Information processing in sensory systems

描述（由申请人提供）：该提案的总体目标是了解听觉系统处理的早期丘脑皮质阶段的功能组织。这涉及到对连接下丘（1C）、内侧膝状体（MGB）和第一和第二听觉皮层（Al和All）的各种通路的更好的功能理解。我们将使用小鼠大脑的体外切片制备，其中不同的切片配置将使1C到MGB、MGB到AI/AII、Al到MGB和Al到All通路完整。我们将通过光刺激或最小电刺激来释放谷氨酸来测试每种途径的功能。特别是，我们将尝试将每个路径识别为驱动器（即信息的主要传输器）或调制器，并且通过识别驱动器，我们希望构建信息流的功能层次结构。这将使我们能够测试这样一个假设，即系统中信息流的主要途径是从中央1C （ICc）到MGB的腹侧部分（MGBv）到Al到MGB的背侧（MGBd，我们认为这是一个高阶的丘脑中继）到All。这与传统的观点形成了对比：一种是ICc到MGBv到Al的平行路径和1C （ic）到MGBd到All的壳区；另一条是从ICc到MGBv再到人工智能到全民的道路。这些功能组织的假设不是相互排斥的，可能存在组合。尽管如此，我们必须更好地了解听觉信息是如何通过皮层处理的前几个阶段传递的，然后才能开始理解这些途径中的病理是如何导致听力问题的。也就是说，认知听觉功能，如词汇语义处理、语音信息提取、选择性注意和物体识别几乎肯定是由听觉皮层网络服务的，而我们必须更好地理解这些网络。

DESCRIPTION (provided by applicant): The broad goal of the proposal is to understand the functional organization of the early thalamocortical stages of processing in the auditory system. This involves a better functional understanding of the various pathways connecting the inferior colliculus (1C), medial geniculate body (MGB), and first and second auditory cortices (Al and All). We will use an in vitro slice preparation of the mouse brain in which different slice configurations will have the 1C to MGB, MGB to AI/AII, Al to MGB, and Al to All pathways intact. We will use uncaging of glutamate by photostimulation or minimal electrical stimulation to test the function of each of the pathways. In particular, we shall attempt to identify each pathway as a driver (i.e., main conveyer of information) or modulator, and by identifying the drivers, we hope to construct a functional hierarchy of information flow. This will allow us to test the hypothesis that a main route of information flow in the system is from the central 1C (ICc) to the ventral portion of MGB (MGBv) to Al to the dorsal MGB (MGBd, which we suggest is a higher order thalamic relay) to All. This is contrasted to conventional views: one is of parallel paths of ICc to MGBv to Al and shell region of 1C (ICs) to MGBd to All; another is a path from ICc to MGBv to Al to All. These hypotheses of functional organization are not mutually exclusive, and combinations may exist. Nonetheless, we must obtain a better understanding of how auditory information is routed through the first few stages of cortical processing before we can begin to understand how pathology in these pathways can lead to problems in hearing. That is, cognitive auditory functions, such as lexical-semantic processing, phonological information extraction, selective attention and object recognition are almost certainly subserved by auditory cortical networks, and it is these networks that we must better understand.