Investigating Motor Cortex Processing for Pain Modulation
Condition: Motor Activity
Intervention: Motor Learning; Somatosensory Learning; Observational Task; Mental Imagery; transcranial direct current stimulation
Intervention description: Subject will have to draw a set of shapes and words during 20 minutes.; Subjects will perform a learning task involving sensory activation of the hand. The task will consist of learning letters of Braille.; Subjects will watch a 10 second video of a right-handed person performing movements of their left index finger. Subjects will be instructed to watch the video without any other specific instruction.; Subjects will be asked to perform mental imagery of motor practice - finger movements of the left hand for 10 minutes.; Subjects will undergo active and sham tDCS stimulation in a randomized and counterbalanced order. During both active and sham stimulation, we will use electrodes of 35cm^2, intensity of 2mA for a duration of 20 minutes. The anode electrode will be placed over the right primary motor cortex (M1) and the cathode will be placed over the contralateral supraorbital area. For active stimulation, the current will be on for the duration of 20 minutes. For sham stimulation, the current will ramp up, and then down again for 30 seconds to simulate the sensation of active tDCS.
Phase: Phase 1
Study type: Interventional
Primary purpose: Basic Science
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: There are 5 experiments: motor learning (3 groups, crossover), sensory learning (4 groups, parallel), observational task (2 groups, parallel), mental imagery (2 groups, parallel), and tDCS over the motor cortex (2 groups, crossover). Please note that the tDCS experiment has never been conducted.
Masking: Double (Investigator, Outcomes Assessor)
Enrollment: 115.0
Sex: Male
Minimum age: 18 Years
Maximum age: 64 Years
Healthy volunteers: Accepts Healthy Volunteers
Keywords: learning; pain perception

Summary:

      The purpose of this study is to investigate the effects of different types of interventions
      (motor learning, somatosensory learning, observation task, mental imagery and tDCS) on the
      perception of pain and motor cortex excitability in healthy male subjects. This is an
      exploratory study of healthy subjects only.
    

Eligibility criteria:

        Inclusion Criteria

          1. Provide informed consent to participate in the study

          2. 18 to 64 years old

          3. No presence of rheumatologic disease as self reported

          4. No clinically significant or unstable medical or psychiatric disorder as self reported

          5. No history of alcohol or substance abuse within the last 6 months as self reported

          6. No neuropsychiatric co-morbidity as self reported

          7. No Contraindications to single pulse TMS (TMS will be used to measure cortical
             excitability)

               -  history of seizures

               -  unexplained loss of consciousness

               -  metal in the head

               -  frequent or severe headaches or neck pain

               -  implanted brain medical devices

          8. No Contraindications to tDCS

               -  metal in the head

               -  implanted brain medical devices