Seasonal and Hormonal Effects on Auditory Processing

描述（由申请人提供）：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背后的神经回路的形态和生理上表现出巨大的季节性差异。雄激素和雌激素类固醇性激素调节这些季节变化。虽然很多工作都集中在鸣禽声音产生的季节性可塑性的激素机制上，但相对较少的工作研究了季节性和激素对鸣禽听觉加工的影响。初步的听觉脑干反应（ABR）数据表明，繁殖条件下白冠麻雀的阈值和潜伏期明显高于非繁殖鸟类；然而，对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。使用细胞外单单元记录方法，Specific Aim 1将确定听觉系统中季节性差异的起源。特异性目标2将通过利用各种激素治疗、免疫组织化学和ABR记录来确定哪些激素受体介导这些变化。最后，Specific Aim 3将确定外周/脑干听觉系统中观察到的季节性差异是否在前脑加工区域中保守。

DESCRIPTION (provided by applicant): 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. PUBLIC HEALTH RELEVANCE: A growing body of literature links human hearing and steroid hormones, but the nature and mechanism of these interactions remain unknown. To better understand the extrinsic and intrinsic conditions that regulate the sensitivity and selectivity of hearing as related to communication signals, I have chosen to study the peripheral and central auditory system of songbirds. The research I propose here will use white-crowned sparrows as a model to better understand the hormonal mechanisms that influence and underlie normal hearing function, and is thus directly relevant to the mission of NIDCD.