Abstract

Studying the longitudinal effects of chronic stress using a novel digital behavioral box system

Ghimire A, Kirca D, Hale P, Cerda I, Fitzgerald PJ, Ognjanovski N, Marino S, Kim D, Vijayakumar P, Watson BO
51st Annual Meeting of the Society for Neuroscience. 2022.

Stress in humans can lead to mental health conditions such as depression and anxiety. In rodents, we have powerful neuroscientific tools that are not available in humans, allowing for the study of neurobiologic circuitry that underlie mental health disorders in humans. While the behavior of mice exposed to chronic stress has been well studied, most prior work in this field has used relatively short-term tests (with a duration of minutes to hours) and does not measure behavior longitudinally or in conjunction with simultaneous brain electrophysiology. Furthermore, prior work utilizes experimenter-defined behavior tests, rather than assaying naturalistic behavior in the homecage. This is of particular importance given that depression and stress in humans manifest as changes to daily life including eating habits, energy level, motivation, sleep, and other symptoms. Such symptoms in humans are typically assessed using verbal reports. Efforts to more objectively quantify them use a “Digital Phenotyping'' approach with the help of smartphones and activity trackers. Here we present our “Digital Homecage”(DH) system for mice and rats which allows us to track sucrose preference, weight, activity, preference for high-fat food pellets vs. regular pellets, and running wheel activity. We also acquire continuous video recordings, which are processed with commercial software (HomeCageScan, Cleversys Inc.) to provide objective behavioral scoring. Finally, we have designed this system to work in conjunction with simultaneous brain electrophysiological recording. We are able to score electrophysiological data into wake/REM/nonREM states, as well as quantify spectral, LFP and spiking events. All of this data is recorded 24/7 for multiple weeks while discriminating behavior at sub-second resolution. Our results thus far demonstrate that sucrose preference in our system demonstrates response to both ambient lighting conditions and to acute stress. Ongoing work will quantify responses to chronic stress.