Sunday, July 07, 2013

Melzack & Katz, Pain. Part 14: Side trip out to the periphery!

The paper, Pain

Most recent blogposts:

Part 13: Pain and Neuroplasticity Part 13b: Managing neuroplasticity

We have made it out into a new, very surprising and very wide part of the river, so wide it's hard to see the shore on either side, plus it's foggy right now... 


Melzack is considering peripheral input in this next section (still within the Beyond the Gate section): 
Denervation Hypersensitivity and Neuronal Hyperactivity

Which doesn't mean he has reverted to specificity theory. 
Not one bit.

We shall have to cut power to the motor, toss up the sail, and look out for possible rocks and sand bars in this stretch, because it's hard to see very far ahead just now. It's a very long section too, relatively speaking, so we'll just go slow, and take our time. We'll get through it, by carefully fathoming our way along. There are many references, so that should help us. 
(Plus, we know a couple things about neural crest, glia... We'll be fine.) 

First paragraph:
"Sensory disturbances associated with nerve injury have been closely linked to alterations in CNS function. Markus et al.32 have demonstrated that the development of hypersensitivity in a rat's hindpaw following sciatic nerve section occurs concurrently with the expansion of the saphenous nerve's somatotopic projection in the spinal cord. Nerve injury may also lead to the development of increased neuronal activity at various levels of the somatosensory system (see review by Coderre et al.33). In addition to spontaneous activity generated from the neuroma, peripheral neurectomy also leads to increased spontaneous activity in the dorsal root ganglion, and spinal cord. Furthermore, after dorsal rhizotomy, there are increases in spontaneous neural activity in the dorsal horn, the spinal trigeminal nucleus, and the thalamus."
32. Markus HPomeranz BKrushelnyky D. Spread of saphenous somatotopic projection map in spinal cord and hypersensitivity of the foot after chronic sciatic denervation in adult rat. Brain Res 1984296:2739. 
33. Coderre TJKatz JVaccarino ALMelzack R. Contribution of central neuroplasticity to pathological pain: review of clinical and experimental evidence. Pain 199352:259285.

First thought: these are pretty old papers.. 1984 and 1993.. a lot of water has flowed under the bridge since then... 

I'll come back after I've checked them out. 

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 Part 10dConclusion 3: The brain's sense of "Self" can INclude missing parts, or EXclude actual parts, of the biological body Part 10eThe neural network that both comprises and moves "Self" is (only)modified by sensory experience
Part 11We need a new conceptual brain model! Part 11b: Intro to a new conceptual nervous system Part 11c: Older brain models just don't cut it Part 11d: The NEW brain model!
Part 12: Action! 12b: Examining the motor system, first pass. 12cMotor output and nervous systems - where they EACH came from Part 12d... deeper and deeper into basal ganglia Part 12e: Still awfully deep in basal ganglia Part 12f: Surfacing out of basal ganglia Part 12gThe Action-Neuromatrix 

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