Distribution of Thalamic Projection Neurons to the Wulst in the Japanese Quail (Coturnix coturnix japonica)

The distribution of thalamic projection neurons to the Wulst was examined in the Japanese quail (Coturnix coturnix japonica) using the retrograde transport of wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) method. After injection of WGA-HRP into the unilateral Wulst, retrogradely labeled neurons (RLneurons) were found ipsilaterally in zones A and B of the nucleus dorsolateralis anterior thalami pars lateralis (DLL), the nucleus dorsolateralis anterior thalami pars magnocellularis (DLAmc), the nucleus dorsolateralis anterior thalami pars medialis (DLM) and the nucleus intercalatus thalami (ICT). RL-neurons were also found in the contralateral zone A of the DLL and nucleus tractus septomesencephalicus (nSMT). The ipsilateral DLL had more RL-neurons than those of the contralateral DLL. The thalamo-Wulst projection neurons in the ipsilateral DLM and ICT, and the contralateral nSMT have been newly identified in the present study. The distribution of the RLneurons in zones A and B in the DLL, DLAmc and the DLM and ICT closely corresponded to areas which were discovered as retinorecipient zones in our previous reports13,14). Therefore these nuclei could be considered as relay stations in the retinoWulst pathway. Anim. Sci. Technol. (Jpn.) 64 (10): 978-986, 1993