This study was carried out to investigate the spaciotemporal plasticity of intergeniculate leaflet in postnatal mongolian gerbil using genetically modified pseudorabies virus recombinant, which was a kind of excellent neurotracer with the ability to transpass the neuronal synaptic cleft. In addition, we tried to evaluate the special role of intergeniculate leaflet as a signal controler of circardian rhythm by expression of various nourotransmitters in suprachiasrnatic nucleus. The PRV-BaBlu, a genetically modified strain of PRV-Bartha with lac-Z gene, was injected into vitreous body of postnatal mongolian gerbil, and immunostained. The PRV-Bablu infected the neurons in intergeniculate leaflet of postnatal mongolian gerbil, and the degree of viral infection in postnatal period of experimental animals had tendency to increase with time consuming. This results showed that the mutant PRV-Bar-tha strain with lac-Z gene, PRV-BaBlu, was a very excellent neurotracer to localize the retinogeniculate tract with infection of neurons in intergeniculate leaflet specially.