The purpose of pain?

Muscle spasms have been part of Brooke’s life for some time now—sometimes they’re small, sometimes they make his legs jerk off the bed—and, more recently, neurologic pain. These things are apparently part of the natural landscape of spinal cord injury, but the question is, what do they mean? There’s been lots of debate around here, and clearly no uniform, canonical answer. But a colleague in the Psychology Department here has sent a passage from the book he’s about to publish, and Brooke has asked me to post it on the blog. It invites enormous optimism. Here goes:

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Excerpt from Alan Fogel (forthcoming, September, 2009). The Psychophysiology of Self-Awareness: Re-discovering the Lost Art of Body Sense. New York: W. W. Norton.


Twitching: Initial integration of the body schema

Most vertebrates during the prenatal and newborn period show spontaneous muscle contractions called myoclonic twitches (myo=muscle, clonus=contraction). Fetal twitches create electrical and chemical discharges in the not-yet-innervated peripheral muscles. These discharges help the nerves growing from the brainstem and spinal cord to find their targets in the muscle proprioceptors and motor neurons, linking brain and body. Once the neural connections are made, twitching continues to help calibrate the body schema by detecting limb weight and distance from other parts of the body (Khazipov et al., 2004; Petersson et al., 2003).
These twitches tend to occur when the fetus or newborn is in a completely relaxed state during sleep. They are often synchronized across different body regions so that an arm and a leg may twitch at the same time. Twitching appears to be generated by different regions of the spinal cord, brainstem, and brain working in synchrony. This synchrony between different parts of the nervous system and different parts of the body may be a built-in process that allows one’s body schema to develop via somatotopic experience dependent connections. Twitching can induce activation in the SS and motor cortices in the somatotopic areas where the moving body part is represented (Kohyama & Iwakada, 1991).
After the newborn period, twitches decrease in frequency because voluntary motor exploration of the world during waking states plays an increasingly important role in the body schema formation. If infants have brain stem immaturity, however, twitching will continue for several months longer, apparently allowing the infant to use the built-in spontaneous movements to catch up from any delays in voluntary movement control (Kohyama & Iwakada, 1991). Twitching, in other words, seems to be an essential mechanism to start the development of neuromotor links that introduce one body part to another and serve to integrate the body schema.
Is twitching important for older infants, children and adults? Typically, twitching after the newborn period is inhibited by centers in the brain and brainstem because it can interfere with experience dependent learning from normal, and preferred, voluntary movement. When there is brain damage, however, twitching may be one of the symptoms observed. On the other hand, if there is damage to the peripheral nervous system, electromagnetic stimulation to the peripheral nerve to induce twitching has been used as a treatment to assist the cortex to find, re-map, and thus re-integrate, the body (Turton et al., 2007).
One patient described in the literature had lost sensations of touch and muscular proprioception due to damage in the brain from a viral infection. Stimulating a twitch in the patient’s forefinger allowed him to eventually move the finger voluntarily (Cole & Paillard, 1995). Similarly, stimulating a somatotopic motor area of the brain electrically can induce an involuntary twitch in the related muscles (Lewis, J. W., 2006). In normally functioning adults, active sleep, which includes rapid eye movements and occasional twitches, is responsible for “physiological restoration” and integration across neural circuits (Blumberg & Lucas, 1996).
I have observed twitching in some of my clients during Rosen Method Bodywork sessions. These clients in particular report that they have little felt awareness of particular parts of their bodies. Chronic tension in those muscles damp sensation from the proprioceptors so that the person may not be able to feel my hand touching their upper back or their legs. These impairments in the body schema often result from prior trauma leading to the muscle tension (habitual defensive postures) and thus a suppression of self-awareness.
As their muscles begin to relax during treatment and as they report increasing awareness of those “missing” body regions, they sometimes twitch involuntarily. This does not appear to be a random discharge since, at least in my experience, it only occurs as the body is shifting to a relatively novel (for that client) state of relaxation and as awareness is increasing.
My guess is that the neural pathways normally responsible for proprioception, having been neglected from disuse, are once again sending signals out to other parts of the body to help “find” the lost connections. Reconstruction of the body schema following disorders of embodied self-awareness, then, may re-activate the same spontaneous prenatal and neonatal nervous discharges that were used to construct the body schema in the first place. Embodied interventions work best when they can activate the body’s own intrinsic neuromotor growth processes.


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In the blog posted yesterday I’d remarked that after the pain seemed to be receding “we’re back to optimism mode.” When I read this to Brooke he said he’s never in pessimism mode, always in optimism mode, even when the pain is bad. And there’s reason to be optimistic: he now can feel light touch in various parts of his body, including his calves, inner thighs, left hand (that’s been the case for a long time), and as of yesterday, his abdomen, and today, his right Achilles’ tendon. This is sensation, not (yet) function, but just the same it’s tremendously exciting, even as we try to keep optimism from spinning out of control and realize that at the moment he’s still almost completely paralyzed. Just the same, as Colin Powell once remarked, “optimism is a force multiplier,” and while the political circumstances might not provide the best analogy, we’re all well aware of the role optimism can play. Somebody asked Brooke the other day about depression, perhaps knowing Brooke’s extensive experience with it, and he said “I’m not depressed. I can’t afford to be depressed.” Optimism, we all think, is a much better medicine. (Thanks all of you for contributing to it!)
Peggy