Elizabeth Fashakin

Elizabeth Fashakin

PI: Jon Kaas, PhD, Department of Psychology

Anterior-Posterior Analysis of Neuronal Distribution Across the Left and Right Hemispheres of New World Monkeys

Recently, our group observed that the neuronal distribution of the primate cortex varies across the different functional areas of the neocortex, with lower densities at the frontal regions and an increase towards the visual areas. However, these former studies were executed on a single hemisphere and used various approaches to compare the left and right hemispheres. Therefore, in our current research, our lab group focused upon mapping the distribution of neurons and other cells densities of both hemispheres of 3 species of New world monkeys (Aotus trivirgatus, Saimiri and Callicebus) in order to observe if each hemisphere has any particularity in its cellular distribution when compared to the other. We performed a systematic analysis by cutting into even pieces of flattened cortex on each hemisphere. We then further processed these pieces using the Isotropic Fractionator, a method which transforms a tissue into a nuclei suspension of in which we can estimate the total number of cells. So far, our lab has observed that the primary visual cortex (V1) of both hemispheres contains approximately 44 million neurons. This emphasizes the hypothesis that there is no major distinction in the neuronal distribution trends between two hemispheres in the cerebral cortex of primates. However, a more detailed analysis is necessary to reveal additional features of the pattern of neuronal distribution in the primate brain.