Pharmacological modulation of subliminal learning in Parkinson's and Tourette's syndromes.
Theories of instrumental learning aim to elucidate the mechanisms that integrate success and failure to improve future decisions. One computational solution consists of updating the value of choices in proportion to reward prediction errors, which are potentially encoded in dopamine signals. Accordingly, drugs that modulate dopamine transmission were shown to impact instrumental learning performance. However, whether these drugs act on conscious or subconscious learning processes remains unclear. To address this issue, we examined the effects of dopamine-related medications in a subliminal instrumental learning paradigm. To assess generality of dopamine implication, we tested both dopamine enhancers in Parkinson's disease (PD) and dopamine blockers in Tourette's syndrome (TS). During the task, patients had to learn from monetary outcomes the expected value of a risky choice. The different outcomes (rewards and punishments) were announced by visual cues, which were masked such that patients could not consciously perceive them. Boosting dopamine transmission in PD patients improved reward learning but worsened punishment avoidance. Conversely, blocking dopamine transmission in TS patients favored punishment avoidance but impaired reward seeking. These results thus extend previous findings in PD to subliminal situations and to another pathological condition, TS. More generally, they suggest that pharmacological manipulation of dopamine transmission can subconsciously drive us to either get more rewards or avoid more punishments.
Institut du Cerveau et de la Moëlle èpinière (CR-ICM), F-75013 Paris, France.
Stefano
S
Palminteri
Maël
M
Lebreton
Yulia
Y
Worbe
David
D
Grabli
Andreas
A
Hartmann
Mathias
M
Pessiglione
D000293:Adolescent; D000328:Adult; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D003463:Cues; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D005260:Female; D006801:Humans; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy / Q000503:physiopathology*; D010775:Photic Stimulation; D012201:Reward; D018967:Risperidone / Q000494:pharmacology; D013360:Subliminal Stimulation; D005879:Tourette Syndrome / Q000188:drug therapy / Q000503:physiopathology*
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D007980:Levodopa; D018967:Risperidone