Psilocybin treatment in rats performing a reversal learning task led to more rewards through increased task engagement, driven by changes in forgetting rates and reduced loss aversion. Computational modeling suggests psilocybin may induce an optimism bias by altering how beliefs are updated, which could have implications for clinical conditions marked by pessimism.
Rats treated with psilocybin achieved more rewards in a decision-making task, driven by increased task engagement, altered forgetting rates, and reduced loss aversion. Computational modeling of the rats' behavior revealed that psilocybin may induce an optimism bias through changes in how beliefs are updated. This finding has potential relevance for clinical populations characterized by a lack of optimism, such as those with depression.
A single dose of psilocybin (1.5 mg/kg) in female rats enhanced cognitive flexibility in several learning tasks by amplifying dopamine signals in the nucleus accumbens. The drug increased learning rates and reduced reliance on prior expectations, leading to faster reversal learning. However, calorie restriction and prior exposure to activity-based anorexia (ABA) reduced these benefits. Calorie restriction shifted the timing of psilocybin's effect on reversal learning and increased neural activity in the nucleus accumbens. Prior ABA exposure eliminated improvements in discrimination accuracy and trended toward worsening reversal learning, likely due to reduced cortical 5-HT2A receptor availability. The results show that nutritional state and history of anorexia-like behavior critically moderate psilocybin's cognitive effects.