FUNCTIONAL ORGANIZATION OF THE INFERIOR COLLICULUS

建议的研究将评估神经编码和表示 在“60 kHz”等频板内的双耳和空间信息 胡子蝙蝠的下丘(IC)。在最近的研究中，我们有 发现蝙蝠IC的中央核团有3个功能分区 在生理和建筑标准上都有区别。这个 最大的是背后部(DPD)，所有神经元都有 几乎相同的最佳频率。 DPD是一种体型大大扩大，但基本上是标准的哺乳动物 等频轮廓，或板层。因为哺乳动物的IC是由 从连续堆叠的板层，DPD是神经元的基本单位 建筑以高度放大的形式呈现。我打算利用这一点 自适应以评估：1)双耳信息如何通过以下方式进行编码 DPD神经元。将特别注意确定是否 神经元可以编码耳间相位或时间差。2)神经元如何 具有共同的双耳特性被组织在DPD内。3)什么 耳廓对60 kHz声音方向性特征的影响 到达耳蜗处。4)神经过程如何与耳廓效应相互作用 以塑造DPD神经元的空间选择性。5)有什么关联 存在于具有共同双耳特征的DPD神经元和 起源于低位听觉中枢的投射系统的特异性 在脑干里。

The proposed studies will evaluate the neural encoding and representation of binaural and spatial information within the "60 kHz" isofrequency lamina of the mustache bat's inferior colliculus (IC). In recent studies we have found that the central nucleus of the bat's IC has 3 functional divisions distingusished on both physiological and architectural criteria. The largest is the dorsoposterior division (DPD) in which all neurons have virtually the same best frequency. The DPD is a greatly enlarged, but fundamentally standard mammalian isofrequency contour, or lamina. Since the mammalian IC is constructed from serially stacked laminae, the DPD is a basic unit of neuronal architecture present in highly magnified form. I intend to exploit this adaptation in order to evaluate: 1) How binaural information is encoded by DPD neurons. Particular attention will be given to determining whether neurons can encode interaural phase or time disparities. 2) How neurons having common binaural properties are organized within the DPD. 3) What influence the pinnae have upon the directional features of 60 kHz sounds reaching the cochlea. 4) How neural processes interact with pinna effects to shape the spatial selectivity of DPD neurons. 5) What correlations exist between DPD neurons having common binaural characteristics and the specificity of projection systems originating from lower auditory centers in the brainstem.