Adolescent cannabinoid exposure left lasting marks on reward processing in the adult prefrontal cortex of rats

Adult rats that received WIN 55,212-2 during adolescence (postnatal days 30-60) showed subtle changes in choice behavior and significantly reduced mPFC neural activity during lever presses and reward delivery in a probabilistic reward task, suggesting impaired excitatory-inhibitory balance from adolescent exposure.

Male and female rats received daily WIN 55,212-2 or vehicle from postnatal day 30-60. In adulthood, animals performed a probabilistic reward choice task while mPFC neural activity was recorded electrophysiologically.

This provides direct neural evidence that adolescent cannabinoid exposure disrupts the prefrontal cortex's reward processing into adulthood, a mechanism that could underlie real-world difficulties with decision-making, motivation, and substance use vulnerability.

The prefrontal cortex is the last brain region to mature, not finishing until the mid-20s in humans. If adolescent cannabis exposure disrupts the excitatory-inhibitory balance during this critical maturation window, the effects on reward processing and decision-making could be permanent.

Used a synthetic cannabinoid (WIN 55,212-2), not THC or cannabis. Choice behavior effects were subtle. Only mPFC examined; other reward-related regions may also be affected. Rats received daily injections, which differs from typical human consumption patterns.