PARALLEL AUDITORY PATHWAYS IN THE BRAIN STEM

拟议研究的总主题是了解 下丘（IC）的行为方面的操作 那个禽兽 这里选择的行为是蝙蝠的回声定位。 的 实验策略是检查感觉加工， 行为相关的刺激在IC和检查的相互作用 带马达系统的IC 提出了三个具体目标。 第一 目的是检验这一假设，即兴奋性和 在时间上彼此偏移的抑制性输入产生调谐， 时变的声音。 三种重要的调优 动物的行为将被考虑：调谐到声音持续时间，调谐 频率调制扫描和调谐到重复频率的速率 调制 电生理学研究，包括全细胞贴片- 钳夹观察，将用于检查兴奋性序列 和由这些声音引起的抑制性突触事件。 的 第二个目的是检验这一假设，即IC中的加工是 受运动活动的影响。 例如，来自实体的投入是否 黑质调节感觉处理的IC？ 在这些研究中，方法 将用于刺激或消除来自 黑质对IC的反应，同时记录IC神经元的反应 声音。 第三个目的是确定IC是否发送相同的 当它发送到电机系统时， 丘脑皮质系统 这些研究将利用双逆行 标记技术来识别IC神经元是否投射到两个 不同的目标 例如，在IC项目中做同样的神经元 到丘脑和脑桥灰质 建议的调查结果 研究将对理解潜在的机制具有重要意义 神经系统选择生物学上重要声音的能力， 来理解选择过程是如何转变成 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.