INTEGRATION OF INPUTS IN THE INFERIOR COLLICULUS

下丘输入的整合

• 批准号: 2649794
• 负责人: KEVIN A DAVIS
• 金额: $ 5.61万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2649794
• 关键词: auditory nuclei; auditory pathways; bicuculline; brain metabolism; cats; decerebration; drug metabolism; gamma aminobutyrate; glycine; inferior colliculus; lidocaine; nerve threshold; neural information processing; neuropharmacology

DESCRIPTION: The proposed studies seek to establish the functional circuitry underlying the upper threshold units found in the mammalian inferior colliculu Most auditory brainstem units increase or maintain their response as stimulus intensities are raised above threshold levels. Upper threshold units are characterized by a response decrease or elimination as stimulus intensity is raised 30 to 40 dB above best frequency threshold. Upper threshold units are common in the inferior colliculus and the dorsal cochlear nucleus, but less common elsewhere in the auditory brainstem. The first aim will test whether t dorsal cochlear nucleus is the source of the upper threshold response properti seen in the inferior colliculus. Besides having similar unit properties, the dorsal cochlear nucleus projects to the contralateral colliculus via its main output tract: the dorsal acoustic striae. After isolating and characterizing units in the inferior colliculus, lidocaine will be applied to dorsal acoustic striae to reversibly block the input from the dorsal cochlear nucleus. Reversible alteration or loss of upper threshold properties in collicular unit following dorsal acoustic striae blockage would implicate the dorsal cochlear nucleus as a source of this response pattern. To further implicate dorsal cochlear nucleus in the activity of recorded collicular units, some experiment will include stimulation of somatosensory inputs to the dorsal cochlear nucleu while monitoring collicular response patterns. The second aim will test the most obvious alternate hypothesis: that the upper threshold inhibition pattern is built up within the inferior colliculus on the basis of local interactions excitatory and inhibitory inputs. Under this aim, recorded unit properties within the colliculus under normal conditions will be compared with properties of the same units after local application of pharmacological blockers (bicuculline or strychnine) of the inhibitory neurotransmitters GABA or glycin Studies will be carried out in a decerebrate preparation to limit possible anesthetic effects that could alter dorsal cochlear nucleus outputs.

描述：拟议的研究试图建立功能 在哺乳动物中发现的上阈值单元的电路 较低的丘脑大多数听觉脑干单元增加或保持其 刺激强度的响应高于阈值水平。 上 阈值单位的特征是响应减少或消除为 刺激强度高于最佳频率阈值30至40 dB。 上阈值单元在下丘和背侧很常见 耳蜗核，但在听觉脑干中其他地方不太常见。 这 第一个目标将测试T背部耳蜗核是否是 在下丘中看到的上阈值响应属性。 除了 具有相似的单位特性，背部耳蜗核将 对侧丘丘通过其主要输出区域：背面声学 斯特里亚。 在隔离和表征下方的单位之后 Colliculus，Lidocaine将被应用于背声质。 可逆地阻止从背部耳蜗核的输入。 可逆 胶体单元中上阈值的变化或丧失 遵循背面的声音障碍物将暗示背侧 耳蜗核是该反应模式的来源。 进一步暗示 在记录的胶原单元活性中的背部耳蜗核，有些 实验将包括刺激背面的体感输入 在监测碰撞反应模式的同时，耳蜗核。 第二个 AIM将检验最明显的替代假设：上层 阈值抑制模式是在下山脉内建立的 局部相互作用兴奋和抑制投入的基础。 在下面 此目的是正常的山脉内记录的单位特性 将条件与本地后同一单元的属性进行比较 药理学阻滞剂（双瓜氨酸或士苯胺）的应用 抑制性神经递质GABA或甘氨酸研究将在A中进行 尿液准备工作以限制可能的麻醉作用 改变背部耳蜗核输出。