Information processing in sensory systems

描述（由申请人提供）：该提案的主要目标是了解听觉系统中早期丘脑皮层处理阶段的功能组织。这涉及更好地理解连接下丘（1C），内侧膝状体（MGB），第一和第二听觉皮层（Al和All）的各种通路的功能。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具有1C至MGB、MGB至AI/AII、Al至MGB和Al至All通路的完整性。我们将通过光刺激或最小电刺激释放谷氨酸来测试每个通路的功能。特别是，我们将尝试将每个路径识别为驱动程序（即，信息的主要传输者）或调制器，并通过识别驱动程序，我们希望构建一个功能层次的信息流。这将使我们能够测试的假设，即在系统中的信息流的主要途径是从中央1C（ICc）到腹侧部分的MGB（MGBV）到Al背侧MGB（MGBd，我们建议是一个更高级别的丘脑中继）到所有。这与传统的观点形成对比：一种是ICc到MGBv到Al和1C（IC）到MGBd到All的壳区域的平行路径;另一种是从ICc到MGBv到Al到All的路径。这些功能组织的假设并不相互排斥，可能存在组合。尽管如此，在我们开始理解这些通路中的病理如何导致听力问题之前，我们必须更好地理解听觉信息是如何通过皮层处理的前几个阶段传递的。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，这是我们必须更好地了解这些网络。

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.