LHRH neuronal subtypes have multiple origins in chickens.

Previous studies indicate that LHRH neurons of the septal-preoptic area originate in the olfactory epithelium. In the current study, we found that LHRH neurons entering the telencephalon from the olfactory nerve were not continuous with LHRH neurons in the thalamus. In addition, ablation of the olfactory placode eliminated LHRH neurons in the telencephalon but did not eliminate LHRH neurons in the thalamus. We propose that there are at least two sites of LHRH neuron production, the olfactory epithelium and the diencephalon.