Descending Inhibitory Controls
Part of Buzzy’s efficacy, and the reason it can help even when distant from the site of procedural pain, is something called Descending Noxious Inhibitory Control, or DNIC. While Gate Control happens locally, (confusing nerves right where the pain happens) another effective mechanism of pain control uses the brain’s ability to dampen out unwanted signals. DNIC can be triggered with intense sensations synergtistically with cold, ramping up C-fiber intensity. Instead of happening right where the nerves are, though, an almost unpleasant degree of cold can work anywhere on the body.
The idea is like putting your hand in a bucket of ice water. Whoa, it’s cold! But you can handle the amount of cold initially. Studies have found that when someone’s hand is in ice water, they can handle more intense pain everywhere else in the body, probably because the sensation of ice is so intense it doesn’t leave as much room for the brain to notice pain as sharply other places. In scientific terms, intense cold activates a supraspinal moducation raising the body’s overall pain threshold. This diagram shows how the body dampens pain signals. The concept is that the body learns to dampen continued pain, but dampening occurs everywhere in the body, not just at the exact site of pain. Cause a pseudo-pain with cold, and the body will dampen all kinds of pain, everywhere.
Vibration also likely uses some degree of descending inhibitory control, taking up sensory bandwidth and striving to decrease the intensity of the sensations.