This blog starts with a familiar story. One I have personally experienced, and one I expect other parents have too. You are shopping in a large grocery store with your young child, a long list of items to get, and need to get in and out quickly. After comparing prices on pasta sauce you lean over to say something to your daughter, but she is gone!?! “She was just there”, you think (as you mumble some unheard words under your breath). A very mild panic begins. You look down the next aisle, not there. The panic slowly increases. The longer she is missing the more your mind races to all the negative outcomes possible as your heart rate and walking speed increase. You feel a combination of nervousness, fear, anxiousness, and anger that she did not listen to your 8th request to stay by your side. Though, most of all, you feel a deep concern for her safety. Then it happens, you find her! Safe and sound, six aisles over in the candy section, without a care in the world, like nothing happened, happy to see you because she wants to buy some gum.You hug her, she gets in trouble, and of course she does not get the gum. The lost is found. All the emotions quickly settle as you finish shopping.
For some it was not a lost child. It may have been a missing pet, wedding ring, or money. Whatever valuable item was lost the inevitable race to find it began. A mix of emotions followed until the lost item was found. The more valuable the item, the more emotion and reaction felt.The response to losing something valuable is a seemingly universal human trait we all share.
Can you remember a time you lost something valuable and how you felt?
How we respond to something being lost is analogous to how our brain may respond when it loses sight and awareness of a painful body part.To many in the world of pain science this is not a new concept. A highly skilled PT I recently spoke with said he has been considering blurry, fuzzy, and smudged cortical brain maps in his assessment and treatment for at least 10 years. I am willing to bet though, a lot of PT’s have yet to discover the untapped potential for considering cortical brain maps as part of a multimodal approach for treating pain.
You likely remember learning of cortical brain maps in neuroanatomy, but you may not have learned that these brain maps can become altered in some cases of pain. Neuroscience has told us for years, starting in the 1930’s with Dr. Wilder Pinfield, that our physical body is neurologically represented within the brain in the form of neuroplastic cortical maps. These brain maps, named primary somatosensory cortex (S1- homunculus) and primary motor cortex (M1), provide us with conscious body perception, awareness, and appreciation of self.1
Adriaan Louw often says:
“Brain maps are genetically coded, environmentally sculpted, and change within minutes according to any sensory input they receive”
Maps are normally very sharp and clear when they receive regular somatic and peripheral input. These inputs give the brain an ability to see each body part clearly, to optimize the function of brain outputs. Maps are extremely neuroplastic and are highly responsive to any sensory input received. What you feed a map, informs a map. Lots of practice playing soccer makes you game ready, while little or no practice alters your timing making you ineffective and less competitive. I could go on with old adages like practice makes perfect, use it or lose it, etc, but this is the heart of cortical brain maps. When it comes to brain maps the more you use it, the sharper it is.
Focused research of cortical maps surfaced while studying complex regional pain syndrome and phantom limb pain. However recent research shows that cortical reorganization may be present with many chronic conditions, especially chronic lower back pain.2
My current understanding of smudging says that in times of persistent pain, or intense acute pain, the part or parts of our map involved with the pain may shift in how it excites, inhibits, and interprets sensory information locally at the map and at surrounding neurons. This shift can be viewed as a reorganization of brain circuitry (unhealthy neuroplasticity). A normally crisp and clear, genetically coded map may begin inviting neighboring neurons to join in its response to threat as a means to protect. While the invited neighbor neurons excite to join brain map neurons; the inviting cortical map neurons disinhibit allowing new synaptic relationships to develop between the two neuron groups.The invited neighboring neurons now pollute the once sharp and clean maps. This map pollution is called brain map smudging. The genetically programmed map has been changed with unhealthy plasticity accompanied by potentially negative sculpting from the environment. This affects map output! In some cases once maps are smudged, they may stay smudged until treated. Considering the initial story in the blog, think of smudged as being lost.
S1- homunculus map smudging seems to be a potential biological and physiological change that can occur with any injury or bout of pain. Many view this as one of many potential ways a brain may attempt to protect itself from perceived threat. The evidence suggests that smudging can occur for many reasons, such as the one outlined above, but there are many thoughts and ideas about how and why smudging happens without a definitive causation. It is indeed a complex neuroplastic phenomenon that will require more study to fully understand.3
So we pause here, to consider the emotions and feelings experienced when we lose something valuable. We also consider that the brain itself may react in a similar way when it loses a part of its cortical map to smudging. Once a part of the map has been smudged, or lost, our brain may react with the same nervous, fearful, anxious, angry, and concerned emotions. The influence of these emotions likely drive output actions and behaviors that promote and sustain protective strategies until the lost is found.
Next time, I will explore some clinical presentations to consider when trying to decide if the patient you are treating is secretly asking “Oh Body Part Where Art thou?”
What are your thoughts and responses? I would love to hear them.
- Wand BM, et al., Cortical changes in chronic low back pain: Current state of the art and implications for clinical practice, Manual Therapy (2010), doi:10.1016/j.math.2010.06.008
- Moseley GL. I can’t find it! Distorted body image and tactile dysfunction in patients with chronic back pain. Pain 2008;140:239 -243
- Apkarian AV, Baliki MN, Geha PY. Towards a theory of chronic pain. Progress in Neurobiology 2009; 87(2):81e97.