Developmental learning involves nonsynaptic plasticity

许多神经科学家将学习解释为神经细胞之间称为突触的特殊连接的数量和/或强度的简单变化。这个研究项目测试了一个新的想法，即学习也重要地涉及神经细胞其他部分的分子变化，这些细胞控制着这些细胞相互交流所需的电活动的产生。学习是在年轻的鸣禽如何学习唱歌的背景下进行研究的，这与人类学习说话、演奏乐器或产生任何复杂的行为序列的方式类似。通过结合行为观察和记录以及解剖学、生理学、分子、计算和统计技术，研究小组将验证这样一种假设，即发育中的歌唱变化伴随着不位于突触的细胞电活动的变化。他们还将确定这些电变化的机械基础。这项研究将揭示大脑如何在一生中存储所学信息的重要新细节。它还将为学生研究助理提供广泛的多学科培训，以及开发新的分析软件和计算模型，这些将使更广泛的神经科学社区受益（这些将通过一个公众可访问的网站免费提供）。还将制作标有国家规定的具体高中学习目标的神经科学和数学视频，并通过国家分类门户网站提供给教师。最后，研究小组开展了各种各样的社区教育项目，特别是与神经科学、鸟鸣和学习有关的项目。这些活动包括K-12学校的项目以及老年人的学术课程。关于鸟鸣学习背后的大脑区域和回路，我们已经了解了很多。因此，科学家们知道在哪里寻找由学习引起的变化（一个名为HVC的区域），但他们不知道是什么神经变化编码了歌曲的听觉记忆。提出的研究测试了HVC神经元中特定的非突触离子电流的变化有助于听觉记忆编码的新假设。鸣禽的听觉学习可以很容易地通过控制对导师歌曲的接触来操纵。初步数据表明，HVC神经元固有的细胞体/轴突通道特性在歌唱发育过程中以经验依赖的方式发生变化。研究小组最近对决定成年雀HVC神经元生理的离子电流进行了表征和建模，现在可以进行拟议的发育研究。拟议的研究将测试关于特定离子电流的发展出现的假设，因为它们与感官学习有关。这将导致对负责这种学习的潜在分子机制的可测试假设。作为这个项目的一部分，团队还将纠正关于雌性斑胸草雀HVC的错误观点。长期以来，人们一直认为HVC缺乏男性特有的连通性，但新的数据显示，女性和男性的HVC具有相同的细胞类型和外在连通性模式。由于女性表现出对导师歌曲的听觉学习，但不会唱歌，因此对女性HVC的分析将为所提出的假设提供关键检验。总之，拟议中的实验将为早期感觉信息如何作为持续一生的稳定记忆痕迹存储的基本问题提供线索。

Many neuroscientists explain learning as a simple change in the number and/or strength of specialized connections between nerve cells called synapses. This research project tests a new idea, that learning also importantly involves molecular changes in other parts of nerve cells which control the production of electrical activity required for these cells to communicate with each other. Learning is studied in the context of how young songbirds learn to sing, which happens in a similar way to how humans learn to speak, play a musical instrument, or produce any complicated sequence of behavior. Using a combination of behavioral observation and recording together with anatomical, physiological, molecular, computational and statistical techniques, the research team will test the hypothesis that developmental singing changes are accompanied by changes in cell electrical activity that are not located at synapses. They will also identify the mechanistic basis for these electrical changes. This research will reveal important new details about how the brain can store learned information for an entire lifetime. It will also provide student research assistants with broad multidisciplinary training, as well as developing new analytical software and computational models that will benefit the broader neuroscience community (these will be made freely available through a publically-accessible web site). Neuroscience and mathematics videos tagged to specific State-mandated high school learning objectives will also be produced, which will be made available to teachers via a cataloged State portal. Finally, the research team conducts a wide variety of community education programs specifically related to neuroscience, birdsong, and learning. These activities include programs for K-12 schools as well as a scholarly course for senior citizens.Much is known about the brain areas and circuits that underlie birdsong learning. Consequently, scientists know where to look for learning-induced changes (an area named HVC), but they do not know what neural changes encode the auditory memories of song. The proposed research tests the novel hypothesis that changes in specific, non-synaptic ionic currents in HVC neurons contribute to the encoding of auditory memories. Songbird auditory learning can be readily manipulated by controlling exposure to a tutor song. Preliminary data show that the intrinsic cell body/axonal channel properties of HVC neurons change in an experience-dependent manner during song development. The research team's recent characterization and modeling of the ionic currents that determine the physiology of HVC neurons in the adult finch now allow for the proposed developmental studies. Proposed studies will test hypotheses about the developmental emergence of specific ionic currents as they relate to sensory learning. This will lead to testable hypotheses about the underlying molecular mechanisms responsible for this learning. As part of this project, the team will also correct mistaken views about HVC of female zebra finches. Long thought to lack male-typical connectivity, new data show that female and male HVC have the same cell types and patterns of extrinsic connectivity. Since females show auditory learning of tutor song, but do not sing, analysis of female HVC will provide a critical test of the proposed hypotheses. Together, the proposed experiments will provide clues to fundamental questions about how early sensory information is stored as a stable memory trace that lasts a lifetime.