Chronic Social Defeat Stress

Chronic social defeat stress (CSDS) is a widely used model for depression and anxiety-like behavior in which a subject mouse is repeatedly exposed to a larger, aggressive resident mouse (typically a retired CD-1 breeder) over 10 consecutive days. Each defeat session involves brief physical subordination (5-10 minutes of attack), followed by 24 hours of sensory contact through a perforated divider in the aggressor's home cage. This produces robust, lasting behavioral changes including social avoidance, anhedonia, and anxiety.

A critical feature of the CSDS model is that approximately 30-50% of defeated mice show resilience — they maintain social interaction despite the stress exposure — enabling stratification into susceptible and resilient phenotypes. The social interaction test conducted 24 hours after the last defeat session serves as the primary phenotypic readout: susceptible mice avoid the interaction zone when an aggressor is present, while resilient mice show normal social approach. This individual variation makes CSDS uniquely valuable for studying the neurobiology of stress vulnerability versus resilience.

ConductMaze automates the post-defeat social interaction assessment: it tracks the subject's position relative to a wire-mesh enclosure (containing the aggressor or empty), computes time in the interaction zone and corner zones, and generates the social interaction ratio that defines susceptible versus resilient phenotypes. The software also manages the 10-day defeat schedule and randomizes aggressor assignments.