During these two procedures, the volunteers underwent brain scans to see what, if any, effect there was in the brain.

The team, including leading scientists from University College London, Southampton University and the University of York, found the superficial needling resulted in activation of the motor areas of the cortex, a normal reaction to pain.

But with deep needling, the limbic system, part of the pain matrix, is deactivated.

The finding was surprising because experts had always assumed acupuncture activates the brain in someway.

It has been known that when opposite surfaces in the nasal cavity touch and press against each other they stimulate one of the main nerves in the face called the trigeminal nerve; which in turn causes secretion of a special substance that is irritant to the nasal tissue.

When this occurs it has known in certain instances to confuse the brain into interpreting the stimulation as a headache - a phenomenon known as referred pain.

The researchers evaluated 21 patients who had severe migraines that had not responded to conventional treatment.

CT scans of the sinuses revealed that these 21 patients had intranasal contact points.