SYNAPTIC CORRELATES OF VOCAL LEARNING

这个项目将研究发声学习的细胞基础。 鸣禽。行为研究已经证实，雄性鸣禽会学习 他们来自父亲的歌曲，以及使用解剖学和 电生理学方法已经阐明了大脑回路。 对于声乐学习来说是必要的。在各种系统中的工作表明 突触可塑性在学习中的关键作用。现在是时候了 可能做出并测试特定的细胞假说 突触强度的变化可能会导致发声学习 鸣禽，但对细胞电生理知之甚少 鸣禽大脑中神经元的特性。 拟议的实验将研究大鼠视网膜核中的神经元。 鸣禽大脑--听觉和运动的重要交汇点 与歌曲学习有关的信息。电压钳位 录音将从体外脑片中的神经元中获得，以进行测试 该假说认为，活动驱动的突触可塑性，类似于长- 术语增强(LTP)或抑郁(LTD) 准备，可以为歌曲学习做出贡献。之前的研究结果 提示投射到类风湿关节炎神经元的听觉和运动通路使用 突触后神经递质受体的不同组合。这个 在这两条通路中的一条或两条中存在突触可塑性 通过单独和组合应用各种类型的 在其他表现出可塑性的系统中有效的刺激。 如果发现了一种形式的突触可塑性，就有必要进行测试 它是否会在行为可塑性中发挥作用。尽管它是 很难设计实验来直接检验这一假设，有许多 间接测试是可能的。突触的发育概况 可塑性将被调查以确定突触的变化 在以下情况下，力量变得不那么明显或更难诱导 鸟儿的歌声不是塑料的。第二，通过转移关键期 对于使用荷尔蒙操作的歌曲学习来说，应该有可能 改变细胞变化的关键期。 这些研究将是第一批在脊椎动物系统中检查的研究之一， 突触强度的变化与复合体学习之间的联系 行为。

This project will investigate the cellular basis of vocal learning in songbirds. Behavioral studies have established that male songbirds learn their songs from their fathers, and investigations using anatomical and electrophysiological approaches have elucidated the brain circuitry necessary for vocal learning. Work in a variety of systems has pointed toward a critical role for synaptic plasticity in learning. It is now possible to make and test specific cellular hypotheses concerning how changes in synaptic strength could give rise to vocal learning in songbirds, but little is known of the cellular electrophysiological properties of the neurons in the songbird brain. The proposed experiments will investigate neurons in nucleus RA of the songbird brain, an important site of convergence of auditory and motor information which has been implicated in song learning. Voltage-clamp recordings will be obtained from neurons in in vitro brain slices to test the hypothesis that activity-driven synaptic plasticity, resembling long- term potentiation (LTP) or depression (LTD) as studied in other preparations, could contribute to song learning. Previous findings indicate that the auditory and motor pathways projecting to RA neurons use different combinations of postsynaptic neurotransmitter receptors. The existence of synaptic plasticity in one or both of these pathways will be tested by applying, individually and in combination, various types of stimuli that are effective in other systems exhibiting plasticity. If a form of synaptic plasticity is found, it will be necessary to test whether it might play a role in behavioral plasticity. Although it is difficult to design experiments to test this hypothesis directly, a number of indirect tests are possible. The developmental profile of synaptic plasticity will be investigated to determine whether changes in synaptic strength become less pronounced or more difficult to induce at times when the bird's song is not plastic. Secondly, by shifting the critical period for song learning using hormonal manipulations, it should be possible to shift the critical periods for cellular changes. These studies will be among the first to examine, in a vertebrate system, the link between changes in synaptic strength and learning of a complex behavior.