SYNAPTIC CORRELATES OF VOCAL LEARNING

这个项目将调查声乐学习的细胞基础， 鸣禽 行为学研究已经证实，雄性鸣禽 他们的歌曲从他们的父亲，和调查使用解剖和 电生理学方法已经阐明了大脑回路 学习声乐的必要条件。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 可以做出和测试特定的细胞假设， 突触强度的变化可能会引起发声学习， 鸣禽，但鲜为人知的是，细胞电生理 鸣禽大脑神经元的特性。 拟议的实验将研究神经元在核RA的 鸣禽脑是听觉和运动的重要汇聚部位 这些信息与歌曲学习有关。电压钳 将从体外脑切片中的神经元获得记录，以测试 活动驱动的突触可塑性，类似于长- 术语增强（LTP）或抑郁症（LTD），如在其他研究中所研究的 准备，可以有助于歌曲学习。之前的发现 表明投射到RA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。的 在这些通路中的一个或两个中存在突触可塑性， 通过单独或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。 如果发现突触可塑性的一种形式， 它是否在行为可塑性中发挥作用。虽然 很难设计实验来直接验证这一假设，一些 间接测试是可能的。突触的发育概况 可塑性将被研究，以确定是否在突触的变化， 强度变得不那么明显或更难以诱导， 鸟的歌声不是塑料的。第二，通过改变关键时期， 对于使用荷尔蒙操纵的歌曲学习，应该可以 改变细胞变化的关键时期。 这些研究将是第一批在脊椎动物系统中进行检查的研究， 突触强度的变化和学习复合体之间的联系 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.