Pain
pain can be detected when nociceptors (pain receptors) discharge electrical impulses to the spinal cord and brain. These fire impulses outward, telling the muscles and body to react. These can be measured. Mountcastle, medical physiology, st. Louis: c.V. Mosby, pp. 391-427 "lip tactile response may be evoked by the end of the 7th week. At 11 weeks, the face and all parts of the upper and lower extremities are sensitive to touch. By 13 1/2 to 14 weeks, the entire body surface, except for the back and the top of the head, are sensitive to pain." s. Reinis & j. Goldman, the development of the brain c. Thomas pub., 1980
the fetus within this time frame of gestation, 20 weeks and beyond, is fully capable of experiencing pain. Without doubt a partial birth abortion is a dreadfully painful experience for any infant. R. White, dir. Neurosurgery & brain research, case western univ.
Also, "far from being less able to feel pain, such premature newborns may be more sensitive to pain"...That babies under 30 weeks have a "newly established pain system that is raw and unmodified at this tender age." p. Ranalli, neuro. Dept., univ. Of toronto