Lateralization of syringeal function during song production in the canary

Abstract

The canary (Serinus canaria) vocal organ, the syrinx, has two separate sound sources, one in the cranial end of each bronchus. Previous investigations of whether song syllables are produced unilaterally or bilaterally have provided two contradictory results, as one researcher suggested that almost all syllables are produced by the left side of the syrinx alone, whereas another researcher suggested that both sides contribute similarly to all syllables. Our experiments, which involved unilateral bronchus plugging followed later by denervation of the ipsilateral syringeal muscles, attempted to resolve this disagreement. The males with right bronchus plugs, singing on the left side of the syrinx alone, produced nearly normal songs, whereas the birds with left bronchus plugs, singing on the right side, sang quite poorly. Interpretation of these data is difficult because it is not clear how syringeal function would be affected if the airflow rate through the intact side is increased above normal, nor is it known if the bird can compensate for bronchus occlusion. Nonetheless, we suggest that in male canaries most syllables are normally sung by the left side alone, with some syllables being produced by the right side alone and some being sung by both sides together. Right nerve section had little effect on the right-bronchus-plugged males' ability to sing, but the repertoires of the left-plugged males were altered after left nerve section, indicating the possibility that signals carried by the left nerve exert an influence on the contralateral side.

Functional MRI of the zebra finch brain during song stimulation suggests a lateralized response topography

“…Bilateral asymmetry with either left-sided or right-sided dominance, or differential dual specialization, has been previously observed in songbirds in relation to both central and peripheral control of song production (49)(50)(51)(52). As far as song perception is concerned, increased neuronal responsiveness to behaviorally relevant song stimuli has been observed in the field L complex and HVC on the right side in starlings (53,54).…”

Pattern of Interhemispheric Synchronization in HVc During Singing Correlates With Key Transitions in the Song Pattern

“…Early pioneering studies by Nottebohm demonstrated that each syringeal half contributes differently to the bird's song (Nottebohm 1971). In the canary, for example, cutting the syringeal nerve on the left side causes Ͼ80% of the syllables of the bird's song to be omitted whereas identical manipulation on the right side causes only minor changes in song output (Hartley and Suthers 1990;. The source of this lateralization may originate in part from hemispheric differences between forebrain song control nuclei because HVc lesions, in both canaries and zebra finches, cause deficits that differ with the side of the lesion .…”

Mismatch in sexual dimorphism of developing song and song control system in blue-capped cordon-bleus, a songbird species with singing females and males

“…In adulthood, female canaries sing only occasionally and if at all, generally with few unstructured songs compared to adult males (Pesch and Güttinger, 1985). Female canary song can be activated by testosterone (e.g., Shoemaker, 1939;Hartley and Suthers, 1990;Hartog et al, 2009). This potential to sing correlates with the differentiation of their song control areas, which is relatively smaller as compared to canary males but relatively larger as compared to female zebra finches (Nottebohm and Arnold, 1976;Nottebohm, 1980).…”