Androgens and isolation from adult tutors differentially affect the development of songbird neurons critical to vocal plasticity.
Androgens and isolation from adult tutors differentially affect the development of songbird neurons critical to vocal plasticity.
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DOI：
10.1152/jn.2001.85.1.34
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发表时间：
2001
影响因子：
2.5
通讯作者：
F. S. Livingston;Richard Mooney
中科院分区：
文献类型：
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作者：
F. S. Livingston;Richard Mooney
鸣禽的鸣唱学习发生在幼年敏感期。一种观点认为，这一敏感期是由端脑新纹状体外侧大细胞核（LMAN）神经元电生理特性的变化来调节的，LMAN是歌曲发育的关键结构，但不是成年人的歌唱。这个想法的一个必然结果是，影响歌曲学习的速度和质量的操作将伴随着影响LMAN的电生理特性的发展。已知影响歌曲发展的操作包括用外源性雄激素治疗少年雄性斑胸草雀，这导致异常截断的成年歌曲，以及将少年与成年导师及其歌曲隔离，这延长了歌曲学习的敏感期。在此之前，我们表明，突触传递LMAN的变化超过正常的歌曲发展，这些变化是加速或延迟，分别由雄激素治疗和隔离的成人导师。LMAN神经元的内在特性为类固醇激素和成人导师的经验提供了另一个潜在的调节靶点。事实上，先前的研究表明，由于低阈值钙峰，LMAN神经元爆发动作电位的能力以及LMAN中单个动作电位的宽度随着发育而减弱。在这里，我们分析了这些和其他内在的电生理功能的LMAN神经元在正常发展，然后测试是否早期雄激素治疗或隔离青少年从成人导师影响这些变化的时间。目前的研究表明，雄激素，但不隔离治疗改变LMAN神经元的进展，从爆发到nonbursting表型的发育时间。此外，其他内在的属性，包括半高尖峰宽度和尖峰后超极化（AHP）的幅度，被发现显着变化的发展，但只有变化的AHP雄激素敏感。有趣的是，所有的突触和内在的电生理特性，在LMAN研究的日期，只有半高尖峰宽度继续改变，在后期的少年阶段的歌曲学习。此外，在与成年导师隔离的情况下抚养青少年会暂时延迟这种特性的成熟。目前的研究结果强调，除了它们对LMAN的突触特性的影响，雄激素和成人导师的经验是LMAN神经元的内在特性的有效和选择性的调节器。
Song learning in oscine birds occurs during a juvenile sensitive period. One idea is that this sensitive period is regulated by changes in the electrophysiological properties of neurons in the telencephalic song nucleus lateral magnocellular nucleus of the anterior neostriatum (LMAN), a structure critical for song development but not adult singing. A corollary of this idea is that manipulations affecting the pace and quality of song learning will concomitantly affect the development of LMAN's electrophysiological properties. Manipulations known to affect song development include treating juvenile male zebra finches with exogenous androgens, which results in abnormally truncated adult songs, and isolation of the juvenile from adult tutors and their songs, which extends the sensitive period for song learning. Previously, we showed that synaptic transmission in LMAN changes over normal song development and that these changes are accelerated or retarded, respectively, by androgen treatment and isolation from an adult tutor. The intrinsic properties of LMAN neurons afford another potential target for regulation by steroid hormones and experience of adult tutors. Indeed previous studies showed that the capacity for LMAN neurons to fire action potentials in bursts, due to a low-threshold calcium spike, and the width of single action potentials in LMAN, wane over development. Here we analyzed these and other intrinsic electrophysiological features of LMAN neurons over normal development, then tested whether either early androgen treatment or isolating juveniles from adult tutors affected the timing of these changes. The present study shows that androgen but not isolation treatment alters the developmental time at which LMAN neurons progress from the bursting to nonbursting phenotype. In addition, other intrinsic properties, including the half-height spike width and the magnitude of the spike afterhyperpolarization (AHP), were found to change markedly over development but only changes to the AHP were androgen sensitive. Interestingly of all of the synaptic and intrinsic electrophysiological properties in LMAN studied to date, only the half-height spike width continues to change in the late juvenile stages of song learning. Furthermore raising juveniles in isolation from an adult tutor transiently delays the maturation of this property. The present results underscore that beyond their effects on LMAN's synaptic properties, both androgens and adult tutor experience are potent and selective regulators of the intrinsic properties of LMAN neurons.