Increases Endurance by 1. This implant can be bought from Dr. Usanagi at the New Vegas medical clinic who describes the implant as a change to the cardiovascular system. Despite its advertised effect, it is not taken into account when Endurance is counted for the maximum implant limit. Only using the Intense Training perk to increase Endurance, or by using the +1 SPECIAL point you will get for completing Lonesome Road The Bear-Slayer, Dead Man's Burden, Divide Survivor, or Scourge of the East to increase Endurance will allow purchasing additional implants.
Behind the scenes
The name "Nociception Regulator" refers to the function of nociceptors, sensory receptors in the body that detect potentially damaging stimuli (such as excess pressure or heat) and send the nerve signals to the brain and spinal cord. This process is largely responsible for perceiving pain.