Impulsive Behavior
Conditions
Brief summary
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.
Detailed description
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.
Interventions
DEVICEAnodal tDCS
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.
DEVICESham tDCS
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.
Sponsors
Medical Research Council
University of Nottingham
Najat Khalifa
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Masking description
Participants will be randomly allocated, using a computer generated code, to receive either anodal tDCS or sham. For sham stimulation, 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
Intervention model description
Concurrent tDCS-MEG parallel arms single-blinded experimental design (right anodal v sham tDCS).
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* University students and staff * Aged 18-40
Exclusion criteria
* Individuals with epilepsy and other neurological conditions, history of significant head injury, substance misuse, major mental disorder and those receiving psychotropic medication. * Contraindications to use of Magnetic Resonance (pacemakers, metal implants, aneurysm clips) * Pregnancy.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Total number of correct anti-saccade (AS) trials | Change from baseline after 20 minutes of tDCS | A measure of rapid response impulsivity (inhibitory control) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Total number of correct pro-saccade (PS) trials | Change from baseline after 20 minutes of tDCS | A behavioral measure of rapid response impulsivity (inhibitory control) |
| Saccade latency for anti-saccade (AS) trials | Change from baseline after 20 minutes of tDCS | A behavioral measure of rapid response impulsivity (inhibitory control) |
| Total Scores on the UPPS+P Impulsive Behaviour Scale | Baseline | A self-report measure of impulsivity |
| Alpha and Beta band activity | Change from baseline after 20 minutes of tDCS | A Cortical measure of inhibitory control recorded using Magnetoencephalography (MEG). MEG is a brain imaging technique. |
| Saccade latency for pro-saccade (PS) trials | Change from baseline after 20 minutes of tDCS | A behavioral measure of rapid response impulsivity (inhibitory control) |
Other
| Measure | Time frame | Description |
|---|---|---|
| Alpha and Beta band activity | During 20 minutes of tDCS stimulation | Evaluation of mechanism of action of tDCS using MEG data |
Countries
United Kingdom
Outcome results
None listed