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6: Documentation

6: The position, asserted by some medical experts, that the unborn child is incapable of experiencing pain until a point later in pregnancy than 20 weeks after fertilization predominately rests on the assumption that the ability to experience pain depends on the cerebral cortex and requires nerve connections between the thalamus and the cortex. However, recent medical research and analysis, especially since 2007, provides strong evidence for the conclusion that a functioning cortex is not necessary to experience pain.

DOCUMENTATION:

a. The position, asserted by some medical experts, that the unborn child is incapable of experiencing pain until a point later in pregnancy than 20 weeks after fertilization predominately rests on the assumption that the ability to experience pain depends on the cerebral cortex and requires nerve connections between the thalamus and the cortex.

1. Anand, 2006, p.3, col.1, para.4 – col.2, para.2, “[R]ecent reviews purporting to rule out the occurrence of fetal pain.3,4,22… presuppose that cortical activation is necessary for fetal pain perception.3,4,22 Based upon this assumption, the lack of evidence for pain-specific thalamocortical connections support their contention against fetal pain.”

Anand KJS.  Fetal Pain?  Pain: Clinical Updates. 14:2 (2006) 1-4.

3 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.

4 Mellor DJ, Diesch TJ, Gunn AJ, Bennet L. The importance of ‘awareness’ for understanding fetal pain. Brain Research Reviews.  49 (2005) 455-471.

22Derbyshire SWG. Can fetuses feel pain? British Medical Journal.  332 (2006) 909-912.

2. Royal College of Obstetricians & Gynecologists, 2010, Summary, para.2, “In reviewing the neuroanatomical and physiological evidence in the fetus, it was apparent that connections from the periphery to the cortex are not intact before 24 weeks of gestation and, as most neuroscientists believe that the cortex is necessary for pain perception, it can be concluded that the fetus cannot experience pain in any sense prior to this gestation.”

Fetal Awareness: Review of Research and Recommendations for Practice.  Report of a Working Party.  Royal College of Obstetricians and Gynecologists. March 2010.

3. Lee, 2005, Abstract, para.3, “Pain perception requires conscious recognition or awareness of a noxious stimulus.  Neither withdrawal reflexes nor hormonal stress response to invasive procedures prove the existence of fetal pain, because they can be elicited by nonpainful stimuli and occur without conscious cortical processing.  Fetal awareness of noxious stimuli requires functional thalamocortical connections.  Thalamocortical fibers begin appearing between 23 to 30 weeks’ gestational age, while eletroencephalography suggests the capacity for functional pain perception in preterm neonates probably does not exist before 29 or 30 weeks.”

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.

4. Brusseau, 2006, p.190, col.2, para.4, “… such reflex responses to noxious stimuli have not been shown to involve the cortex and, thus, traditionally have not been thought to be available to conscious perception.”

Brusseau R, Myers L.  Developing consciousness: fetal anesthesia and analgesia.  Seminars in Anesthesia, Perioperative Medicine and Pain. 25 (2006) 189-195.

5. Mellor, 2005, p.464, col.2, para.4, “[D]espite the presence of intact nociceptive pathways from around mid-gestation, the critical aspect of cortical awareness in the process of pain perception is missing.”

Mellor DJ, Diesch TJ, Gunn AJ, Bennet L. The importance of ‘awareness’ for understanding fetal pain. Brain Research Reviews.  49 (2005) 455-471.

6. Derbyshire, 2006, p.910, col.1, para.2, “Current theories of pain consider an intact cortical system to be both necessary and sufficient for pain experience.9,10

Derbyshire SWG. Can fetuses feel pain? British Medical Journal.  332 (2006) 909-912.

9Coghill RC, McHaffie JC, Yen YF. Neural correlates of interindividual difference in the subjective experience of pain. Procedings of the National Academy of Science of the United States of America. 100 (2003) 8538-8542.

10Derbyshire SWG, Whalley MG, Stenger VA, Oakley DA. Cerebral activation during hypnotically induced and imagined pain. Neuroimage.  23 (2004) 392-401.

7.Derbyshire, 2010, “Although there is a general consensus that certain cortical structures are necessary for pain, legitimate arguments that cortical structures are not necessary continue to be raised.9,11,12”

Derbyshire SW, Foetal pain? Best Practice & Research Clinical Obstetrics and Gynaecology 24:5 (2010) 647-655.

9Lowery CL, Hardman MP, Manning N et al. Neurodevelopmental changes of fetal pain. Sem Perinatol, 2007; 31: 275–282.

11Anand KJS. Consciousness, cortical function, and pain perception in non-verbal humans. Behav Brain Sci. 2007; 30: 82–83.

12Merker B. Consciousness without a cerebral cortex: a challenge for neuroscience and medicine. Behav Brain Sci. 2007; 30:63–81.

b. However, recent medical research and analysis, especially since 2007, provides strong evidence for the conclusion that a functioning cortex is not necessary to experience pain.

1. Merker, 2007, p.80, col.2, para.3, “The evidence and functional arguments reviewed in this article are not easily reconciled with an exclusive identification of the cerebral cortex as the medium of conscious function… The tacit consensus concerning the cerebral cortex as the ‘organ of consciousness’ would thus have been reached prematurely, and may in fact be seriously in error.”

Merker B. Consciousness without a cerebral cortex: A challenge for neuroscience and medicine. Behavioral and Brain Sciences. 30 (2007) 63-81.

