This study aims to use concurrent Transcranial Direct Current Stimulation (tDCS) and Magnetoencephalography (MEG) with measures of impulsivity to examine the neurobiological underpinnings of rapid response impulsivity (RRI) and how these can be modified using tDCS in healthy subjects.
Concurrent tDCS-MEG parallel arms single-blinded experimental design (right anodal v sham tDCS) will be employed in this study. The study will be conducted at the University of Nottingham, using a sample of student volunteers. This study aims to examine the influence of anodal tDCS on beta-band and alpha-band oscillatory activities, using an anti-saccade task administered before, during and after tDCS stimulation. It can potentially help understand the neurobiological mechanisms underpinning rapid response impulsivity and how these can be influenced by tDCS. The research hypotheses are that (i) a generalised mechanism for top-down inhibitory control will play a vital role, whereby prefrontal beta-band activity initiates alpha-band activity for functional inhibition over the frontal eye fields and other areas in the neurocircuitry involved in RRI; (ii) anodal tDCS (as opposed to sham) delivered over the right DLPFC will enhance this mechanism; and (iii) there will be no significant correlations between measures of self-report impulsivity and performance on the anti-saccade task and measures of oscillatory activity.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
36
The experimental condition will use a constant current of 2mA for 20 minutes, delivered via gradual increase and decrease over 10 seconds at the onset and offset of stimulation (current ramps), respectively.
The anodal electrode will be placed over the supreorbital ridge. The current will be delivered only in the first 10 seconds, after which the stimulation will cease but with the electrodes still in place throughout the session. The session will last for 20 minutes.
University of Nottingham
Nottingham, Notts, United Kingdom
Total number of correct anti-saccade (AS) trials
A measure of rapid response impulsivity (inhibitory control)
Time frame: Change from baseline after 20 minutes of tDCS
Total number of correct pro-saccade (PS) trials
A behavioral measure of rapid response impulsivity (inhibitory control)
Time frame: Change from baseline after 20 minutes of tDCS
Saccade latency for anti-saccade (AS) trials
A behavioral measure of rapid response impulsivity (inhibitory control)
Time frame: Change from baseline after 20 minutes of tDCS
Saccade latency for pro-saccade (PS) trials
A behavioral measure of rapid response impulsivity (inhibitory control)
Time frame: Change from baseline after 20 minutes of tDCS
Total Scores on the UPPS+P Impulsive Behaviour Scale
A self-report measure of impulsivity
Time frame: Baseline
Alpha and Beta band activity
A Cortical measure of inhibitory control recorded using Magnetoencephalography (MEG). MEG is a brain imaging technique.
Time frame: Change from baseline after 20 minutes of tDCS
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