<prompt> Transcutaneous electrical nerve stimulation is based onAllodyniaReferred painCentral Pain.Gate control theory of pain  <response>: Ans. d Gate control theory of painRef: Ganong, 25th edp.172Gate control theory of pain:Proposed by Melzack and WallDorsal horn neuron receives collaterals from both the touch receptors and pain receptors. Simultaneous activation of innocuous touch receptors reduces the responsiveness of dorsal horn neurons to their input from pain receptor afferentsIt is also the basis behind transcutaneous electrical nerve stimulation TENS where in electrodes are used to activate Aa and Ab fibers near the site of injury to relieve pain 