neuroplasticity and immobility

[Tracy]

Hi Barrett -

I've had this thought knocking around in my head for a little while now, and am looking for your thoughts (or anyone else's thoughts, for that matter).

I'm working on trying to better understanding what is happening at the cortex when joints or certain regions of the body are immobilized. The classic example involves taping 2 fingers together for a few days, and then scanning the brain - the brain is only recognizing one finger secondary to the neuroplastic changes that occur with the immobility of the second finger. Untape the fingers, and scan again after some movement has occurred, and the brain recognizes 2 fingers again.

First, I'd like to better understand what creates this change - is it neurone death, altered connectivity?? Why do these changes in receptive fields occur. What is occuring physiologically to create this change??

Second, (this is the question I specifically had for Barrett) - considering this change that occurs in the cortex with immobility...I'm wondering if this would affect an individual's ability to tap into or utilize ideomotor movement.


Thanks for your input and thoughts!!

Tracy

[rajulvasa]

Hi Barrett -

I've had this thought knocking around in my head for a little while now, and am looking for your thoughts (or anyone else's thoughts, for that matter).I'm working on trying to better understanding what is happening at the cortex when joints or certain regions of the body are immobilized. The classic example involves taping 2 fingers together for a few days, and then scanning the brain - the brain is only recognizing one finger secondary to the neuroplastic changes that occur with the immobility of the second finger. Untape the fingers, and scan again after some movement has occurred, and the brain recognizes 2 fingers again.

First, I'd like to better understand what creates this change - is it neurone death, altered connectivity?? Why do these changes in receptive fields occur. What is occuring physiologically to create this change??
Tracy

Tracy,think a little longer and u will have an answer with reasoning that it certainly is not a neuron death. Second the CNS the most complex looking structure, functions very simply, it is a different matter that neurological science find it highly complex to understand and gauge the true simplicity behind the CNS functions.

U mentioned taping 2 fingers together for a few days, and then scanning the brain - the brain is only recognizing one finger secondary to the neuroplastic changes that occur with the immobility of the second finger.

brain is recognising one finger? or simply recognises one movement done by two fingers taped as one? can those who published this work on brain mapping of these finger tell which is the first finger and which is the second in terms of two taped together and second one made immobile?

[/QUOTE] what is occuring physiologically? [/QUOTE]
i can only speculate that CNS is recognising what is going on, it recognises afferent input coming from two seperate fingers moving or two coupled as one and moving as one unit.

[Barrett Dorko]

Tracy,

Thanks for asking.

I don't devote much time thinking about how or why ideomotion diminishes beyond what I say about cultural influences, and I've said a great deal about that. You seem to be implying that pain arises from its absence but I would disagree. The absence of any sort of movement isn't painful, but rather it is the mechanical deformation beyond our tolerance that forms the pain's origin - and tolerance is largely a function of the ANS.

Ideomotion being an instinct inherent to and essential for life, I think it unlikely that a little alteration in the brain is going to be sufficient to stop its emergence to some degree.

I am reminded of the passage from Sack's book A Leg to Stand On that is quoted in the thread Oliver, Ian and Me (http://www.somasimple.com/forums/showthread.php?t=2046). His leg casted for days in much the same way the fingers taped together would be, Sacks finds eventually that "new" sorts of movement suddenly begin to emerge:

“The term “ideomotor” came spontaneously to mind. The flashes I had had previously were merely motor, fragmentary spasms and twitches of an irritable nerve-muscle – there being no correspondence with any inner impulse, idea or intention. They had nothing to do with me – whereas these flashes by contrast, involuntary, spontaneous, unbidden as they were, did most certainly, and essentially, and fundamentally involve me: they weren’t just “a muscle jumping” but “me remembering,” and they united my mind and my body; they exemplified, in a flash, their quintessential unity – the unity that had been lost since my disconnecting injury.”

What is different for Sacks of course is that he obviously knows about ideomotor activity and its purpose. Without that knowledge he not only wouldn't have used it as he eventually does, he would have willfully inhibited its expression. This behavior would have probably been reinforced by an equally ignorant therapist.

[anoopbal]

IF the brain senses the immoilization, is there any evidence of brain commanding the physiological changes, like muscle atrophy in immobilization? Or how is the musle sensing immoblization?

thanks
anoop

[rajulvasa]

IF the brain senses the immoilization, is there any evidence of brain commanding the physiological changes, like muscle atrophy in immobilization? Or how is the musle sensing immoblization?

thanks
anoop

Brain commanding the physiological changes!!! like muscle atrophy in immobilization?

My assumption is brain does not waste its energy in commanding the muscle to atrophy, it commands always to contract or not contract.it is simply that muscle in no longer sending usual impulses that is the lengthening and shortening because it is immobilized, actin myosin filaments becomes inactive in its primarily mechanical job, spindle afferents primary and secondary have no business any longer as the muscle mechanics is idle and it may be leading to morphological changes?? vicious circle, brain does not receive any feed back.