NEURAL CHANGES ASSOCIATED W/CRITICAL LEARNING PERIODS

本提案的目的是（1）确定细胞的变化， 发展中的鸟类大脑是“关键”或“敏感”时期的基础 （2）确定这些变化是如何影响的 通过学习类似于歌曲的发声。 大多数鸟学唱歌 记忆一个合适的歌曲模型（感官学习），然后使用 听觉反馈来模仿该模型（感觉运动学习）。 这些 声音学习的两个阶段通常仅限于特定的物种 发展时期被认为是与 与歌曲相关的大脑区域。 在斑胸草雀中， 例如，感觉和感觉运动学习重叠， 在数量、大小和与歌曲相关的神经元的连通性上。 的 提出的第一项研究将采用比较神经解剖学方法， 更好地定义神经变化和感觉或 感觉运动学习 声带解剖的发育变化 细胞核将在沼泽麻雀中测量，这是一种两个 声乐学习的各个阶段在时间上是分开的。 下一篇：Neural 对于记住声音模型可能必要的改变将是 鉴定 隔音将用于延长关键的 斑胸草雀感官学习的时期。 然后它将 确定了这种操作如何影响神经变化的时间 在发展中的歌区。 最后，确定歌曲学习如何 影响了鸣唱神经核团的组织， 与歌曲复杂性的个体差异有关。 同时，听觉体验影响大脑发育的能力， 在感觉或感觉运动过程中保留或增加神经元 学习将被评估。 存在关键的学习期， 语言习得、社会依恋和 印记 该提案的长期目标是了解神经 这些独特易感性时期的潜在机制以及 确定如何通过依赖经验的 发育中的神经系统的变化。

The aims of this proposal are to (1) identify cellular changes in the developing avian brain that underlie "critical" or "sensitive" periods for vocal learning and, (2) to determine how such changes are influenced by the learning of song-like vocalizations. Most birds learn song memorizing a suitable song model (sensory learning) and then using auditory feedback to mimic that model (sensorimotor learning). These two phases of vocal learning are often restricted to species-specific developmental period believed to coincide with pivotal changes in the organization of song-related brain regions. In zebra finches, for instance, sensory and sensorimotor learning overlap with drastic changes in the number, size, and connectivity of song-related neurons. The first study proposed will employ a comparative neuroanatomical approach to define better the relationship between neural change and sensory or sensorimotor learning. Developmental changes in the anatomy of vocal nuclei will be measured in swamp sparrows, a species in which the two phases of vocal learning are well separated in time. Next, neural changes that may be necessary for memorizing a vocal model will be identified. Acoustic isolation will be used to extend the critical period for sensory learning in zebra finches. It will then be determined how this manipulation influences the timing of neural changes in developing song regions. Finally, to determine how song learning influences the organization of song nuclei, neuroanatomical measurements will be correlated with individual differences in song complexity. Also, the ability of auditory experiences to influence the growth, retention, or addition of neurons during sensory or sensorimotor learning will be assessed. Critical learning periods exist for phenomenon as diverse as language acquisition, social attachment and imprinting. The proposal's long-term goal is to understand the neural mechanisms underlying these periods of unique susceptibility and to determine how information may be stored through experience-dependent modifications of the developing nervous system.