Methods to Enhance Transcranial Direct Stimulation (tDCS)
Condition: Healthy Volunteers; Brain Excitation
Study type: Interventional

Summary: 
      tDCS has been shown to be an effective treatment for depression. However, tDCS is a
      relatively new clinical tool and more needs to be understood about its use. This study hopes
      to further the field of knowledge by examining how tDCS should be optimally used. Application
      of tDCS in clinical trials of depression is typically to the prefrontal cortex, but in this
      project, tDCS application will be to the motor cortex as it provides a more ready measure of
      excitability. Excitability will be measured using Transcranial Magnetic Stimulation (TMS) to
      the motor cortex and electromyography (EMG) recordings from peripheral muscles stimulated.
      Using a cross-over three-arm design this study aims to investigate whether daily tDCS
      administered in increasing intensity across sessions leads to greater and lasting effects on
      brain excitability than keeping the intensity at a same dose across the days and whether the
      excitatory effect could be enhanced with D-cycloserine, a medication known to prolong the
      excitatory effects of a single session of tDCS. This in turn will inform on how to optimize
      tDCS for therapeutic applications, e.g treatment of depression. The study hypothesis is that
      5 sessions of tDCS with a dose of D-cycloserine given on the Monday and Thursday sessions
      will result in more sustained effect on motor cortex excitability than 5 sessions of tDCS
      alone. The second hypothesis is that the gradational increases in tDCS intensity over 5
      sessions will result in greater motor cortex excitability than 5 sessions of tDCS where
      intensity is kept constant across sessions.
    


Intervention name(s): Transcranial Direct Current Stimulation (tDCS); Transcranial Direct Current Stimulation (tDCS); Transcranial direct Stimulation (tDCS) and D-cycloserine
Intervention type(s): Device; Device; Other
Intervention description(s): tDCS applied to to motor cortex every weekday (5 sessions), at 2mA ,during 20 minutes.Conductive rubber electrodes (7 x 5 cm = 35 cm2) covered by sponges soaked in saline will be used, held in place by a band. The current will be gradually increased to the level of 2 mA over 30 seconds (to avoid the sensation of a flash).; tDCS applied to the motor cortex every day of the week during 20 minutes, at 1mA first session, 1.5 mA second and third sessions, and 2mA fourth and fifth sessions, during 20 minutes. Conductive rubber electrodes (7 x 5 cm = 35 cm2) covered by sponges soaked in saline will be used, held in place by a band. The current will be gradually increased over 30 seconds (to avoid the sensation of a flash).; Transcranial Direct Stimulation applied to the motor cortex every day of the week (5 sessions) at 2mA, during 20 minutes. Conductive rubber electrodes (7 x 5 cm = 35 cm2) covered by sponges soaked in saline will be used, held in place by a band. The current will be gradually increased to the level of 2 mA over 30 seconds (to avoid the sensation of a flash).
D-cycloserine, administered orally (capsules), 100 mg, twice a week (Monday and Thursday), prior to the tDCS session.
Other intervention name(s): tDCS (Eldith DC-Stimulator (CE certified); Eldith DC-Stimulator (CE certified); tDCS - Eldith DC-Stimulator (CE certified); D-cycloserine, Seromycin Pulvules, 100 mg
Intervention MeSH terms: Cycloserine
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Keywords: Brain excitation; transcranial Direct Stimulation; administration pattern