The correlation between mouse behavior and cholinergic activity in the medial septum

Abstract

The neuromodulator acetylcholine supports learning, memory, and attention by modulating neural activity in the hippocampal formation. The primary source of acetylcholine release in the hippocampal formation stems from cholinergic projection neurons in the medial septum. However, little is known about the relationship between the activity of cholinergic neurons in the medial septum and real-time behavior. To further investigate this subject, we used fiber photometry to monitor the activity of cholinergic neurons using a genetically encoded Calcium indicator (GECI) while observing mouse behavior during free exploration through video recordings. The video recordings were analyzed with deep learning algorithms, namely DeepEthogram and DeepLabCut, to categorize each video frame into predetermined behaviors and track the animal’s position and orientation. GECI fluorescent cells (cholinergic neurons) were found by observing immunohistochemistry images of the mouse brain tissue. We present preliminary data on correlations of cholinergic activity with mouse behavior and 3D reconstruction of animal pose. Studying the link between cholinergic activity and behavior can lead to a better understanding of the hippocampal formation, which will be crucial in treating neurodegenerative diseases such as Alzheimer’s disease.