9: Substantial evidence indicates that structures used for pain processing in early development differ from those of adults, using different neural elements available at specific times during development, such as the subcortical plate, to fulfill the role of pain processing.
1. Anand, 2006, p.3, col.1, para.5, “Clinical and animal research shows that the fetus or neonate is not a ‘little adult,’ that the structures used for pain processing in early development are unique and different from those of adults, and that many of these fetal structures and mechanisms are not maintained beyond specific periods of early development. The immature pain system thus uses the neural elements available during each stage of development to carry out its signaling role.”
Anand KJS. Fetal Pain? Pain: Clinical Updates. 14:2 (2006) 1-4.
2. Van Sheltema, 2008, p.313, para.1; “[P]ain perception during fetal and neonatal development does not necessarily involve the same structures involved in pain processing as those in adults, meaning that the lack of development of certain connections is not sufficient to support the argument that fetuses can not feel pain until late gestation.10 Some say even that the structures used for pain processing in the fetus are completely different from those used by adults and that many of these structures are not maintained beyond specific periods of early development.8,15”
Van Scheltema PNA, Bakker S, Vandenbussche FPHA, Oepkes, D. Fetal Pain. Fetal and Maternal Medicine Review. 19:4 (2008) 311-324.
10 Lee SJ, Ralston HJP, Drey EA, Partridge, JC, Rosen, MA. A Systematic Multidisciplinary Review of the Evidence. Journal of the American Medical Association. 294:8 (2005) 947-954.
8Fitzgerald M. The Development of Nociceptive Circuits. Nature Reviews: Neuroscience. 6 (2005) 507-520.
15White, MC, Wolf, AR. Pain and Stress in the Human Fetus. Best Practice & Research Clinical Anaesthesiology. 18 (2004) 205-220.
3. White, 2004, p.208, para.4, “The anatomical evidence shows that the nociceptive connections of the fetus are not merely immature versions of the adult but are structurally different and these differences confer differences in function. Furthermore, interference with the natural progression to adult-like status can have extensive effects. Nerve section of afferent pathways, from the forelimb in the rat during early development, results in major changes in the subsequent central connections and sensory perception from other sites.40 Clearly this has implications for any form of fetal surgery.”
White, MC, Wolf, AR. Pain and Stress in the Human Fetus. Best Practice & Research Clinical Anaesthesiology. 18 (2004) 205-220.
40Killackey HP & Dawson DR. Expansion of the central hindpaw representation following fetal forelimb removal in the rat. European Journal of Neuroscience 1 (1989) 210-221.
4. Fitzgerald, 2005, p.507, col.1, para.2, “Newborn infants show strong pain behaviour, but the study of the development of nociceptive pathways shows that their pain involves functional signaling pathways that are not found in the mature nervous system in healthy individuals.”
Fitzgerald M. “The Development of Nociceptive Circuits.”Nature Reviews: Neuroscience. 6 (2005) 507-520.
5. O’Donnell, 2008, page 60, “Lee et al.15 have stated that the capacity “for conscious perception of pain can arise only after thalamocortical pathways begin to function, which may occur in the third trimester around 29-30 weeks’ gestational age.” As discussed above, given the limitations of our current knowledge, this is unduly definite. Pain perception in the fetus may not use the same pathways as in the human adult, just as it may not in other species, such as the octopus10. Many fetal structures are different from those in the adult, and may function in a different way. We do not know that in the fetus thalamocortical pathways are essential for any perception of pain. Connections from the thalamus to the subplate zone may be sufficient, for example. If Lee et al.’s reasoning were correct, it would imply that the majority of premature babies in intensive care do not feel pain either.”
K O’Donnell & V. Glover, “New Insights into Prenatal Stress: Immediate and Long-term Effects on the Fetus and Their Timing,” in Neonatal Pain, ed. Giuseppe Buonocore & Carlo V. Bellieni (Milan: Springer, 2008), 60.
15 Lee SJ, Ralston HJ, Drey EA et al, Fetal pain: a systematic multidisciplinary review of the evidence. Journal Amer. Med Assoc. 294 (2005) 947–54.
10 Edelman DB, Baars BJ, Seth AK, Identifying hallmarks of consciousness in non-mammalian species. Conscious Cogn. 14 (2005) 169–87.