REALITY MONITORING AND DOPAMINE
ConditionNeurosciences
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-45
SponsorHôpital le Vinatier
About this trial
Reality-monitoring characterizes the ability to determine whether information was perceived in the environment or only imagined . Impaired reality-monitoring abilities have been associated with hallucinations in patients with schizophrenia and patients with Parkinson's disease.
The investigators hypothesize a link between dopaminergic (DA) transmission and reality-monitoring.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Healthy volunteers who have given their written informed consent
Men and women from 18 to 45 years old
Normal or corrected vision
Being fluent in French or French for native language
Disqualifiers
Healthy volunteers who have given their written informed consent
Men and women from 18 to 45 years old
Normal or corrected vision
Being fluent in French or French for native language
Trial design
Design model
Crossover
Treatments tested in this trial
Précurseur de la dopamine
Other interventionIn the first condition, volunteers will receive a 100mg dose of L-dopa, 25mg dose of Aromatic amino acid decarboxylase inhibitors (Benserazide) and 10mg dose of Domperidone. In the second condition, volunteers will receive Sulpiride 800mg. In the third condition, volunteers will receive placebo Reality-monitoring performances will be evaluated with a standardized task. Working-memory will be evaluated with the n-back task. Self-monitoring performances will be observed during a speech production experiment in which speakers monitor their auditory feedback while speaking. Speech Bayesian reasoning: This task is a home-made task investigating the influence of prior on speech processing. Subjects will be required to identify speech in ambiguous auditory stimuli. Visual Bayesian reasoning: This task investigates the influence of prior on visual processing. Subjects will be required to recognize morph between faces and house.
antagoniste D2
Other interventionIn the second condition, volunteers will receive Sulpiride 800 mg
PLACEBO
Other interventionIn the third condition, volunteers will receive placebo
Treatment groups
39 Participants
are divided into 3 treatment groupsGroup A: Dopamine precursorActive comparator 1 intervention
Group B: D2 antagonistActive comparator 1 intervention
Group C: PLACEBOPlacebo comparator 1 intervention
Trial outcomes
Primary outcomes
1
Reality-monitoring performance
Measured with a behavioral task developed, validated and used in investigators lab. During the memory retrieval phase, 48 words will be presented, including the 32 words presented during encoding as well as 16 new words. Subjects will be required to identify whether each word was previously heard, imagined or new. Three words lists will be used and assigned randomly depending on the substance condition (L-dopa, Sulpiride, placebo). Each verbal list will include 16 items with the "imagine hear" encoding condition and 16 items with the "listen" encoding condition. A single measure including two variables of interest will account for the main evaluation criteria: * The average conditional source-identification measure (ACSIM) which represents the overall ability to correctly retrieve the source, conditional on that item was recognized as already presented. * The source misattributions,the number of confusions between heard and imagined events.
Time frame
One monthSecondary outcomes
1
Reaction times at the reality-monitoring task and scores of subjective confidence rating for reality-monitoring responses
Regarding reality-monitoring, a single test in which investigators will also measure the reaction times at the reality-monitoring task and scores of subjective confidence rating for reality-monitoring responses. The variable of interest will be the number of high-confident incorrect source-recognition responses. Investigators finally measure the vividness of each "imagined" or "listened" word with Visual Analogue Scales (VAS) from 0 to 100.
Time frame
One month2
Other cognitive tasks
In the same test investigators will measure the number of correct/incorrect responses and reaction times at the n-back working memory task. * The effect of dopamine modulation on the ability the ability to determine our speech as self-generated will be measured with a self-monitoring task. Investigators measure the magnitude of a voice peak response reflecting the feeling of agency. * The effect of dopamine modulation on perception will be evaluated with the performances measured during 2 home-made Bayesian reasoning tasks, evaluating speech processing and visual processing, respectively.
Time frame
One monthSponsors and contacts
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Source ClinicalTrials.gov