AUDITORY EXPERIENCE AND ADULT NEURON TURNOVER IN BIRDS

描述：(改编自申请者摘要) 在包括人类在内的许多脊椎动物中，神经发生一直持续到成年期。一个 对控制神经元增加和存活的因素的理解可能 最终导致对成人神经发生功能的洞察，并建议 大脑修复的机制。在成年温血脊椎动物中，最 鸟类端脑中广泛存在神经元的产生。在……里面 鸣禽，许多新的神经元被插入到高声中枢(HVC)， 感知和产生习得发声所必需的区域。 新的HVC神经元取代了已经死亡的旧神经元。最近的研究表明， 听觉输入是正常的神经元替换速率所必需的。可用 数据表明，耳聋会减少HVC神经元的数量 并延长它们随后的生存时间。拟议的工作将直接测试 已经成功整合的神经元的寿命是否 增加了耳聋前的HVC。更多的研究将确定 耳聋会影响成年形成的神经元的产生或早期存活。 一项损伤研究将测试大脑外侧大细胞核是否 新纹状体前部(LMAN)是歌曲学习所必需的区域，参与 在听觉控制下HVC神经元的翻转。 播放同种歌曲会增加HVC神经元的活动率 而最大速率是通过回放鸟儿自己的歌声获得的。因此， 耳聋对HVC神经元周转的影响可能是由于剥夺了鸟类的 歌曲相关的听觉刺激。拟议中的实验将系统地 使听力完好的鸟类无法获得自我产生的听觉反馈 和/或同种歌曲来验证这一假设。我们将对比这些影响 在没有完全阻止的情况下，这些操作会改变， 从歌唱中自我产生的听觉反馈。总的来说，这些研究将 探索控制成体神经元添加的感觉要求 一个离散的、特征良好的神经系统内的损失，控制着一个习得的 发声行为。

DESCRIPTION: (adapted from applicant's abstract) Neurogenesis persists into adulthood in many vertebrates including humans. An understanding of the factors that control neuron addition and survival may ultimately lead to insights on the functions of adult neurogenesis and suggest mechanisms for brain repair. In adult warm-blooded vertebrates, the most widespread production of neurons occurs in the avian telencephalon. In songbirds, many new neurons are inserted into the High Vocal Center (HVC), a region necessary for the perception and production of learned vocalizations. New HVC neurons replace older neurons that have died. Recent work shows that auditory input is necessary for normal rates of neuronal replacement. Available data suggest that deafening decreases the numbers of HVC neurons incorporated and prolongs their subsequent survival. Proposed work will directly test whether the life span of neurons that have been successfully incorporated into HVC prior to deafening is augmented. Additional studies will determine whether deafening influences the production or early survival of adult-formed neurons. A lesion study will test whether the lateral magnocellular nucleus of the anterior neostriatum (lMAN), an area necessary for song learning, participates in the auditory control of HVC neuron turnover. Playbacks of conspecific song produce increased rates of HVC neuron activity and maximal rates are obtained with playbacks of the bird's own song. Thus, the effects of deafening on HVC neuronal turnover may be due to depriving birds of song-related auditory stimulation. Proposed experiments will systematically deprive hearing-intact birds of access to self-generated auditory feedback and/or conspecific song to test this hypothesis. We will contrast these effects with those following manipulations that alter, without completely blocking, self-generated auditory feedback from singing. Collectively, these studies will explore the sensory requirements for the control of adult neuron addition and loss within a discrete, well-characterized neural system controlling a learned vocal behavior.