Seasonal and Hormonal Effects on Auditory Processing

项目总结 甘贝尔的白冠麻雀是季节性繁殖的鸣禽。像许多其他鸣禽一样，它们在歌唱行为以及支持歌唱产生的神经回路的形态和生理方面表现出戏剧性的季节性差异。雄激素和雌激素类固醇性激素调节这些季节变化。虽然许多工作都集中在鸣禽发声过程中季节性可塑性的激素机制上，但相对较少的工作是研究季节性和荷尔蒙对鸣禽听觉加工的影响。初步的听觉脑干反应(ABR)数据表明，繁殖条件下的白冠麻雀与非繁殖鸟类相比，阈值和潜伏期显著增加；然而，对这些影响的详细评估仍有待完成。我的研究重点是用白冠麻雀作为模型，进一步描述季节性和荷尔蒙对听觉功能的影响。使用细胞外单一单位记录方法，特定目标1将确定季节性差异起源于听觉系统的哪里。具体目标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了这些变化。最后，特定的目标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保守。

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.