Biology Department, Wesleyan University, Middletown, CT 06459, United States.
Brain Lang. 2010 Oct;115(1):29-44. doi: 10.1016/j.bandl.2009.09.006. Epub 2009 Oct 23.
Song learning, maintenance and production require coordinated activity across multiple auditory, sensory-motor, and neuromuscular structures. Telencephalic components of the sensory-motor circuitry are unique to avian species that engage in song learning. The song system shows protracted development that begins prior to hatching but continues well into adulthood. The staggered developmental timetable for construction of the song system provides clues of subsystems involved in specific stages of song learning and maintenance. Progressive events, including neurogenesis and song system growth, as well as regressive events such as apoptosis and synapse elimination, occur during periods of song learning and the transitions between variable and stereotyped song during both development and adulthood. There is clear evidence that gonadal steroids influence the development of song attributes and shape the underlying neural circuitry. Some aspects of song system development are influenced by sensory, motor and social experience, while other aspects of neural development appear to be experience-independent. Although there are species differences in the extent to which song learning continues into adulthood, growing evidence suggests that despite differences in learning trajectories, adult refinement of song motor control and song maintenance can require remarkable behavioral and neural flexibility reminiscent of sensory-motor learning.
歌曲学习、维持和产生需要听觉、感觉运动和神经肌肉结构的协调活动。参与歌曲学习的鸟类物种的感觉运动回路的端脑成分是独特的。歌唱系统的发育过程很长，从孵化前就开始了，但一直持续到成年期。歌唱系统构建的分期发育时间表为参与特定阶段歌曲学习和维持的子系统提供了线索。在歌曲学习期间以及在发育和成年期间，可变和刻板的歌曲之间的过渡期间，会发生包括神经发生和歌唱系统生长在内的渐进事件，以及包括细胞凋亡和突触消除在内的退行性事件。有明确的证据表明，性腺类固醇会影响歌曲属性的发育，并塑造潜在的神经回路。歌曲系统发育的某些方面受感官、运动和社会经验的影响，而其他方面的神经发育似乎与经验无关。尽管在歌曲学习持续到成年的程度上存在物种差异，但越来越多的证据表明，尽管学习轨迹存在差异，但成年后对歌曲运动控制和歌曲维持的精细调整可能需要显著的行为和神经灵活性，这让人联想到感觉运动学习。
