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Functional Connectivity

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  • Functional Connectivity

    Posted by Gil Haight<script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,22,8,29,0), dfrm, tfrm, 0, 0, 0, 0)); </script> (Member # 691) on 22-09-2005 15:29<noscript>September 22, 2005 08:29 AM</noscript>:

    In the wake of the recent interest given to Diane’s thread on neuromodulation, I thought there might be additional interest in discussing the relevance of the plasticity associated with pain processing pathways. Just how much or in what way PT can affect any of these influences seems to be an interesting topic indeed. The following is a cursory discussion of neuromodulation and antinociception. Given what is now known, IMO it is time for PT to enter the picture.

    In the August issue of PAIN (volume 116, (3) 173-174, an editorial by Irene Tracey discusses the issue of functional connectivity and the CNS. In light of recent advances in brain imaging we are now able to appreciate co varying activity in various regions of brain during specific experimental environments. How these various regions of the CNS are associated or “functionally connected” remains speculative as cause and effect relationships are not proved by these scans. Yet, reasonable explanations using sophisticated analysis based on anatomical connections and covariant activity can be assumed.

    In her editorial Tracey refers to a study by Mayer et al (PAIN Volume 115 issue 3) which investigated the differences in data collected from patients with Irritable Bowel Syndrome (IBS), Ulcerative Colitis (UC) and normal controls during anticipated and actual aversive rectal distension. The intension of this study was to determine how the pain experienced by those with IBS, i.e. in the absence of overt peripheral inflammation, is centrally produced. Surprisingly, pain ratings for all three groups to rectal distension were essentially the same. This was not the case for anticipated pain where ratings for the IBS group were statistically higher than the two other groups. More interestingly however, was the identification of activity in specific brain regions of the IBS group as being significantly different than for the UC group or controls. In fact the scans for UC and controls were for the most part the same. Limbic and paralimbic structures, known to be facilitatory for the pain experience were active in the IBS group whereas areas of the frontal cortex (DLPFC) and brain stem (PAG) associated with pain inhibition were active in the other two groups. Tracey suggests that the Limbic/paralimbic regions facilitate pain by inhibiting the inhibitor. That is, by turning down the brain stem structures known to be antinociceptive. Additionally Tracey points out that many studies have suggested a role for the frontal cortices in either “mediating or controlling activity in key pain processing brain regions.” For instance, attention or hyper vigilance is a facilitator of pain and distraction and the placebo response are inhibitors of pain. It is becoming increasingly clear how this actually happens and it appears to ultimately involve the medullary/pontine networks and their influence on the dorsal horn of the spinal cord.
    It is widely accepted that regions of the ventral rostral medulla (PAG) as well as other medullary nuclei, have profound effects on the dorsal horn of the cord thereby influencing transmission of nociception (for reviews see Fields and Basbaum, 1999). In other words, this region can literally determine the required threshold to overcome to experience pain. To complicate matters, these effects have been shown to be bi-directional that is they have both on and off influence. For instance, output from this region to the cord is quite opposite in acute vs. chronic inflammation (for reviews see Dubner and Ke Ren, 1999). It is also widely accepted that this same region of the medulla receives sensory input from the dorsal horn and is therefore logically suited for various feedback activity. For the alligator this is the end of the story and all activity is completely unconscious. . In higher organisms however, input to the medulla is derived from both peripheral (bottom up) and central (top down) origins. The top down influence is of course extremely complex. Conscious and unconscious emotions, beliefs, attitudes, memories etc. all go into the mix. What about motor activity and its role in neuromodulation? There seems to be very little written about this. Motor tracts originating from the motor cortex, cerebellum and red nucleus all send collaterals to the medulla/pons. Also, it has also been reported that deep brain stimulation of the motor cortex produces antinociception (Tsubokawa, 1993).
    So, what do you think? Is there a basis for your techniques based on the above? I have additional thoughts specific to SC but thought this was enough to get started.
    <hr> Posted by Diane (Member # 1064) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,22,8,55,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 22-09-2005 15:55<noscript>September 22, 2005 08:55 AM</noscript>:

    Hi Gil,
    Food for thought! [IMG]smile.gif[/IMG]
    "What about motor activity and its role in neuromodulation? There seems to be very little written about this."

