Molecular Mapping of Movement-Associated Areas in the Avian Brain: A Motor Theory for Vocal Learning Origin
Figure 3
Movement-induced ZENK expression in garden warblers.
A. Darkfield images of medial (top) and lateral (bottom row) sagittal sections from birds sitting relatively still in room day light (a, b) or dim night light (c, d) and birds making mostly flights in day light (e, f) or wing whirring in dim light (g, h). The anatomical profiles to the right show the extent of the movement-induced (red) and visual-induced (blue) gene expression areas. Note that the PLN and PLMV areas differ slightly in shape between garden warblers (panel Af,h) and zebra finches (Fig. 2A), due to differences in the shapes of the N and MV cerebral subdivisions and that the warbler sections are more lateral. Anterior is right, dorsal is up. Scale bar, 2 mm. B. Quantification of ZENK expression levels in different brain areas from the four groups of warblers. Anterior and posterior areas were grouped according to their relative location to vocal nuclei. * = p<0.05, one-way ANOVA followed by Holm-Sidak multi-comparison test, comparing moving groups with still groups for each light condition; each movement group showed significant differences with each still group. # = p<0.001 for an increase in Cluster N in dim versus day light groups, whether still or moving. Error bars, S.E.M. C. Correlation between the amount of wing beats and ZENK expression levels shown in exponential (top row) and double natural logarithmic (bottom row) graphs for example areas. Each dot represents the value of one bird. D. Statistical analyses: (a) one-way ANOVA followed by Holm-Sidak all-pairwise multi-comparison test for the brain areas in (B); (b) exponential regression stats (examples in C, top row); (c) linear regression stats on double-logarithmic transformation of the data (C, bottom row). Red text are significant differences (p<0.05); n.s. = not significant.