The Immunohistochemical Studies of Projections Linking The Auditory Thalamus and Neurosecretory Hypothalamus in The Brain of Non-Songbird

The connectivity between a region surrounding the thalamic auditory nuclei,the nucleus ovoidalis (Ov),and nucleus ventromedialis hypothalami (VMN) was explored in the ring doves by using a tracer,Biotinylated Dextran Amine (BDA) and immunohistochemistry.The results revealed that the Ov surround,which we term the nucleus ovoidalis shell (Ov shell),contained met-enkephalin immunoreactive (ENK-ir) neurons sent a projection directly into the VMN following an injection of BDA into the posterior Ov (Ovp).Since the pathways from Ov Shell to VMN and the terminal fields in entire VMN showed densely distributed ENK-ir,present data suggested that the immunoreactive perikarya within Ov shell might contribute to enkephalinergic-neuropil within VMN.