    So true. Couple small thoughts:

    1. That Pat Wall thought about nocioception; withdrawal, defence, resolution.
    2. The activity of all smooth muscle (the skin in the neck has oodles of smooth muscle cells) and the autonomically driven tissues - vasculature, secreting cells, etc, is all motor also.. motor isn't just striated muscle.
    3. That cluey Aus-teo-path, Luke, picked up from the workshop in Nanaimo a clue about "where" Barrett puts his hands: He observed that Barrett touches on the side of the head/body/limb/whatever that is moving away, the escaping side, not the side that is coming toward. Sort of the opposite of what I remember learning (dogma) in school about assisted active movement. I can only think that the sensory neuromodulation on the lengthening side would stimulate sensorimotor awareness of eccentric contraction. My understanding of aware eccentric movement is that it encourages awareness or reawakening of relaxation or as Barrett prefers to call it, "softening."
    <hr> Posted by Mike T. (Member # 4226) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,22,12,43,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 22-09-2005 19:43<noscript>September 22, 2005 12:43 PM</noscript>:


    Your post makes sense based on clinical observation. We probably have all had a pt. whom could not/would not move too far in a particular direction due to pain. Sometimes when you distract this person, usually just chatting with them, their ROM increases. It often isn't until the person realizes how far they have moved that they suddenly feel pain. If we are lucky, they are surprised by the movement but don't feel the pain.

    mike t
    <hr> Posted by Randy Dixon (Member # 3445) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,22,14,29,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 22-09-2005 21:29<noscript>September 22, 2005 02:29 PM</noscript>:

    About #3 of Diane's list. I found it interesting. If you have a dog, and it likes you, you can observe something relevant. If you push against them, as in trying to make them sit by pushing down, they automatically push back and resist. If you place your hand on them gently they lean into it.

    Many trainers use this.
    <hr> Posted by Gil Haight (Member # 691) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,23,7,30,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 23-09-2005 14:30<noscript>September 23, 2005 07:30 AM</noscript>:

    Diane- I agree very much with your point about smooth muscle and efferents. It is a part of the biologically appropriate response.
    Mike- True, but that is not the point I'm trying to make. Maybe the following will make it more clear.
    One of the major obstacles confronting a model suggesting Physical Therapy as a neromodulatory agent, is to account for success after the application of the therapy is complete. Typically, this problem is resolved by assuming that the origin of nociception has been eliminated by some tissue based correction. This is a huge problem with techniques such as massage, TENS or even pain meds. For Simple Contact, it has been proposed that the movement elicited is enough to restore adequate neurodynamics.I feel this is entirely reasonable and has been personally confirmed anectotely. However, my reasons for submitting all of this is to offer additional support for the efficacy of a technique which does nothing more manually than touch.

    1) Under normal circumstances movement identified by P. Wall as being biologically appropriate, facilitates an antinopciceptive response primarily through the brain stem structures. The necessary tracts are there. This holds true for all three stages outlined by Wall; withdrawal, protection and restoration.

    2) Under different circumstances the endogenous antinociceptive mechanisms are inhibited by higher centers and movement hurts. For example: Fear avoidance behavior(limbic/paralimbic), disease conviction or loss of self efficacy (frontal lobes), restricted movement through social imposition ( premotor/motor cortices) In other words, the "piggy backed" arrangement, allows for a clamping down of the lower by the higher.

    3) An interesting sidelight to all this is another antinociceptive mechanism; Sandkuler,1996, also see Randich and Maximer University of Iowa. Apparently peripheral receptors located in the heart, lungs and carotid arteries known as baroreceptors, also facilitate an antinociceptive response. Theses pathways form a bottoms up mechanism but still involve the medullary pathways described above. This accounts for why aerobic exercise works to relieve pain. Unfortunately, if ones' brainstem capacity to inhibit pain is strongly inhibited from above, attempts to improve through fitness could actually be provocative, e.g. fibromyalgia.

    4) The encouragement of instinctual movement (ideomotion) seems to be a logical approach to the dilemma. The reluctance to allow instinctual movement to occur likely involves simultaneous activation of antagonistic patterns. This then is the disruption of the normal flow between the motor cortices and the brain stem.

