Gradual increase in neuronal density of rats’ lateral geniculate nucleus from anterior to posterior

OBJECTIVE: To clarify the organization of the rat lateral geniculate nucleus (LGN).METHODS: A total of 50 male Sprague-Dawley albino rats of 2 months of age were used in this study carried out in the Iran University of Medical Sciences, Tehran, Iran in Spring-Fall 2007. The rats were cardially perfused under deep ether anesthesia, first with a small amount of saline then with a fixative solution containing 4% paraformaldehyde and 0.2% glutaraldehyde in 0.1M phosphate buffer pH 7.2. The brains were removed, processed, and then 50 um coronal sections of the LGN were cut and divided into 3 groups: anterior, middle, and posterior third. Cresyl violet stained sections were studied by light microscopy and counts of neurons were carried out with Olysiabio report software of Olympus Microscope in every other section.RESULTS: We observed that the neuronal density in the anterior, middle, and posterior thirds were statistically different.CONCLUSION: The concentration of neuronal terminals and neuronal connections causes changes in neuronal density.