Here's how it works:
Research shows that when vibration is simultaneously applied as a counter- stimulation to an anesthetic injection, its sensation reaches the brain first, blocking the feeling of pain.
Proposed by Dr's Ronald Melzack and Patrick Wall in 1965, there is a neurological "gate" located within the dorsal horn of the spinal cord, that can either block pain signals, or permit them to travel up the spinothalamic tract to the brain.
The sensation (impulses) of vibration travels very quickly along thick, myelinated, A beta nerve fibers at 75 meters/second. In contrast, the sensation of pain travels slowly along thin, unmyelinated, C nerve fibers at 2 meters/second.**
When occurring at the same time, the sensation of vibration reaches the sensory area of the brain first, and also causes a release of inhibitory inter- neurons, preventing the activation of projection neurons at the synaptic junction in the dorsal horn of the spinal cord, resulting in a closure of the gate to the sensation of pain.Learn More