Dopamine, Transcranial Direct Current Stimulation
Conditions
Keywords
tDCS, Dopamine, PET
Brief summary
Transcranial direct current stimulation (tDCS) is a technique that is emerging as a prospective therapy for neurologic, psychiatric and addictive disorders. Specifically, anodal tDCS applied over the dorsolateral prefrontal cortex (DLPFC) is associated with improvement of cognitive functions and mood. Despite an increased use in clinical settings, tDCS suffers from limitations, especially regarding the strength and the duration of therapeutic effects. Strategies to optimize the conditions for tDCS application suffer from the lack of knowledge about its neurophysiological impact. Moreover, tDCS is increasingly used in private settings through commercial apparatus and tutorials to make a do-it-yourself device delivering tDCS now available on the Internet. This private use worries neuroscientists and health authorities. Even if the general impression is that, in controlled conditions, tDCS is safe with only mild and transient adverse effects, whether and how tDCS could be used for enhancing cognition in healthy subjects are needed to investigate in more detail. The investigators believe that a better understanding of some neurobiological effects of tDCS is crucial to further tailor tDCS for experimental and therapeutic applications and to define recommendations for a private use. As the cortex is densely connected with basal ganglia areas, including dopaminergic areas, tDCS is probably not only capable to target cortical but also subcortical structures remote from the stimulation sites. Some studies suggest that cortical stimulation by other approaches, such as transcranial magnetic stimulation (rTMS) leads to an increased dopaminergic transmission. The involvement of dopaminergic systems in tDCS effects has been investigated only indirectly in pharmacological studies. Thus, the direct effect of the DLPFC stimulation by tDCS on dopaminergic transmission is still unknown. The aim of this project is to reveal the online impact of a single-session of tDCS applied bilaterally over the DLPFC in healthy subjects on the dopaminergic transmission measured by PET, combined with the \[11C\]raclopride bolus-plus-continuous-infusion method.
Interventions
DEVICEProcedure: active tDCS
Intensity 2 mA during 20 minutes
DEVICEProcedure: sham tDCS
sham condition as delivered by the stimulator
Sponsors
Hôpital le Vinatier
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Non smoker * No pyschotrope consumption * No medical treatment * No psychiatric or somatic (neurological, endocrine, cardiac, renal) * Affiliated to the french social security
Exclusion criteria
* No consent * For females : Pregnant or without birth control * Contraindications to stimulation by tDCS or to an MRI exam * Being in an exclusion period or over the annual compensation ceiling * Participation in another study using ionizing radiation in less than a year
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in dopamine transmission after 1 session of 20min tDCS | during 100min of PET scan : Baseline (20-40min), during stimulation (40-60min) and after stimulation (60-80min & 80-100min) | Measure of the Binding Ratio defined as the ratio of : region of interest / cerebellum activities) |
Countries
France
Outcome results
None listed