hybridization for mRNA of genes differentially expressed in HVC, RA or entopallium. Expression, either up- or down-regulated in HVC and RA compared with the ENT, was as expected from the RNA-seq for all six depicted genes. Next to the high expression in HVC (small arrows for ALDH1A2, CNTFR, GPR83, GLI2, RASGRP1) or RA (large arrow for GPR83) of LD canaries, the selected genes are expressed in other, distinct brain regions, such as the medial striatum (large arrow for RASGRP1), the arcopallium (large arrow for CNTFR) and the mesopallium (large arrow for ALDH1A2). KCNQ5 is down-regulated in the HVC of the depicted SD canary but year-round highly expressed in the ENT (large arrow). Abbreviations: ALDH1A2, aldehyde dehydrogenase 1 family, member A2; CNTFR, ciliary neurotrophic factor receptor; GLI2, GLI family zinc finger 2; GPR83, G protein-coupled receptor 83; KCNH5, potassium voltage-gated channel, subfamily H (eag-related), member 5; RASGRP1, RAS guanyl releasing protein 1 (calcium and DAG-regulated). Shown are photomicrographs of autoradiograms of sagittal sections of the canary brain. Labelled areas appear darkened. The scale bar equals 5 mm.