Wednesday, June 26, 2013

Melzack&Katz, Pain. Part 10d: Conclusion 3: The brain's sense of "Self" can INclude missing parts, or EXclude actual parts, of the biological body

The paper, Pain

Previous blogposts:

Part 1 First two sentences Part 2 Pain is personal Also Pain is Personal addendum., Neurotags! Pain is Personal, Always.

Part 3a Pain is more than sensation: Backdrop Part 3b Pain is not receptor stimulation Part 3c: Pain depends on everything ever experienced by an individual

Part 4: Pain is a multidimensional experience across time

Part 5: Pain and purpose

Part 6a: Descartes and his era; Part 6b: History of pain - what’s in “Ref 4”?; Part 6c: History of pain, Ref 4, cont.. : There is no pain matrix, only a neuromatrix; Part 6d: History of Pain: Final takedown Part 6e: Pattern theories in the history of pain Part 6f: Evaluation of pain theories Part 6g: History of Pain, the cautionary tale. Part 6h: Gate Control Theory.

Part 7: Gate control theory has stood the test of time: Patrick David Wall;  Part 7bGate control: "The theory was a leap of faith but it was right!"
Part 8: Beyond the gate: Self as mayor Part 8b: 3-ring circus of self Part 8c: Getting objective about subjectivity
Part 9: Phantom pain - in the brain! Part 9b: Dawn of the Neuromatrix model Part 9cNeuromatrix: MORE than just spinal projection areas in thalamus and cortex Part 9d: More about phantom body pain in paraplegics

Part 10: "We don't need a body to feel a body." Part 10b: Conclusion1: The brain generates its own experience of being in a body Part 10c: Conclusion 2: Your brain, not your body, tells you what you're feeling

[Previously: From the 2013 Melzack and Katz paper:
Third, the body is perceived as a unity and is identified as the ‘self’, distinct from other people and the surrounding world. The experience of a unity of such diverse feelings, including the self as the point of orientation in the surrounding environment, is produced by central neural processes and cannot derive from the peripheral nervous system or spinal cord. ]
[Remember, we're still underground, trying to follow that river that sank down down down into another paper a few blogposts ago, Melzack R. Phantom limbs, the self, and the brain (The D.O. Hebb memorial lecture), the one that explains the Four Conclusions in more detail. 

That word "Self" appears. Uh-oh. That's a tough one. No one has ever been able to define "Self" to anyone else's satisfaction, same as no one has ever been able to define "consciousness" or "pain" to anyone's satisfaction.] 

How are we going to get around this
Let's find out what Melzack had to say. The next section (page 5) is titled, "The Unity of the Phantom Limb Experience."

Oneness. Seamlessness. Indivisibility. 
"One of the most striking features of the phantom limb or any other body part (including the body in many quadriplegics) is that it is perceived as an integral part of the body. Even when a foot is dangling "in mid-air" (without a connecting leg) a few inches below the stump, it is still felt to be part of the body and moves appropriately with the other limbs and torso. When a prosthesis is put on, the dangling phantom foot usually lowers into the show and the whole artificial leg is felt as a part ofd the body. The reality of these experiences derives in large part from the feeling of unity of the phantom part and the real body." 
My bold. 
"An integral part of the feeling of unity of the phantom limb (or other body part) with the remainder of the body is the feeling that the phantom is part of one's self." 
My bold again. 
"The phantom foot, penis or breast is described not only as real but as unquestionably belonging to the person. While this may seems self-evident, there is reason to believe that particular brain processes underlie the experience of the self. Just as extraordinary as the persistent experience of a limb after it has been amputated is the converse - the denial that a part of the body belongs to one's self (Denny-Brown et al 1952, Mesulam 1981)"
The Mesulam abstract mentions a hypothetical four-part network comprised of parietal, frontal, limbic and reticular regions as important for a unified sense of extrapersonal space, based on lesion studies; damage to any of these areas results in region-specific neglect impairment. 

Back to Melzack:
"Typically, the person, after a lesion of the right parietal lobe or any of several other brain areas (such as the left parietal lobe, cingulum, thalamus and midbrain) denies that a side of the body is part of himself and even ignores the space on that side. There are several descriptions of patients who topple out of their hospital bed because they believe that a strange leg is in their bed, which they then try to throw out of bed with the consequence, of course, that the rest of the body follows the leg. Generally the leg (or arm, or whole side of body) is treated negatively - as undesirable."
Think of how distressing it would be, to be attached to something, physically, that you really did not want as part of your personal existence. Please, if this ever happens to me, just shoot me. But it looks like it can go the other way sometimes, too:
"On one occasion however, a patient thought that the leg belonged to an attractive woman and was happy to have it share his bed."
Melzack continues:
"From these cases and many others like them, it is evident that the brain processes that underlie the signal that says: this is my body, it belongs to me, is part of my self." 
My "Self" - my "I"-illusion, created for me by my brain, without which I would have no sense of seamless continuity (of me inside my physicality) or separation (from the rest of the world). All messed up about the space, inside and out. A network my brain develops that produces personal boundaries in time and space. 

