Alcohol or Stress Exposure During Late Adolescence Impairs Risk Assessment Later in Life, Disrupting the Ethological Structure of Behavior in Mice.

backgroundDecision-making relies on risk assessment as a critical process that enables organisms to evaluate threats before exploring potentially dangerous areas. While adolescence is a period of heightened vulnerability to external factors such as substance use and stress, it remains unclear how these factors disrupt risk assessment, particularly at the level of behavior structure: sequential actions, organization and transition probabilities between defensive and exploratory behaviors. We investigated whether repeated ethanol intoxication or pharmacological stress during late adolescence alters behavioral structure in early adulthood.

methodsMale and female C57BL/6 mice received four intermittent injections of saline, ethanol (4.0 g/kg), or the α2-adrenergic antagonist yohimbine (2.0 mg/kg) during late adolescence (7-8

resultsBoth ethanol and yohimbine produced persistent reductions in NoGo risk assessment behaviors in adulthood, in both sexes, with minimal effects on classical anxiety-like and exploratory measures. Transition probability and correlation analyses revealed a reorganization of behavioral structure, characterized by reduced transitions toward risk assessment events and a bias toward risk-taking actions.

conclusionsThese findings indicate that repeated late adolescent alcohol intoxication or stress exposure induces long-lasting alterations in risk assessment and decision-making strategies.