FUNCTIONAL ORGANIZATION OF INFERIOR COLLICULUS

下丘的功能组织

• 批准号: 6516051
• 负责人: GEORGE D POLLAK
• 金额: $ 35.7万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-07-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6516051
• 关键词: Chiroptera; auditory pathways; bicuculline; binaural hearing; inferior colliculus; muscimol; neurons; neuropharmacology; sound frequency

DESCRIPTION: (Adapted From The Applicant's Abstract.) The chief goal of these studies is to evaluate how the largely GABAergic inhibitory outputs of the dorsal nuclei of the lateral lemniscus (DNLLs) shape the monaural and binaural properties of EI neurons in the DNLL and inferior colliculus (ICc). The system to be used for these studies is the enlarged 60 kHz isofrequency contour of the mustache bat's DNLL and ICc. Pharmacological studies conducted during the previous grant period prompted a number of hypotheses about the roles that the ipsi- and contralateral DNLLs play in shaping the binaural properties and azimuthal receptive fields of ICc neurons. The goals of the proposed studies are to test those hypotheses with reversible inactivation of either the ipsi- or contralateral DNLLs while monitoring the response properties of EI cells in the opposite DNLL or ICc. Four sets of experiments are proposed to test these hypotheses: 1) The role of the commissure of Probst will be evaluated by recording the monaural and binaural properties of 60 kHz DNLL neurons and then assessing the same properties after the DNLL on the opposite side has been reversibly inactivated by the iontophoretic application of muscimol, an agonist for GABAa receptors. After recovery from inactivation, bicuculline will be iontophoretically applied to the neuron under study and the same properties will be determined again. 2) The same procedures will be used to evaluate the roles of the contra- and ipsilateral DNLLs on the monaural and binaural response properties of 60 kHz EI neurons in the ICc. The influence of the contra- and ipsilateral DNLLs will be assessed in separate experiments. 3) The effects of an initial sound on the binaural properties evoked by a second sound that follows shortly thereafter will be evaluated in ICc neurons. Initially the ICc cell's normal binaural properties with a single sound presented over a wide range of IIDs will be established. Subsequently, two successive binaural tone bursts will be presented. The IID of the first stimulus will be fixed and will favor the inhibitory ear while the second stimulus will be presented with a wide range of IIDs that would be produced when sounds emanate from different regions of space. The procedure will then be repeated but the first stimulus will have a fixed IID that favors the excitatory ear. The hypothesis predicts that the binaural properties evoked by the second signals: a) will be changed, and thus the response evoked by that sound will be different from those evoked by a single sound; b) will be different when the initial signal favors the ipsi ear from the properties obtained when the initial signal favors the contra ear; and c) will be due, in part, to the inhibition of either the ipsi- or contralateral DNLL that was evoked by the first signal. 4) To test the hypothesis that inhibition at the DNLL evoked by the first signal is responsible for the changes in binaural properties at the ICc evoked by a second signal, the same properties in ICc neurons will be assessed when either the ipsi- or contralateral DNLLs are inactivated by the iontophoretic application of muscimol.

描述：（改编自申请人的摘要。）主要目标 这些研究的目的是评估如何在很大程度上抑制GABA能 外侧丘系背核输出的形态 DNLL中EI神经元的单耳和双耳特性， 下丘（ICc）。 用于这些研究的系统是 放大的60 kHz等幅曲线显示了胡子蝠的DNLL， 国际刑事法院c。 上一次资助期间进行的药理学研究 这一时期引发了许多关于ipsi角色的假设- 和对侧DNLL在塑造双耳特性中起作用， ICc神经元的方位感受野。 拟议的目标 研究是为了验证这些假设与可逆失活的 同侧或对侧DNLL，同时监测 EI细胞在相反的DNLL或ICc中的响应特性。 四套 提出了实验来验证这些假设：1）作用 将通过记录Probst连合的 60 kHz DNLL神经元的单耳和双耳特性，然后 在对侧DNLL之后评估相同的属性 已经被离子电渗疗法应用可逆地灭活 蝇蕈醇是GABA α受体的激动剂。 恢复后 灭活，荷包牡丹碱将被离子电渗应用于 研究中的神经元和相同的属性将被再次确定。 2)将使用相同的程序来评估 对侧和同侧DNLL对单耳和双耳反应的影响 ICc中60 kHz EI神经元的特性。 的影响 对侧和同侧DNLL将在单独的实验中评估。 3)初始声音对双耳诱发特性的影响 随后不久的第二个声音将被评估 在ICc神经元中。 最初，ICc细胞的正常双耳特性 一个单一的声音在广泛的IID将是 确立了习 随后，两个连续的双耳纯音将被 提出了 第一个刺激的IID将是固定的， 当第二个刺激出现时， 当声音发出时， 来自不同的空间区域。然后将重复该过程， 第一个刺激将有一个固定的IID， 耳朵该假设预测， 第二信号：a）将被改变，因此引起的响应 由该声音引起的声音将不同于由单个声音引起的声音; B） 当初始信号有利于ipsi耳朵时会有所不同 从初始信号有利于对立面时获得的属性， 耳;和c）将由于，部分，以抑制或ipsi- 或由第一信号诱发的对侧DNLL。 4)到 测试的假设，抑制在DNLL诱发的 第一信号负责双耳特性的变化， 由第二信号诱发的ICc，ICc中的相同特性 当同侧或对侧神经元 DNLL通过离子电渗应用 蝇蕈醇