Effects On The Brain
The exact details of how TMS functions are still being explored. The effects of TMS can be divided into two types depending on the mode of stimulation:
- Single or paired pulse TMS causes neurons in the neocortex under the site of stimulation to depolarize and discharge an action potential. If used in the primary motor cortex, it produces muscle activity referred to as a motor evoked potential (MEP) which can be recorded on electromyography. If used on the occipital cortex, 'phosphenes' (flashes of light) might be perceived by the subject. In most other areas of the cortex, the participant does not consciously experience any effect, but his or her behaviour may be slightly altered (e.g. slower reaction time on a cognitive task), or changes in brain activity may be detected using sensing equipment.
- Repetitive TMS produces longer-lasting effects which persist past the initial period of stimulation. rTMS can increase or decrease the excitability of the corticospinal tract depending on the intensity of stimulation, coil orientation and frequency. The mechanism of these effects is not clear although it is widely believed to reflect changes in synaptic efficacy akin to long-term potentiation (LTP) and long-term depression (LTD).
Read more about this topic: Transcranial Magnetic Stimulation
Famous quotes containing the words effects and/or brain:
“Like the effects of industrial pollution ... the AIDS crisis is evidence of a world in which nothing important is regional, local, limited; in which everything that can circulate does, and every problem is, or is destined to become, worldwide.”
—Susan Sontag (b. 1933)
“I think taste is a social concept and not an artistic one. Im willing to show good taste, if I can, in somebody elses living room, but our reading life is too short for a writer to be in any way polite. Since his words enter into anothers brain in silence and intimacy, he should be as honest and explicit as we are with ourselves.”
—John Updike (b. 1932)