High Definition Transcranial Direct Current Stimulation Motor Cortex Versus Insula

The Effects of High Definition Transcranial Direct Current Stimulation Over Primary Motor Cortex Versus Insular Cortical Targets on Experimental Capsaicin Induced Hyperalgesia and Pain in Healthy Volunteers

Brain stimulation is a technique that can alter cortical function and thus be suitable for treating pain. This is especially when pain is chronic and associated with functional and even structural reorganization of the central nervous system. The idea of using invasive and noninvasive brain stimulation for pain relief is not new. Studies from the 1950s have investigated the brain stimulation for therapeutic use. Direct implantation of electrodes on the cerebral cortex has been carried out by Tsubokawa and colleagues in Japan. Although reported to be effective, it is invasive and involves the implantation of a foreign body into the cranium. Recent advancements in the techniques of non-invasive brain stimulation have improved and have measurable modulatory effects making this an attractive alternative for treating pain

Repetitive transcranial magnetic stimulation and transcranial direct current stimulation are currently the two main methods of non-invasive brain stimulation under investigation. Stimulation of the primary motor cortex has been reported to relieve neuropathic, musculoskeletal, visceral pain as well as headaches and migraine. Other parameters of stimulation have shown encouraging results. For example, stimulation of the secondary somatosensory cortex was also reported to relieve chronic visceral pain. However, there are numerous unanswered questions regarding these techniques.

This research project is an attempt to answer some of these questions:

1. Which pain conditions can be alleviated by non-invasive brain stimulation?

2. What are the best parameters for stimulation-

   1. method: transcranial direct current stimulation or repetitive transcranial magnetic stimulation transcranial or Alternating Current Stimulation
   2. High-Definition transcranial direct current stimulation or conventional transcranial direct current stimulation?
   3. which area to stimulate? Primary motor cortex, insula?

3. Will other forms of treatment such as pharmacotherapy, peripheral nerve stimulation or multi-disciplinary pain management enhance the effectiveness of non-invasive brain stimulation

Inclusion Criteria:

• Able to give informed consent to participate in the study.
• Male and female University Undergraduate, Postgraduate and staff in the Department of Psychology.
• American society of anesthesiology scores I to II patients.

Exclusion Criteria: the participant who has any history of:

• an adverse reaction to brain stimulation.
• a seizure
• an unexplained loss of consciousness
• a stroke
• serious head injury
• surgery to their head
• any brain related, neurological illnesses
• any illness that may have caused brain injury
• frequent or severe headaches
• metal in your head (outside the mouth) such as shrapnel, surgical clips, or fragments from welding
• any implanted medical devices such as cardiac pacemaker's or medical pumps
• taking any analgesic medications in the past 24 hours
• pregnancy
• anyone in your family has epilepsy