Magnetic-evoked potentials (MEPs) are a type of neurophysiological test that is used to evaluate the function of the central nervous system. MEPs use a magnetic stimulator to deliver a brief, high-intensity magnetic pulse to a specific area of the brain or spinal cord. The resulting electrical activity is then recorded from electrodes placed on the scalp or muscles, providing information about the integrity and function of the motor pathways.

MEPs are commonly used in both clinical and research settings to assess a range of neurological conditions, including multiple sclerosis, stroke, spinal cord injury, and neuromuscular disorders. MEPs can help to identify areas of the brain or spinal cord that are affected by disease or injury, as well as monitor changes in function over time.

The magnetic stimulator used in MEP testing is similar to that used in transcranial magnetic stimulation (TMS), which is a technique that can be used to non-invasively stimulate the brain. However, while TMS is typically used to induce changes in brain activity that can be measured using techniques such as functional magnetic resonance imaging (fMRI), MEPs are focused specifically on the motor system.

During MEP testing, the magnetic pulse is typically delivered over the motor cortex, which is the part of the brain that controls voluntary movement. The resulting electrical activity is then recorded using surface electrodes placed on the scalp or muscles. The amplitude and latency of the resulting response can provide information about the integrity of the motor pathways, as well as the excitability of the neurons involved.

MEPs can be used to assess a range of motor functions, including muscle strength, reaction time, and coordination. They can also be used to monitor changes in function over time, making them a useful tool for tracking disease progression and treatment outcomes.

In addition to their clinical applications, MEPs are also widely used in neuroscience research. MEPs can be used to investigate the neural mechanisms underlying motor learning and plasticity, as well as to study the effects of drugs and other interventions on the motor system.

Overall, magnetic-evoked potentials are a valuable tool for assessing the function of the motor system in both clinical and research settings. By providing a non-invasive way to stimulate and measure neural activity, MEPs can help to identify areas of dysfunction and monitor changes in function over time. As technology continues to advance, it is likely that MEP testing will become even more widely used in the diagnosis and treatment of neurological disorders.