Impulse: The Premier Undergraduate Neuroscience Journal (Aug 2023)
Female Mice Show Increased V1 Inhibitory Neuronal Activity When Viewing Novel and Familiar Visual Stimuli Compared to Male Mice
Abstract
The primary visual cortex (V1) is the first area of visual stimuli integration, the perception and processing of stimuli through the optic tract and associated brain regions. V1 recording data showed increased inhibitory neuronal activity in mice viewing novel images compared to viewing familiar images. The V1 area has also been suggested to show a correlation between endogenous estrogen and neuronal activity. Despite these findings, female mice remain generally underrepresented in research, leading to a gap in the understanding of sex-specific differences in stimuli integration. In this paper, we examine 2-photon calcium imaging data from the Allen Institute, consisting of V1 area neuronal activity of two mouse models with identified inhibitory neurons; VIP-IRES-Cre x Ai148 and Sst-IRES-Cre x Ai148. Prior review led to our initial hypothesis that female mice V1 activity will show a greater response to novel images and generally similar responses to familiar images. After filtering the data for sex and the specific image displayed to the mice using Python 3, change in fluorescence over baseline fluorescence (dF/F) traces were analyzed for individual cells from each sex. Cell traces were quantified by their frequency of significant response peaks throughout a five-minute period. We found that when viewing both novel and familiar images, female mice exhibited a significantly higher amount of inhibitory neuronal activity compared to male mice. These findings suggest inherent neurophysiological differences between the sexes affecting the integration of visual stimuli, which would have previously gone unnoticed as a consequence of the lack of use of sex as a biological variable Abbreviations: dF/F – Change in Fluorescence over Fluorescence; GABA – Gamma- Aminobutyric Acid; Glu – Glutamate; LGN – Lateral Geniculate Nucleus; Ophys – Optophysiology; SABV – Sex as A Biological Variable; V1, VISp – Primary Visual Cortex; 2-p – 2-photon calcium
