ADOLESCENT STRESS CONFERS RESILIENCE TO TRAUMATIC STRESS LATER IN LIFE: ROLE OF THE PREFRONTAL CORTEX

HERMAN, JAMES P.; COTELLA, EVELIN M.; NAWREEN, NAWSHABA

Granada

Congreso; IBRO 11th World Congress of Neuroscience; 2023

International Brain Organization (IBRO)

Adolescence is associated with terminal differentiation of neural pathways linked to emotional processing. Stress exposure impinges on ongoing developmental processes, in some cases predisposing stress-related pathologies, in others, resilience to later adversities. Here, we tested whether chronic stress exposure in adolescence would affect responses to a single prolonged stress (SPS) later in life, a manipulation linked to generation of PTSD-related symptoms. In these studies, male and female rats were exposed to chronic variable stress throughout late adolescence (d45-60), received SPS 5 weeks later, followed by assessment of emotional memory (contextual and cued fear conditioning) one week later. A separate group of animals was used to test the impact of the chronic stress-SPS model on prefrontal cortical electrophysiology. Our data indicated that SPS produced robust impairment of extinction learning in male rats, consistent with observations seen in PTSD. Reinstatement of freezing following a reminder shock was enhanced in males. Both effects were blocked by exposure to chronic stress in adolescence. Females had mild extinction impairments and reinstatement deficits, which were again blocked by adolescent stress. Behavioral effects of SPS effects were linked to reduced infralimbic (IL) cortex Fos staining in males, whereas in females, Fos staining was increased in central amygdala in females. Changes in Fos induction were prevented by adolescent stress, suggesting different neurocircuits involved in generating resilience in the two sexes. Finally, SPS caused marked decrements in infralimbic cortex excitability in males, an effect that was again blocked by adolescent stress exposure. Our data indicate that adolescent stress can impart resilience to the effects of traumatic stress on neuroplasticity and behavior in both males and females. These data suggest a possible mechanism affording behavioral resilience to traumatic stress in animals exposed to adversity in adolescence.