Seasonal and Hormonal Effects on Auditory Processing

项目摘要 甘贝尔白冠麻雀是季节性繁殖的鸣禽。像许多其他鸣禽一样，它们在鸣叫行为以及鸣叫产生的神经回路的形态和生理上表现出戏剧性的季节差异。雄激素和雌激素类固醇性激素介导这些季节性变化。虽然很多工作都集中在鸣禽发声的季节性可塑性的激素机制，相对较少的工作调查季节和激素对鸣禽听觉处理的影响。初步的听觉脑干反应（ABR）的数据表明，繁殖条件下的白冠麻雀有显着增加的阈值和lavirs比非繁殖鸟类，但是，这些影响的详细评估仍有待完成。我的研究重点是使用白冠麻雀作为模型，进一步表征季节和激素对听觉功能的影响。使用细胞外单单位记录方法，具体目标1将确定在听觉系统的季节性差异起源。具体目标2将确定哪些激素受体介导这些变化，利用各种激素治疗，免疫组织化学和ABR记录。最后，具体目标3将确定在外周/脑干听觉系统中观察到的季节性差异是否在前脑处理区域中保留。

PROJECT SUMMARY Gambel's white-crowned sparrows are songbirds that breed seasonally. Like many other songbirds, they exhibit dramatic seasonal differences in song behavior, and in the morphology and physiology of the neural circuit underlying song production. Androgenic and estrogenic steroid sex hormones mediate these seasonal changes. While much work has focused on the hormonal mechanisms underlying seasonal plasticity in songbird vocal production, comparatively little work has investigated seasonal and hormonal effects on songbird auditory processing. Preliminary auditory brainstem response (ABR) data demonstrate that breeding condition white-crowned sparrows have significantly increased thresholds and latencies than non-breeding birds; however, a detailed assessment of these effects remains to be accomplished. The focus of my research is to use white-crowned sparrows as a model for further characterizing seasonal and hormonal influences on auditory function. Using extracellular single-unit recording methods, Specific Aim 1 will determine where in the auditory system seasonal differences originate. Specific Aim 2 will identify which hormone receptors mediate these changes by utilizing a variety of hormone treatments, immunohistochemistry and ABR recording. Finally, Specific Aim 3 will determine if seasonal differences observed in the peripheral/brainstem auditory system are conserved in forebrain processing regions.