A novel tool to capture neural activity across an entire brain using C-FOS as an indicator

Immunohistochemical staining for the expression of the immediate early gene c-Fos is a powerful tool to measure neuronal activation of neurons across an entire brain. The results of c-Fos immunostaining are often quantified by counting the number of immunolabeled cells in a region of interest (ROI) determined by the experimental conditions. While powerful for confirming differences in neural activity in the ROI, this technique is time-consuming, inefficient, and ignores valuable information about the widespread network activity across an entire brain. In order to analyze c-Fos expression across an entire brain, we developed a novel Comprehensive Expression and Activity Assessment Tool (CEAT). CEAT is a semi-automated tool to identify cells in brain slices, quantify the activity through a variety of measures, and locate the activity within a particular region in the brain. In this paper we used a simple experiment examining visual processing in a mouse model in order to demonstrate the validity of the tool. Subsequent experiments will use this tool explore differences in neuronal activity of mouse models for neurological disorders in comparison to wild type mice.