Effect of lysergic acid diethylamide (LSD) on reinforcement learning in humans.
The non-selective serotonin 2A (5-HT Healthy volunteers received intravenous LSD (75 Raw data measures assessing sensitivity to immediate feedback (win-stay and lose-shift probabilities) were unaffected, whereas LSD increased the impact of the strength of initial learning on perseveration. Computational modelling revealed that the most pronounced effect of LSD was the enhancement of the reward learning rate. The punishment learning rate was also elevated. Stimulus stickiness was decreased by LSD, reflecting heightened exploration. Reinforcement sensitivity differed by phase. Increased RL rates suggest LSD induced a state of heightened plasticity. These results indicate a potential mechanism through which revision of maladaptive associations could occur in the clinical application of LSD.