Dynamic Resilience: Stress Phenotypes and Their Impact on Opioid-Taking Behavior, Brain Activity, and Gene Expression

However, by three weeks, intake in resilient mice returned to baseline levels, while intake in susceptible mice remained elevated. To examine neural correlates of these behavioral shifts, we measured cFOS activity in the basolateral amygdala (BLA) and nucleus accumbens (NAc). In susceptible mice, BLA cFOS remained elevated at both time points.

NAc activity was elevated in both groups at one week but normalized in resilient mice by three weeks. This pattern paralleled opioid intake behavior. Additionally, we found distinct gene expression changes that may underlie the adaptive shifts seen in resilient mice.

These findings underscore that resilience is a dynamic process characterized by evolving behavioral and neural responses. By evaluating multiple time points, our research provides new insights into how different stress phenotypes influence opioid use trajectories and highlights critical brain regions involved in these processes.