Lateralization of the song nucleus in the zebra finch Taeniopygia guttata

Abstract The vocal control system of songbirds has a significant laterality in song output control, and the adult zebra finch Taeniopygia guttata has a significant advantage in the right high vocal center (HVC) in song frequency domain and intensity control. We investigated the allometric relationship between song control nucleus and brain scale in zebra finches, investigated whether HVC and the robust nucleus of the archistriatum (RA) had similar differences in volume, cell density and cell number, and whether Testosterone (T) played a role in these differences. The results of Nissl staining and Immunohistochemistry show that although there is no significant difference between left and right HVC in nucleus volume, cell density and cell number (P > 0.05), the correlation parameters on the right side are always higher than those on the left side. On nucleus volume and cell number, both sides of the RA have no significant different (P > 0.05), but on the cell density has a significant (P < 0.05). Testosterone receptors (TR), on both sides the HVC and RA, have no significant difference (P > 0.05). The growth rate of left and right HVC and RA is consistent with that of brain (K > 1). HVC and RA are well fitted to brain length, width and height, and the intercept is also very close. What’s more, the song nucleus always show negative growth relationship with the three-dimensional parameters of the brain. Therefore, while the living environment remains relatively constant, songbirds will continue to strictly follow the existing allometric growth pattern, and any individuals that deviate seriously from this development pattern will show more inadaptability.