FUNCTIONAL ORGANIZATION OF THE INFERIOR COLLICULUS

描述（研究者摘要）：这些研究的主要目标是 来评估来自多个低级听觉核团的输入 塑造哺乳动物丘神经元的反应特性 听觉系统 具体而言，研究人员将：1）确定 投射到丘E1区的细胞，以及投射到丘E1区的细胞。 DNLL和INLL的60 kHz区域是GABA能的， 甘氨酸能的 DNLL和INLL是外侧核的两个核团， 丘系投射到丘的60 kHz区域。 这将 首先，在单个蝙蝠中， 在感兴趣的核中的适当区域进行电生理检查， 记录，然后进行HRP的局灶性注射。 后续 处理将共定位逆行运输的HRP与 针对甘氨酸、GABA和谷氨酸脱羧酶的抗体 (GAD)GABA的合成酶。2)确定单声道和 用单声道记录INLL和DNLL神经元的双耳反应特性 插入扬声器时呈现60 kHz短纯音时的单位活动 进入耳朵。 3)确定抑制剂的功能后果 输入到丘通过构建空间感受野 60 kHz E1神经元的单耳和双耳响应特性， 然后将其与感受野特性的变化进行比较 通过离子电渗法应用荷包牡丹灵和/或士的宁诱导。 因此，他们将评估GABA能和甘氨酸能的不同作用 神经支配在塑造反应特性和空间感受性中的作用 场丘E1神经元，并确定来源或来源， GABA能（或甘氨酸能）影响。最后，通过评估 DNLL和INLL中60 kHz神经元的反应特性和重建 他们的接受领域，他们将获得进一步的见解， 沿着沿着轴突发生的变化，以及较低的核可能是如何 在60 kHz轮廓中对目标施加抑制影响 下丘的神经

DESCRIPTION (Investigator's Abstract): The chief goal of these studies is to evaluate how inputs that originate from multiple lower auditory nuclei shape the response properties of collicular neurons in the mammalian auditory system. Specifically the investigators will: 1) Determine which of the cells that project to the E1 region of the colliculus, and to the 60 kHz regions of the DNLL and INLL, are GABAergic and which are glycinergic. The DNLL and INLL are the two nuclei of the lateral lemniscus that project to the 60 kHz region of the colliculus. This will be accomplished by first, in an individual bat, identifying the appropriate region in the nucleus of interest with electrophysiological recordings, and then making a focal injection of HRP. Subsequent processing will co-localize the retrogradely transported HRP with antibodies directed against glycine, GABA and glutamate decarboxylase (GAD), the synthetic enzyme for GABA. 2) Determine the monaural and binaural response properties of INLL and DNLL neurons by recording single unit activity while presenting 60 kHz tone bursts with speakers inserted into the ears. 3) Determine the functional consequences of the inhibitory inputs to the colliculus by constructing the spatial receptive fields of 60 kHz E1 neurons from their monaural and binaural response properties, which will then be compared to the changes in receptive field properties induced by iontophoretic application of bicuculling and/or strychnine. Thus, they will assess the differential roles of GABAergic and glycinergic innervation in shaping the response properties and spatial receptive fields of collicular E1 neurons, and identify the source or sources, of the GABAergic (or glycinergic) influence. Finally, by evaluating the response properties of 60 kHz neurons in DNLL and INLL and reconstructing their receptive fields, they will obtain further insights into the transformations that occur along the neuraxis, and how lower nuclei may be exerting their inhibitory influence on their targets in the 60 kHz contour of the inferior colliculus.