Figure 2

ZENK⁺ neuronal populations in the pigeon brain. Pigeon brain sections at Karten/Hodos coordinates P1.25 (a), A5.00 (d), and A9.25 (g) stained with the 7B7-A3 antibody. Insets (dashed boxes) are shown below the corresponding images. In the absence of stimulation ZENK-positive nuclei can be detected throughout the pigeon brain in the (b) nucleus magnocellularis; (c) nucleus vestibularis descendens (VeD) and spinal trigeminal nucleus (SpV); (e) lateral habenular nucleus (HL) and nucleus dorsomedialis posterior thalami (DMP); (f) layer 7 and 10 of the tectum opticum; (h) hyperpallium apicale (HA), hippocampal formation (HF), hyperpallium intercalatum (HI), and mesopallium intermedioventrale, pars medialis (MIVm); and (i) nidopallium (N) and striatum laterale (LSt). Black arrowheads highlight ZENK positive neuronal populations. The white arrowhead in (i) highlights the lack of ZENK staining in the entopallium (E). Scalebars represent 1 mm in upper row and 100 μm in insets.