PARALLEL AUDITORY PATHWAYS IN THE BRAIN STEM

拟议研究的总主题是理解 关于下丘(IC)行为的手术 这只动物。这里选择的行为是蝙蝠的回声定位。这个 实验策略是检查感觉加工过程 IC中与行为相关的刺激，并检查 带有马达系统的集成电路。提出了三个具体目标。第一 目的是检验这样一种假设，即兴奋性和 抑制性输入，在时间上相互抵消，产生调谐 时变的声音。这三种调优在 动物的行为将被考虑：调整到声音持续时间，调整 到调频扫频和调谐到重复频率 调制。电生理研究，包括全细胞贴片- 钳位观察，将用来检查兴奋性序列 以及由这些声音引发的抑制性突触事件。这个 第二个目标是检验IC中的处理是 受运动活动的影响。例如，来自实体的输入 黑质在中枢神经系统调节感觉加工？在这些研究中，方法 将用于刺激或停用来自 黑质对IC神经元反应的记录 听起来。第三个目标是确定IC是否发送相同的 类信息发送到电机系统，因为它将 丘脑皮质系统。这些研究将利用双重逆行 识别IC神经元是否投射到两个神经元的标记技术 不同的目标。例如，在IC项目中做同样的神经元 丘脑和桥脑灰质？建议的研究结果 研究将对理解潜在的机制具有重要意义。 神经系统选择具有重要生物学意义的声音和 为了了解遴选过程是如何转变为 行为。

The general theme of the proposed research is to understand the operations of the inferior colliculus (IC) in terms of the behavior of the animal. The behavior chosen here is echolocation in the bat. The experimental strategies are to examine sensory processing of behaviorally relevant stimuli in the IC and to examine interactions of the IC with motor systems. Three specific aims are proposed. The first aim is to test the hypothesis that interactions of excitatory and inhibitory inputs, offset from one another in time, produce tuning to time varying sounds. Three kinds of tuning that are important in the animal's behavior will be considered: Tuning to sound duration, tuning to frequency modulated sweeps and tuning to rate of repetitive frequency modulations. Electrophysiological studies, including whole-cell patch- clamp observations, will be used to examine the sequence of excitatory and inhibitory synaptic events that are elicited by these sounds. The second aim is to test the hypothesis that processing in the IC is influenced by motor activities. For example, does input from substantia nigra modulate sensory processing in the IC? In these studies, methods will be used to stimulate or to inactivate motor-related input from the substantia nigra to the IC while recording the response of IC neurons to sound. The third aim is to determine whether the IC sends the same class of information to the motor system as it sends to the thalamocortical system. These studies will utilize double retrograde marking techniques to identify whether or not IC neurons project to two different targets. For example, do the same neurons in the IC project to the thalamus and to the pontine grey? The findings of the proposed research will be significant for understanding the mechanisms underlying the nervous system's ability to select biologically important sounds and for understanding how the selection process is transformed into behavior.