NEURAL CHANGES ASSOCIATED W/CRITICAL LEARNING PERIODS

这项建议的目的是(1)确定细胞在 处于“关键”或“敏感”时期的发育中的禽脑 用于声乐学习，以及(2)确定这些变化是如何影响的 通过学习像歌曲一样的发声。大多数鸟儿学会唱歌 记忆合适的歌曲模型(感官学习)，然后使用 模仿该模型的听觉反馈(感觉运动学习)。这些 发声学习的两个阶段通常局限于特定物种。 发育期被认为与 与歌曲相关的大脑区域的组织。在斑马雀中， 例如，感觉和感觉运动的学习与剧烈的变化重叠 歌曲相关神经元的数量、大小和连接性。这个 提出的第一项研究将采用比较神经解剖学方法 为了更好地定义神经变化和感觉之间的关系 感觉运动学习。声带解剖的发育性变化 细胞核将在沼泽麻雀中进行测量，在沼泽麻雀中， 声乐学习的各个阶段在时间上是完全分开的。下一步，神经 记住声乐模型可能需要的更改将是 已确认身份。将使用隔音来延长关键的 斑马雀感觉学习的时期。那么它将会是 确定了这种操作如何影响神经变化的时间 在开发宋代地区方面。最后，确定歌曲学习如何 影响宋氏核团的组织，神经解剖学测量 将与歌曲复杂性的个体差异相关。 此外，听觉体验影响生长的能力， 感觉或感觉运动过程中神经元的保留或增加 将对学习情况进行评估。存在关键的学习周期，用于 语言习得、社会依恋和 印记。该提案的长期目标是理解神经 这些独特的敏感期背后的机制和 确定如何通过经验依赖来存储信息 调节发育中的神经系统。

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.