A pallial-basal-ganglia-thalamic-pallial loop in songbirds is involved in vocal motor learning. Damage to its basal ganglia part, Area X, in adult zebra finches has been noted to have no strong effects on song and its function is unclear. Here we report that neurotoxic damage to adult Area X induced changes in singing tempo and global syllable sequencing in all animals, and considerably increased syllable repetition in birds whose song motifs ended with minor repetitions before lesioning. This stuttering-like behavior started at one month, and improved over six months. Unexpectedly, the lesioned region showed considerable recovery, including immigration of newly generated or repaired neurons that became active during singing. The timing of the recovery and stuttering suggest that immature recovering activity of the circuit might be associated with stuttering. These findings indicate that even after juvenile learning is complete, the adult striatum plays a role in higher level organization of learned vocalizations.

Although vocal communication is wide-spread in animal kingdom, the use of learned (in contrast to innate) vocalization is very rare. We can find it only in few animal taxa: human, bats, whales and dolphins, elephants, parrots, hummingbirds, and songbirds. There are several parallels between human and songbird perception and production of vocal signals. Hence, many studies take interest in songbird singing for investigating the neural bases of learning and memory. Brain circuits controlling song learning and maintenance consist of two pathways -a vocal motor pathway responsible for production of learned vocalizations and anterior forebrain pathway responsible for learning and modifying the vocalizations. This review provides an overview of the song organization, its behavioural traits, and neural regulations. The recently expanding area of molecular mapping of the behaviour-driven gene expression in brain represents one of the modern approaches to the study the function of vocal and auditory areas for song learning and maintenance in birds.

Abstract. Song learning and production have many parallels with speech and the mechanisms of their control have been studied extensively. There is an increasing amount of evidence that the dopaminergic system is involved in song learning and maintenance. Dopamine receptors show distinct expression in most of the song nuclei and the highest levels in Area X of the striatum. Here we have investigated whether the mRNA expressions for D1A, D1B, and D2 receptors in Area X are associated with quantitative and/or qualitative characteristics of zebra finch song. We found that quantitative parameters of song such as the amount of songs sang, motif duration, and numbers of distinct syllables and/or notes per motif did not correlate with expression of D1A, D1B nor D2 receptors in Area X or surrounding striatum. However, the mean accuracy of the song correlated negatively with D1A receptor expression levels and the sequential match correlated positively with D2 receptor expression levels in Area X relative to the surrounding striatum. These data suggest that dopamine receptor densities in Area X are associated with song variability.