|Transcranial Magnetic Stimulation (TMS) is a non-invasive technique used to
stimulate the human brain. It was invented in 1985 and has since been
used extensively for research and clinical purposes.
When you see a picture, hear a sound, or think of
something, electric currents will flow inside certain parts of your
brain. TMS causes similar electric currents in the brain, but the neurons
are instead activated with a magnetic pulse from a coil that is placed
over the head.
The neurons act as antennae that pick up the signal from the coil. Electromagnetic
fields travel effortlessly through the scalp and skull, which allows TMS
easy and non-invasive access to the brain.
TMS has a unique role in understanding how the brain works. Brain imaging
techniques such as
electroencephalography (EEG), magnetoencephalography (MEG), and functional
magnetic resonance imaging (fMRI) record brain activity and can tell us
where and when the activations occurred. However, they cannot tell if a
specific activation is necessary for a given task. TMS can be used for
turning a specific brain area "off" for a small fraction of as second.
Therefore, TMS allows establishing causality between brain activations
and different types of sensory, motor, and cognitive
TMS may also be useful for diagnosis and treatment of some clinical
conditions, such as migraine headache and depression, and for pre-surgical
mapping of motor functions.
The effects of TMS depend on which brain area is stimulated. Therefore,
TMS is often combined with navigation devices that allow accurate
localization of the stimulated area. TMS is also typically done with
electromyogram (EMG) that measures electrical activity of muscles, and
behavioral measurements such as reaction times. Finally, to observe the
effects of TMS directly on the brain we may also record EEG, fMRI, or PET
simultaneously with TMS. Such multi-modal combinations of techniques are powerful in studying how the brain works in health and in
Our TMS laboratory is equipped with two MagPro X100 with MagOption stimulators, multiple MagPro (including MRI-compatible and liquid-cooled) coils, a Nexstim eXimia Navigated Brain Stimulation (NBS) frameless neuronavigator integrated with a 6-channel EMG unit, and a Nexstim eXimia 60-channel EEG system. To ensure exceptionally
clean EEG recordings, the instruments are located within an electrically
shielded room. Computer-controlled visual,
auditory, and somatosensory stimulation systems as well as behavioral
response monitoring are available in the laboratory. Our analysis
software allows integration of TMS, EEG, MEG, anatomical MRI, and
fMRI data. The TMS laboratory is located inside the Biomedical Imaging Core (BIC) at the Martinos Center that is ideally equipped to support clinical and pharmacological studies and experiments that require advanced physiological monitoring.
You can learn more about TMS here.
You may also be interested in seeing the TMS Wiki page here.