Mechanisms of Non-Invasive Neuromodulation Interventions: Influence on Human Neurochemistry and Functional Connectivity
Condition: Non-invasive Neuromodulation in Healthy Subjects
Study type: Interventional

Summary: 
      The aim of this project is to increase our understanding of how two different protocols of
      repetitive transcranial magnetic stimulation (rTMS), inhibitory (1 Hz) and excitatory (5 Hz),
      applied over the primary motor cortex of the presumed dominant hemisphere, affect functional
      connectivity and neurochemistry in the brain.
    

Detailed description: 
      Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation
      method which is effective for treating both psychiatric and non-psychiatric disorders, such
      as posttraumatic stress disorder, obsessive compulsive disorder, pain syndromes and for
      improving motor function in neurodegenerative diseases or following stroke. rTMS uses series
      of brief pulses of magnetic field applied to the surface of the head for a period of time
      (e.g. 20 minutes). The effects of rTMS are transient, and critically dependent upon the
      location, frequency and intensity of stimulation. Several studies have provided evidence that
      rTMS can influence the excitability and function of neurons (neuromodulation) for up to one
      hour, both near to, and distant from, the site of stimulation. However it is still unclear
      how these transient local and distant changes in function induced by specific rTMS protocols
      are mediated. In this project we will combine expertise in Magnetic Resonance Imaging (MRI),
      Magnetic Resonance Spectroscopy (MRS) and rTMS neuromodulation to develop and test protocols
      for examining the changes produced by non-invasive brain stimulation on healthy subjects.
      rTMS will be applied outside the scanner using standard TMS coils and MRI/S at 7 Tesla will
      be acquired before and immediately after rTMS. Our aim is to increase the understanding of
      how the two different rTMS protocols, inhibitory (1 Hz) and excitatory (5 Hz), applied over
      the primary motor cortex of the presumed dominant hemisphere, affect functional connectivity
      and neurochemistry in the brain.
    

Intervention name(s): Inhibitory rTMS (1 Hz); Excitatory rTMS (5 Hz)
Intervention type(s): Device; Device
Intervention description(s): Participants receive rTMS at a rate of 1 Hz, applied with a 70-mm figure-eight TMS coil connected to a stimulator, over the motor cortex hotspot contralateral to the dominant arm for 20 minutes at an intensity of 90% resting motor threshold (RMT) for a total of 600 TMS pulses. The total number of stimuli applied is well within the published safety guidelines for use of rTMS. rTMS is applied outside the scanner, whereas functional connectivity and neurochemistry are measured with MRI and MRS, respectively, at 7 Tesla. The MRI/MRS data are collected right before and immediately after the inhibitory rTMS intervention.; Participants receive rTMS at a rate of 5 Hz, applied with a 70-mm figure-eight TMS coil connected to a stimulator, over the motor cortex hotspot contralateral to the dominant arm for 20 minutes at an intensity of 90% RMT for a total of 600 TMS pulses. The total number of stimuli applied is well within the published safety guidelines for use of rTMS. rTMS is applied outside the scanner, whereas functional connectivity and neurochemistry are measured with MRI and MRS, respectively, at 7 Tesla. The MRI/MRS data are collected right before and immediately after the excitatory rTMS intervention.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: MRI; MRS; rTMS