James Logan S, Sakata Jon T
Department of Biology, McGill University, Montreal, Quebec, Canada.
Department of Biology, McGill University, Montreal, Quebec, Canada
J Neurophysiol. 2015 Oct;114(4):2328-39. doi: 10.1152/jn.00688.2015. Epub 2015 Aug 26.
Understanding the factors that predict and guide variation in behavioral change can lend insight into mechanisms of motor plasticity and individual differences in behavior. The performance of adult birdsong changes with age in a manner that is similar to rapid context-dependent changes to song. To reveal mechanisms of vocal plasticity, we analyzed the degree to which variation in the direction and magnitude of age-dependent changes to Bengalese finch song could be predicted by variation in context-dependent changes. Using a repeated-measures design, we found that variation in age-dependent changes to the timing, sequencing, and structure of vocal elements ("syllables") was significantly predicted by variation in context-dependent changes. In particular, the degree to which the duration of intersyllable gaps, syllable sequencing at branch points, and fundamental frequency of syllables within spontaneous [undirected (UD)] songs changed over time was correlated with the degree to which these features changed from UD song to female-directed (FD) song in young-adult finches (FDyoung). As such, the structure of some temporal features of UD songs converged over time onto the structure of FDyoung songs. This convergence suggested that the FDyoung song could serve as a stable target for vocal motor plasticity. Consequently, we analyzed the stability of FD song and found that the temporal structure of FD song changed significantly over time in a manner similar to UD song. Because FD song is considered a state of heightened performance, these data suggest that age-dependent changes could reflect practice-related improvements in vocal motor performance.
了解预测和指导行为变化差异的因素，有助于深入洞察运动可塑性机制和行为的个体差异。成年鸟鸣的表现会随着年龄变化，其方式类似于鸟鸣对快速情境依赖的变化。为揭示发声可塑性机制，我们分析了白腰文鸟歌声中与年龄相关变化的方向和幅度的差异，在多大程度上可由情境依赖变化的差异来预测。采用重复测量设计，我们发现与年龄相关的发声元素（“音节”）的时间、顺序和结构变化的差异，显著可由情境依赖变化的差异预测。具体而言，自发（无定向，UD）歌声中音节间间隔的持续时间、分支点处的音节顺序以及音节的基频随时间变化的程度，与这些特征在年轻成年雀类从UD歌声到雌鸟导向（FD）歌声变化的程度相关（FDyoung）。因此，UD歌声的一些时间特征的结构随时间逐渐趋向于FDyoung歌声的结构。这种趋同表明，FDyoung歌声可作为发声运动可塑性的稳定目标。因此，我们分析了FD歌声的稳定性，发现FD歌声的时间结构随时间显著变化，其方式类似于UD歌声。由于FD歌声被认为是一种表现增强的状态，这些数据表明与年龄相关的变化可能反映了发声运动表现中与练习相关的改善。
