此之外，空间听觉感知被认为是静态的。本项目中所探索的情境可塑性的存在是很重要的，因为它表明听觉空间表征是动态的，它会随着听者的任务和听觉场景而不断变化。了解听力正常的听者如何适应听觉环境是至关重要的，例如，因为听觉外围受损的听者的中央听觉加工可能发生类似的可塑性变化。设计能够预测和适应这种神经可塑性的假肢装置可能会显著提高这些装置的性能。这项研究将主要在斯洛伐克科希策技术大学与Norbert Kopco合作进行，作为NIH拨款#5R01 DC005778-03的延伸。

DESCRIPTION (provided by applicant): The current project explores dynamic processes in spatial auditory perception. Specifically, it studies how representations of auditory space adapt to the auditory context defined by the preceding stimulation and by the listener's behavioral task. A series of behavioral experiments and computational modeling studies is proposed. The first tested hypothesis is that the contextual plasticity is influenced not only by the bottom-up factors, like the spatial distribution of the stimuli, but also by the top-down factors, for example, by the listener's concentration on the expected target locations and away from the distractor locations. This will be tested by comparing the plasticity observed when the listener is performing a task that requires specific distribution of spatial attention to plasticity observed when attention does not need to be focused. The second hypothesis is that the contextual plasticity is influenced by the spatial and temporal distribution of the stimuli. This will be tested by measuring plasticity observed in auditory scenes with various spatial and temporal distributions of distractor and target stimuli. The third hypothesis is that the anatomical locus of the contextual plasticity is at a central level of the auditory pathway where the underlying binaural cues are integrated into spatial percepts. This will be tested by evaluating the extend to which contextual plasticity induced by interaural temporal cues generalizes to interaural intensity cues for auditory localization, and vice versa. The results of these experiments will be evaluated in the context of the hierarchical model of auditory spatial perception proposed in the parent grant. Previous studies found that short-term plasticity in spatial auditory representations can be induced by sustained presentation of constant stimuli or by visual feedback to which the listeners align the auditory percepts. Other than that, spatial auditory perception was thought of as being static. The existence of contextual plasticity explored in this project is important because it suggests that auditory spatial representation is dynamic and that it changes continuously depending on the listener's task and on the auditory scene. Understanding how normal-hearing listeners adapt to the auditory context is critical, e.g., because similar plastic changes might take place in the central auditory processing of listeners with impaired auditory periphery. And designing prosthetic devices that predict and adapt to this neural plasticity might significantly improve the performance of such devices. This research will be done primarily in Slovakia at the Technical University of Kosice in collaboration with Norbert Kopco, as an extension of NIH grant #5R01 DC005778-03.