The Connection of Pain Experiences: Subjective, Conscious, Biological, and Memory

merry2e's picture

If humans knew the answer to the question “When does pain begin?” I am not sure if our future would be brighter or if the information would be used in a way to impose laws that would prohibit the individual to maintain their own identity and autonomy.  The neurobiology of pain is a controversial topic as it relates to issues such as abortion, animals rights, and euthanasia, just to name a few.  I understand what I know and perceive pain to be, but I cannot say that I understand the pain experiences of the person sitting next to me.  Does this mean I lack empathy for my fellow sister or brother? I think not. As neurobiologists, physicians, psychologists, and scholars, attempt to sort out the anatomical connections of the central nervous system and its link to consciousness, understanding how it affects functioning of the pain system in humans, there are still many others, including politicians, activists, and religious believers who support abolishment of an array of laws, exploiting research findings to further their own causes.  The subject of pain is one full of bias and subjectivity and entwined with memory.  In order to understand pain, one must understand pain as both 1) subjective: that it can only be understood by the individual and how the individual perceives their pain, and 2) it is biological and through scientific research we can further understand the nature of pain. Through the combined understanding of the individual “feeling” of pain, based on opinion (mind), rather than facts or evidence, and the scientific data to show that pain is a part of the functions of the brain, it demonstrates the Brain + Mind connection. 

Anatomical Pathways Associated with Pain and the Fetus

A universal definition of pain includes, “A sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation.” [1]  Stuart Derbyshire, a senior lecturer at University of Birmingham School of Psychology describes the pain system as a type of alarm system.  Understanding the pain system in this light allows scientists to view a physically harmful (noxious) stimulus as an event that arouses nerves in the skin, like pushing an alarm.  The cable runs to the brain and the brain is responsible for registering the pain [2].  Understanding the development of the fetus is crucial in understanding the origin of pain and how it could relate to memory and consciousness.  Can babies respond to the stimulus of a noxious agent?  And if so, when does this begin?  As early as three weeks gestation, a fetus starts developing the brain, spinal cord, and heart.  At approximately seven weeks gestation, along with the formation of tissues, arm and leg buds, the brain develops even further into five areas with cranial nerves visible [3].  It is at this point the nerve endings or “alarms buttons” begin to develop and reach the lower thalamus, situated in the center of the brain.  The role of the thalamus is to control the flow of information to the cortex which includes the neocortex region [4].  It may be possible, anatomically, for the fetus to experience pain at this point due to the development of the pathways from the spine to the lower thalamus.  Further along in gestational development, approximately twelve to sixteen weeks, the fetus begins developing pathways from the upper thalamus to the cortex.  It is not until twenty-three to twenty-six weeks gestation that these pathways are complete, thus suggesting by some scientists that pain may not be felt in the fetus until much later in development [2]. 

“I” Function in Relation to Pain (Self Awareness)

The neocortex, as we discussed in class, is associated with the development of the “I” function or awareness of the SELF and conscious thought.  The “I” function allows humans to make choices, show empathy towards others, and create attachments with others through the use of language.  The “I” function also works as a way to communicate our needs to others by being aware of what they are.  If I am in pain, I can say, “I am in pain.”   The neocortex is made up grey matter which consists of unmyelinated fibers and cell bodies [5].  Through the neural pathway connections of the thalamus and cortex, we can see the anatomical relationship of pain and consciousness.  Another factor of the “I” function is that we do not need the entire nervous system to function to be “I,” as in the case of Christopher Reeves and others with paralysis [6].  

Where does Memory come into play?

Our nervous system, dependent upon a rudimentary form of memory witnessed in an action potential, reveals evidence in the dynamic method in which the brain and nervous system operate.  If we can have implicit memory, somatic memory, or unconscious memory, it would be reasonable to deduct the human brain, with the capacity of having “rudimentary memory” from the embryo stage that the same can happen with pain without the conscious awareness of pain. Does mere consciousness and acknowledgement of pain dictate whether pain exists?  During the next stage of life, infancy, a phenomenon known as infantile amnesia occurs based upon evidence of the hippocampus not maturing until two-three years of age [7]. The hippocampus region of the brain combined with the amygdala play a role in memory.  If an infant is not consciously aware of its surroundings, not consciously aware of whom or what is in its world, does this mean the infant does not feel pain?  If we follow the path from rudimentary memory, beginning in the action potentials of an embryonic cell, realizing that both memory and pain are strongly correlated to consciousness, the possibility of pain also beginning in a primitive variation seems possible. Pain, at either an “unconscious” level or “primitive variation” could explain a multitude of physical and mental illnesses.  After researching, I have determined there are many unanswered questions in the field of pain research. Extensive research in the area of pain holds promise for future generations and hope rather than despair for the many pain sufferers in the world.  Hopefully those who choose to exploit science to satisfy their own needs would step aside, allowing advancement in the field.        

Works Cited and WWW Sources  

[1] pain. (2003). In Webster's New World™ Medical Dictionary. Retrieved February 24, 2008, from http://www.credoreference.com.proxy.brynmawr.edu/entry/2438372 

[2] Derbyshire, Stuart W.G. “Can fetuses feel pain?” 2006. 24 Feb. 2008. <             http://www.bmj.com/cji/content/full/332/7546/909?eaf 

[3] MedlinePlus. 19 Oct. 2007. U.S. National Library of Medicine and the National Institutes of Health. 23 Feb. 2008. <http://www.nlm.nih.gov/medlineplus/ency/article/002398.htm 

[4] http://www.scholarpedia.org//article/Thalamus 

[5] http://en.wikipedia.org/wiki/Neocortex 

[6] Bio 202 Neurobiology and Behavior Course Notes-Professor Paul Grobstein. 

[7] Rothschild, Babette. The Body Remembers: The Psychophysiology of Trauma and TraumaTreatment.  New York: Norton, 2000.

Comments

Paul Grobstein's picture

Pain and the brain

"If an infant is not consciously aware of its surroundings, not consciously aware of whom or what is in its world, does this mean the infant does not feel pain?"

That's an interesting question. Maybe one that would help to clarify the "controversy"? What new understandings/questions follow from it? What is the relation between the "subjective" and the "biological"? What are the "unanswered questions" that need to be answered to reduce "controversy"?

The First Ache, in a recent NYTimes magazine, is a pretty good overview of some of these issues.

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