Neurophysiology of somatosensory influences on auditory cortical processing

描述（由申请人提供）：在日常感知中，我们无缝地融合来自多种感官（如视觉，听觉，触觉）的信息来辨别和识别我们周围世界的物体。我的长期目标是了解多感觉整合的神经基础及其与知觉的关系。虽然最近的发现告诉我们，振动触觉刺激可以增强人们的听觉，并表明触觉和声音可能在感觉处理流的早期整合，但这种现象的精确解剖电路和生理机制尚不清楚。具体来说，触觉振动刺激对听觉皮层加工的影响是否利用初级和非初级区域的前馈或反馈回路，以及触觉振动输入通过调节听觉神经元兴奋性在多大程度上起作用，而不是引起听觉神经元的直接（加性）兴奋，目前尚不清楚。目前的应用将通过表征振动触觉输入如何影响听觉皮层对声音的鉴别处理来解决这些问题。当清醒的猴子进行听觉辨别时，我将记录下放置在初级和非初级听觉皮层的深度电极的神经元活动。条件将包括单独的听觉刺激，单独的振动刺激和联合刺激。为了帮助定义多感官相互作用的生理学，我将改变听觉刺激的强度以及振动和听觉刺激之间的异步性。分析进入皮层的感觉输入的层流轮廓和时间将有助于确定前馈与反馈电路的影响。分析躯体-听觉相互作用作为刺激操作的功能将有助于确定振动效应是“调性”还是“直接兴奋性”，以及听觉皮层中的振动-听觉相互作用是否遵循公认的多感觉整合原则。我们在Nathan Kline研究所的实验室进行的猴子研究与我们部门（认知神经科学和精神分裂症项目）正在进行的精神分裂症患者的EEC和fMRI研究紧密结合在一起，并与Rockland精神病学中心合作，Rockland精神病学中心是纽约州一家治疗严重和复杂精神疾病的住院机构。特别是，最近的证据表明，精神分裂症患者表现出减少或扭曲的多感觉整合，动物模型为研究这些基本过程的神经元机制提供了最好的方法，而且往往是唯一的方法。因此，拟议的研究直接有助于正在进行的精神分裂症患者多感觉统合功能障碍的研究。

DESCRIPTION (provided by applicant): In everyday perception, we seamlessly fuse information from multiple senses (e.g. sight, hearing, touch) to discern and identify objects in the world around us. My long-term goal is to understand the neural bases of multisensory integration and their relationship to perception. While recent discoveries inform us that vibrotactile stimuli can augment what people hear and indicate that touch and sound may be integrated early in the sensory processing stream, the precise anatomical circuitry and physiological mechanisms of this phenomenon are unknown. Specifically, it is unknown whether the impact of vibrotactile stimuli on auditory cortical processing utilizes feedforward or feedback circuits in primary and non-primary areas and to what extent vibrotactile inputs operate by modulating auditory neuron excitability, as opposed to causing direct (additive) excitation of auditory neurons. The current application will address these questions by characterizing how vibrotactile inputs impact on the discriminative processing of sounds in auditory cortex. I will record neuronal activity from depth electrodes placed in primary and non-primary auditory cortices of awake monkeys while they are performing auditory discriminations. Conditions will include auditory-alone, vibratory-alone and combined stimulation. To help in defining the physiology of multisensory interactions, I will vary the intensity of the auditory stimulus and the asynchrony between vibratory and auditory stimuli. Analysis of the laminar profile and timing of sensory inputs into the cortical layers will help to define effects due to feedforward versus feedback circuitry. Analysis of somato-auditory interactions as a function of stimulus manipulations will help to determine whether vibratory effects are "modulatory" versus "directly excitatory," and also whether vibro- auditory interactions in auditory cortex adhere to recognized principles of multisensory integration. The monkey studies in our laboratory at Nathan Kline Institute are tightly integrated with ongoing EEC and fMRI studies in patients with schizophrenia conducted within our division (Cognitive Neuroscience and Schizophrenia Program), and in cooperation with the Rockland Psychiatric Center, an in-patient New York State facility for severe and complex mental illness. In particular, recent evidence shows that schizophrenic patients exhibit reduced or distorted multisensory integration, and animal models provide the best and often the only methods for research into the neuronal mechanics of these essential processes. The proposed research thus directly contributes to ongoing investigation of multisensory integration dysfunctions in patients with schizophrenia.