2. Anand, 2007, p.82, col.2, para.1, “A reappraisal of the mechanisms of huan consciousness, differentiating it from its attributes, functions, or contents, is long overdue.  Widely held concepts about the key mechanisms of consciousness, or its fullest expression via the human brain, have not been reexamined in the light of accumulating evidence since the 1970’s.  Merker presents the organization of a subcortical system…with multiple lines of anatomical, neurophysiological, behavioral, clinical, andneuropathological evidence, and a teleological rationale – all of which support a persuasive argument for the subcortical control and temporal sequencing of behavior.… One distressing impact of associating consciousness with cortical function, briefly mentioned by Merker in section 6 of the target article, pertains to the mistaken notions regarding pain perception in patient populations with impaired cortical function or cortical immaturity.”

Anand KJS.  Consciousness, cortical function, and pain perception in nonverbal humans. Behavioral and Brain Sciences.  30:1 (2007) 82-83.

3. Anand, 2006, p.2, col.2, para.5, “Multiple lines of evidence thus corroborate that the key mechanisms of consciousness or conscious sensory perception are not dependent on cortical activity:”

col.1, para.4, “Penfield and Jasper proposed that ‘the highest integrative functions of the brain are not completed at the cortical level, but in a system of highly convergent subcortical structures supplying the key mechanism of consciousness.’”

col.2, para.3, “Further clinical evidence for conscious perception mediated by subcortical centers comes from infants and children with hydranencephaly.12,13

col.2, para.4, “Thus, a subcortical system… mediates the organization of consciousness.15… That intact forebrain commissures are not required for high levels of cognitive function16 provides further evidence for the subcortical integration…”

“Whether consciousness is required for sensory perception has also been questioned by recent studies of adult patients in a persistent vegetative state.17,18

p.3, col.1, para.4 – col.2, para.2, “[R]ecent reviews purporting to rule out the occurrence of fetal pain.3,4,22… presuppose that cortical activation is necessary for fetal pain perception.3,4,22 Based upon this assumption, the lack of evidence for pain-specific thalamocortical connections support their contention against fetal pain.  This line of reasoning, however, ignores clinical data cited above that ablation or stimulation of the primary somatosensory cortex does not alter pain perception in adults, whereas thalamic ablation or stimulation does.  The thalamus plays a pivotal role in regulating the spinal-brainstem-spinal loops that mediate context-dependent descending facilitation or inhibition, coordinated via the key mechanisms underlying consciousness.”

Anand KJS. Fetal Pain? Pain: Clinical Updates. 14 (2006) 1-4.

Penfield W, Jasper HH.  Epilepsy and the Functional Anatomy of the Human Brain. Boston: Little, Brown & Co; 1954.

3Lee 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.

4 Mellor DJ, Diesch TJ, Gunn AJ, Bennet L. The importance of ‘awareness’ for understanding fetal pain. Brain Research Reviews.  49 (2005) 455-471.

12Marin-Padilla M. Developmental neuropathology and impact of perinatal brain damage.  Journal of Neuropathology & Experimental Neurology. 56 (1997) 219-235.

13Takada K, Shiota M, Ando M, et al. Porencephaly and hydranencephaly: a neuropathological study of four autopsy cases. Brain Development. 11 (1989) 51-56.

15 Merker B. Consciousness without a cerebral cortex: A challenge for neuroscience and medicine. Behavioral and Brain Sciences. 30 (2007) 63-81.  [in press at time of citation by Anand]

16LeDoux JE, Risse GL, Springer SP, Wilson DH, Gazzaniga. Cognition and Commissurotomy. Brain. 100 (1997) 87-104.

17Shewmon DA. A critical analysis of conceptual domains of the vegetative state: sorting fact from fancy. Neurorehabilitation. 19 (2004) 364-374.

18Schiff NDM.  Neurology. 64 (2005) 514-523.

22Derbyshire SWG. Can fetuses feel pain? British Medical Journal.  332 (2006) 909-912.

4. Brusseau, 2008, p.16, para.1, However, if one were to argue that a minimal form of consciousness might be possible without cortical involvement, then certainly one would have to consider thalamic development as a benchmark for the possible generation of such a state.  As described above, thalamic structures seem to be in place somewhere between 20 and 30 weeks… Other evidence, however, points to a much earlier maturation of thalamic processing function.  Thalamic connections are intimately involved in the generation of the physiochemical and endocrine responses to nociception that are seen as early as 18 weeks.20,27

p.20, para.3, “Perhaps the subcortex is necessary and sufficient for at least a minimal, Hameroffian consciousness, one that (if the data regarding anencephalic children are to be believed) may render an integrated experience of nociception that we might call pain.”

Brusseau R.  Developmental Perpectives: is the Fetus Conscious?  International Anesthesiology Clinics. 46:3 (2008) 11-23.

20Teixeira Jm, Glover V, Fisk NM. Acute cerebral redistribution in response to invasive procedure in the human fetus.  American Journal of Obstetrics & Gynecology. 181 (1999) 1018-1025.

27Gitau R, Fisk NM, Teixeira JM, Cameron A, Glover V. Fetal hypothalamic–pituitary–adrenal stress responses to invasive procedures are independent of maternal responses.  Journal of Clinical Endocrinology and Metabolism. 86 (2001) 104-109.

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