The gate control theory of pain, proposed by Patrick David Wall and Ronald Melzack, postulates that nociception (pain) is "gated" by non-nociception stimuli such as vibration.
Pulsed radiofrequency, neuromodulation, direct introduction of medication and nerve ablation may be used to target either the tissue structures and organ/systems responsible for persistent nociception or the nociceptors from the structures implicated as the source of chronic pain.
Other uses of MAC include MAC-BAR (1.7-2.0 MAC), which is the concentration required to block autonomic reflexes to nociceptive stimuli, and MAC-awake (0.3-0.5 MAC), the concentration required to block voluntary reflexes and control perceptive awareness.
Between 1970 and 1973, his additional areas of research interest included cerebellar physiology, and from 1972 to 1981, receptor characteristics and central connections in fine muscle afferents, and in 2012, the neurophysiology of nociception and pain, especially in relation to joint pain.