Fig. 3.

Higher magnification of differential expression in vocal nuclei. A: Nissl-stained (cresyl violet, left) and emulsion-dipped slides (darkfield microscopy, right) of higher power views of glutamate receptor subunits/subtypes in situ hybridization images that show prominent differential expression in zebra finch cerebral (upper four rows), thalamic (aDLM, fifth row), and midbrain (DM, sixth row) vocal nuclei. B: Examples of glutamate receptor subunit/subtype differential expression in small vocal nuclei NIf (low GluR3) and MO (low mGluR3). These differences are not as great as those seen in the large cerebral vocal nuclei. C: Examples of the medial part of the anterior vocal pathway nuclei with differential expression patterns that matched their lateral counterparts (higher NR2A in m-Area X and lower mGluR1 in mMAN). D: Higher power view of GluR4 and mGluR1 expression in the sparse, large cells (arrows) of l-Area X. In the striatum surrounding Area X (right of dashed lines) both large and smaller cells express high levels of these genes. E: Higher power view of differential expression of GluR1 and GluR4 in HVC. Scale bars = 300 μm in A,D,E; 200 μm in B,C.