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.