    5) A concern does exist however. If pain relief through the expression of idiomotor activity is achieved and the patient responds by saying "so what", they will likely continue to be in trouble. I don't mean to be glib here, but I do feel the pt. needs to be impressed and/or surprised by their response if success is to be achieved. Although this certainly does not prove the model, it would account for a fundamental role of the human part of us in the perpetuation of the common chronic pain syndromes.
    <hr> Posted by Diane (Member # 1064) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,23,8,11,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 23-09-2005 15:11<noscript>September 23, 2005 08:11 AM</noscript>:

    Gil, seems to me that you've been very busy thinking all this through. I think you should be an honorary member of the Nanaimo group.
    [IMG]smile.gif[/IMG] ,
    <hr> Posted by Gil Haight (Member # 691) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,23,8,15,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 23-09-2005 15:15<noscript>September 23, 2005 08:15 AM</noscript>:

    Thank You.
    <hr> Posted by Barrett (Member # 67) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,23,8,50,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 23-09-2005 15:50<noscript>September 23, 2005 08:50 AM</noscript>:

    Hi Guys,

    I am following along and enjoying this discussion. Gil often remains silent for prolonged periods and then suddenly posts something that indicates he must have spent that time thinking very carefully, and this is certainly true here. Diane's and Luke's observations and speculation regarding my personal way of handling intrigues me and I will post some thoughts this weekend.

    Just now I'm battling my way back home from another Cross Country tour. Hurricane Rita was bearing down on me and I thought I had made a clean getaway until the plane had to make an emergency landing in Kentucky very late last night. At the moment I'm in Chicago, I think.
    <hr> Posted by Diane (Member # 1064) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,24,12,31,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 24-09-2005 19:31<noscript>September 24, 2005 12:31 PM</noscript>:

    I'm glad you made it out in the nick of time.

    I think a glimmer of an answer to Gil's original thought will be found in the Motor Cortex thread under "VII. MOTOR FUNCTIONS OF THE SOMATOSENSORY CORTEX".
    <hr> Posted by Barrett (Member # 67) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,25,7,52,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 25-09-2005 14:52<noscript>September 25, 2005 07:52 AM</noscript>:


    Again, wonderful work on the underlying brain function. When someone asks about what might be happening aside from increased blood flow to account for the pain relief seen secondary to ideomotion, well, I'll point them your way.

    I can't help but notice how a little time spent looking into the research reports now available justifies theory, to say nothing of how much it explains about clinical work. This is almost entirely lacking in the highly touted studies of gross manipulation by our colleagues in the armed services. They seem to say, "Just do this and don't worry about the mechanism of relief-no one, especially the patient, cares about how something works." Makes you wonder why we went to college.

    Luke's observation of my handling sequence-that I tend to touch the lengthening part-is especially interesting. Of course, I didn't know I was doing this but wouldn't deny it. I still feel driven to move my contacts in an intuitive way and teach others to follow suit. Of course, I'm defining "intuition" as does Malcom Gladwell in Blink.

    My emphasis on the sensitivity of the skin makes sense here though. A lengthening part will enhance the stretch-activated ion channel activity in the epithelium and provide a better doorway/doorbell there. I hadn't thought of this before but seem to be reacting to it. Not unlike Jed Clampett's reaction to the doorbell; in response to the chime he anticipated a knocking, not quite seeing the connection fully. (See "The Ignorance of Jed on my site)

    Thanks Gil. Dinner's on me in Appleton if you can make it.
    <hr> Posted by Gil Haight (Member # 691) on <script language="JavaScript1.3" type="text/javascript"> document.write(timestamp(new Date(2005,8,27,11,9,0), dfrm, tfrm, 0, 0, 0, 0)); </script> 27-09-2005 18:09<noscript>September 27, 2005 11:09 AM</noscript>:

    I'm always happy to be used as a resource for your work, hell it is my work too. It seems the pool of interested parties is expanding and after all this time it must be rewarding.
    I'm looking forward to dinner and not just because you have offered to pay.
    Last edited by bernard; 29-12-2005, 05:51 PM.
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