Effects of Chronic Adolescent Cannabinoid Exposure on Decision-Making Under Uncertainty in Adulthood

Adolescence is characterized by increases in risk-taking across a range of behaviors, including experimentation with alcohol and illicit drugs. Cannabis is the most widely used illicit drug among adolescents, and increased use coincides with a period of marked brain development, particularly in the prefrontal cortex (PFC). PFC is important for decision-making processes, and exposure to cannabis during PFC development may lead to impairments in these processes, resulting in increased impulsivity and excessive risk-taking. The medial portion of prefrontal cortex (mPFC), continues to develop throughout adolescence, and is thought to be crucial is shifting behavior as rewards become uncertain or less valuable. In this study, we investigated the long-term effects of chronic adolescent cannabinoid exposure on risk deicison-making. 32 male and female Long Evans rats received i.p. injections of WIN 55, 212-2, a CB1 agonist, from postnatal day 30-60. Once animals reached adulthood, their risk-preference was measured using a gambling task. Rats chose between two levers, one of which paid a small, certain reward, and the other paid a larger, probabilistic reward. The probability of receiving the large reward varied randomly on each session, ranging from 16.7% to 66.7%. As rats performed this task, we used in vivo electrophysiology to record mPFC activity. Neural responses to cues and outcomes are compared across the range of probabilities between WIN-treated animals and controls.