Critical Period Plasticity is Associated with Resilience to Short Unpredictable Stress

Exposure to stress can increase the risk of depression in susceptible individuals, but not in resilient ones. Resilience to stress decreases with age, parallel to drastic changes in the quality of brain plasticity from juvenile to old age, suggesting that the type of plasticity found in the maturing brain promotes resilience. To indirectly test this, we administered short unpredictable stress to adult male and female mice, as well as to adolescent mice and mice that lack SynCAM 1 and display extended adolescent-like, critical period plasticity in the brain. We found that short unpredictable stress robustly increased core body temperature in all groups of mice, indicative of stress-induced hyperthermia (SIH) and confirming the efficacy of the stress paradigm. However, depressive-like behavior as measured though tail suspension test was increased in adult mice only, supporting that the type of plasticity found in the maturing brain promotes resilience to stress. All three groups of mice showed a mild increase in locomotor activity after stress, suggesting that the quality of plasticity does not correlate with resilience to anxiety-like phenotypes. Our study hence provides further evidence for the protective role of developmental plasticity during stress and points to new mechanisms that promote resilience to stress-induced depression.