Melzack again:
"We take this for granted. But the effects of these lesions indicate that there are parts of the brain which impart a special signal that provides the basis for experience of self. When these areas are lost, the person denies that a part of the body belongs to the self." 
Or if they never formed from the beginning - let's not forget xenomelia and Brugger
"These patients provide powerful evidence that the brain distinguishes between self and not-self. The self is accepted; the not-self is denied. An artist who suffered this kind of brain damage would simply not paint one side of his face in his self-portrait. As he began to improve, he added more details to the previously denied face. However, more than the self is involved. When these people draw the numbers of the hours on a clockface, they crowd all the numbers on one side. Or if they draw a daisy, they draw the petals on one side only. The self, then, includes the space that surrounds the self (Denny-Brown, Meyer & Horenstein 1952; Mesulam 1981)"
"The not-self is not merely denied; it is rejected outright. The hostility and rejection with which the not-self is regarded is indicated by the instances in which the not-self leg is thrown violently out of bed or the patient desperately asks the nurse or doctor to remove the not-self leg or arm from the bed. The negative feelings are evident."

My bolds. Yup, I'd certainly feel that way. 

[I feel that very same way about "pain" - it isn't me, doesn't belong to me, I want to kill it. My brain rejects it as not-self. 
Or maybe that's just me. Maybe that's why I knew what I wanted to do in life at a very young age, why I went and got a license to touch people, hire myself out as a painkiller, a hired hand, out there in the greater world.] 

Melzack again:
"A moment's thought about how each of us would feel if a stranger's leg or arm were placed in our bed and we were told that it belongs to us makes the denial and hostility easy to understand." 
My paraphrase: 
He's saying c'mon, put yourself in someone's shoes here for just a frickin' minute. Take off your blinkers and exercise your theory of mind on this. Use whatever you have in there that pass for mirror neurons combined with some imagination. How the heck would YOU feel? Wouldn't you feel invaded? Angry? Hostile? 

Melzack is so much more smooth:
"If a strange leg were put in my bed, no amount of coaxing would convince me that the leg is actually mine - that is, belongs to my "self."
He tantalizingly mentions motor behaviour, how revealing it is:  
"Extraordinarily, after particular brain lesions, this denial occurs even though the real limb is intact and is even used in movements such as walking, dressing, and eating. If not paralyzed, the limb is used in a natural way to put on clothes, but the arm that is doing the dressing is itself not put through the sleeve of a shirt or other garment; it is ignored as not-self."
He mentions a story told by Denny-Brown about a woman (elderly, religious, fastidious) who dressed in the right side of her body in her usual style, but left the left side exposed "heedlessly." Hmmnn. 

Conclusion 3: The experience of the body has a unitary, integrated quality which includes the quality of "self" - that the body is uniquely one's own and not that of any other individual.  


My take: 
The "I" illusion can INclude whatever bits of biological body it wants, even if they don't exist.
The "I" illusion can EXclude (disown) whatever bits of biological body it wants, even if they do exist. 


I wonder, though, if sense of self varies across different cultures. How "learned" (i.e., externally influenced) might an inherent brain-network sense of self, or "I" illusion, be? 
If in fact it's intrinsic, how much might it be overridden by circumstance of birth? 

As a female looking around at the world I see cultures where women are property of their families, seen as either assets or liabilities to a "group", like livestock, not as individuals in their own right. They are not allowed their own identities. They are known, socio-legally, only as the daughter of so-and-so or the wife of Who-ever. Could they ever be able to "self"-organize and toss off their oppressors? What do their "self" neurotags look like? Do they even have any? 

These female humans exist within entrenched historical, cultural, religious, social and legal invisibility. The culture overrides any brain network they might have intrinsically been born with. They do not have any rights over what happens to their own body, particularly from the waist down - yet they bear complete responsibility for whatever might happen to said body from the waist down, including death by stoning. They are not allowed any personal boundaries, near as I can tell. They must rigidly obey those proscribed by their culture. 

I just cannot fathom it. My brain has neuroplasticized around the freedom to be female, a legal human with an identity, paying taxes, and a self with personal boundaries, all at the same time.

Casting my own Theory-of-Mind, and comparing my own "I" illusion, to what my mirror neurons react to when they contemplate this aspect of vast swathes of humanity culturally imprisoned by mere biological in-y-ness, as opposed to out-i-ness, makes my particular "justice-for-"Self" neurotag's blood boil... The thought of individuals being denied access to develop their own inherent self-networks makes mine pretty cranky. Probably a topic, though, for some whole other blog, not this one. 

Additional thought: I wonder what phantom limb feels like in these individuals? 

Further reading:
Deric Bownds: The "I" Illusion.

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