Immunohistochemical characterization of forebrain areas in the collared dove (Streptopelia decaocto)

The distribution of four neuroactive substances was studied in the telencep halon of the collared dove using enzyme- and immunohistochemistry. The dist ribution of acetylcholinesterase and dopamine was similar to that described in other birds. Galanin-immunoreactive fibres were found mainly in the pal eostriatum primitivum, the medial part of the parolfactory lobe (LPO) and t he lateral septal nucleus; galanin may interfere with acetylcholine activit y. Intense gastrin releasing peptide (GRP)-immunoreactivity was found in th e neuropil of LPO, the ventral paleostriatum and the caudal archistriatum; further GRP-immunoreactive varicosities were found in the neostriatum and t he hyperstriatum ventrale - particularly in its medial part - whereas GRP-i mmunoreactive cells occurred in the medial neostriatum, the hyperstriatum a ccessorium and the ventral archistriatum. These data help to define more pr ecisely several functional telencephalic systems, but no indications for sp ecific centers with a role in vocalization were found.