Neurophysiology and Anatomy of Multisensory Processing

描述（由申请人提供）：多感觉整合开始于初级听觉皮层（A1）或之前的水平，并在更高的阶段建立。在A1的效果似乎主要是一个非听觉的“调制”的强度“驾驶”的听觉输入，而在更高的地区，它可能越来越多地反映了一个更高阶的“整合”的听觉和非听觉信息。在A1中，听觉/非听觉相互作用使用神经元振荡作为听觉反应放大的工具，而在更高的阶段，相互作用还需要经典的兴奋性会聚。贯穿始终，输入的显著性（自下而上）和自上而下的注意控制的影响被认为是至关重要的。这些元素--神经元振荡、调节驱动相互作用、自上而下的控制和底层的解剖回路--对大脑运作来说是无处不在和至关重要的。在多感觉相互作用的背景下调查它们提供了对关键输入的独特明确的控制，因为它们来自不同的受体表面。我们的主要目标是研究听觉系统各层次的多感觉交互作用，作为大脑整合操作的一般模型。我们结合联合收割机解剖分析与电生理方法索引层配置文件的突触活动和伴随的动作电位，区分“驾驶”听觉输入和非听觉“调制”输入所产生的各种皮层和皮层下的来源，并确定这些输入类型如何相互作用的生理过程中注意的歧视。具体目标1是表征跨加工水平的多感觉表征的机制和进化。具体目标2是确定如何跨通道线索，预测声音的时间和位置，帮助听觉处理。具体目标3是表征听觉皮层中驱动和调制回路的精细结构，强调目标1和2下检查的过程的解剖学相关性。对神经元振荡在驱动输入处理中的关键工具功能、通过调制输入对其进行操纵、刺激显著性和注意力的影响以及潜在电路的理解的提高，将增强对正常听力的机械理解，以及对导致许多病理状况的听力潜在中断的理解。

DESCRIPTION (provided by applicant): Multisensory Integration begins at or before the level of primary auditory cortex (A1) and builds over higher stages. In A1 the effect seems to be mainly a non-auditory "modulation" of the strength of "driving" auditory inputs, while in higher areas it may increasingly reflect a higher order "integration" of auditory and non-auditory information. In A1, auditory/non-auditory interactions use neuronal oscillations as instruments of auditory response amplification, while in higher stages, interactions also entail classic excitatory convergence. Throughout, the impact of inputs' salience (bottom-up), and that of top-down attentional control are believed to crucial. These elements - neuronal oscillations, modulatory-driving interactions, top-down control, and the underlying anatomic circuits - are ubiquitous and crucial to brain operation. Investigating them in the context of multisensory interactions affords a unique unambiguous control over the key inputs since they arise from different receptor surfaces. Our BROAD GOAL is to investigate multisensory interaction across levels of the auditory system as a general model for integrative operations in the brain. We combine anatomical analyses with electrophysiological methods indexing laminar profiles of synaptic activity and concomitant action potentials to differentiate "driving" auditory inputs and non-auditory "modulatory" inputs arising from various cortical and subcortical sources, and to determine how these input types interact physiologically during attentive discrimination. SPECIFIC AIM 1 is to characterize the mechanisms and evolution of multisensory representation across processing levels. SPECIFIC AIM 2 is to determine how cross modal cues that predict sound timing and location help auditory processing. SPECIFIC AIM 3 is to characterize the fine structure of driving and modulatory circuits in auditory cortex, emphasizing anatomical correlates of processes examined under Aims 1 and 2. Improved understanding of the critical instrumental functions of neuronal oscillations in processing of driving inputs, their manipulation by modulatory inputs, influences of stimulus salience and attention, and the underlying circuitry, will enhance the mechanistic understanding of normal hearing, as well as those underlying disruptions of hearing that contribute to a number of pathological conditions.