Enhancing decision-making and cognitive impulse control with transcranial direct current stimulation (tDCS) applied over the orbitofrontal cortex (OFC): A randomized and sham-controlled exploratory study.
BACKGROUND
Decision-making and impulse control (both cognitive and motor) are complex interrelated processes which rely on a distributed neural network that includes multiple cortical and subcortical regions. Among them, the orbitofrontal cortex (OFC) seems to be particularly relevant as demonstrated by several neuropsychological and neuroimaging investigations.


METHODS
In the present study we assessed whether transcranial direct current stimulation (tDCS) applied bilaterally over the OFC is able to modulate decision-making and cognitive impulse control. More specifically, 45 healthy subjects were randomized to receive a single 30-min session of active or sham anodal tDCS (1.5 mA) applied over either the left or the right OFC (coupled with contralateral cathodal tDCS). They were also assessed pre- and post-tDCS with a battery of computerized tasks.


RESULTS
Our results show that participants who received active anodal tDCS (irrespective of laterality), vs. those who received sham tDCS, displayed more advantageous decision-making (i.e., increased Iowa Gambling Task "net scores" [p = 0.04]), as well as improved cognitive impulse control (i.e., decreased "interference" in the Stroop Word-Colour Task [p = 0.007]). However, we did not observe tDCS-related effects on mood (assessed by visual analogue scales), attentional levels (assessed by the Continuous Performance Task) or motor impulse control (assessed by the Stop-Signal Task).


CONCLUSIONS
Our study potentially serves as a key translational step towards the development of novel non-invasive neuromodulation-based therapeutic interventions directly targeting vulnerability factors for psychiatric conditions such as suicidal behaviour and addiction.
Neuromodulation Research Clinic, Douglas Mental Health University Institute, Montréal, Québec, Canada.
Julien
J
Ouellet
Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada.
Alexander
A
McGirr
Neuromodulation Research Clinic, Douglas Mental Health University Institute, Montréal, Québec, Canada.
Frederique
F
Van den Eynde
Depressive Disorders Program, Douglas Mental Health University Institute and McGill University, Montréal, Québec, Canada.
Fabrice
F
Jollant
Brain Imaging Group, Douglas Mental Health University Institute and McGill University, Montréal, Québec, Canada.
Martin
M
Lepage
Neuromodulation Research Clinic, Douglas Mental Health University Institute, Montréal, Québec, Canada; Depressive Disorders Program, Douglas Mental Health University Institute and McGill University, Montréal, Québec, Canada. Electronic address: nrc.douglas@me.com.
Marcelo T
MT
Berlim
D000328:Adult; D001288:Attention / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D003657:Decision Making / Q000502:physiology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D005715:Gambling / Q000503:physiopathology; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000502:physiology; D016037:Single-Blind Method; D065908:Transcranial Direct Current Stimulation / Q000379:methods; D055815:Young Adult
Decision-making; Impulse control; Neuromodulation; Orbitofrontal cortex; Transcranial direct current stimulation