Fig. S3.

Glutamatergic, cholinergic, and GABAergic synaptic terminal arrangement in area X. (A and B) Sections of area X tissue immunolabeled with antibodies against ChAT (A) and VGluT2 (B). (C) Merged image of A and B. (D, Left) Low probability of overlap of VGluT2⁺ and ChAT⁺ puncta (n = 7 birds); (Center) Same low probability of overlap when the VGluT2 image was rotated 90°; (Right) high probability of overlap of VGluT2-positive puncta in adjacent optical sections. (E–H) Same as in A–D, for immunolabeling for vesicular GABA transporter (VGaT) and VGluT2 puncta.