liikeärsykkeiden

Liikeärsykkeet, also known as motor evoked potentials (MEPs), are electrical signals recorded from muscles in response to transcranial magnetic stimulation (TMS) or electrical stimulation of the motor cortex. This technique is a non-invasive method used in neurophysiology to assess the integrity and function of the corticospinal tract, which connects the brain's motor areas to the spinal cord and then to the muscles.

The procedure involves applying a magnetic pulse or electrical current to a specific area of the scalp overlying the motor cortex. This stimulation generates an electrical impulse that travels down the corticospinal tract. If the pathway is intact, the impulse will reach the target muscle, causing a brief, involuntary contraction. This contraction generates an electrical potential that is detected by electrodes placed on the muscle's surface.

The amplitude and latency of the MEP provide valuable information. A reduced amplitude can indicate damage or dysfunction within the motor pathway, such as in stroke, multiple sclerosis, or spinal cord injury. A prolonged latency suggests a slower conduction velocity along the corticospinal tract, which can also be indicative of neurological disease. Conversely, normal MEPs suggest that the motor pathway is functioning properly.

Liikeärsykkeitä are employed in clinical settings for diagnosing and monitoring neurological conditions affecting motor control, as well as in research to understand brain plasticity and motor learning. The interpretation of MEPs is typically done in conjunction with other clinical findings and neurophysiological tests.