Tuesday, January 22, 2008
Readers frequently ask about the definition of neuromatrix in relation to the brain and pain. Wikipedia and Google are not that helpful (yet), though there are some good links on Google to Ronald Melzack’s pioneering work. (Melzack, 1999, 2001).
Cognitive Psychology is merging to some degree with neurobiology. While the term neuromatrix has emerged with the increasing knowledge of brain neuroscience, some of the older cognitive psychology writings provide good definitions and understanding of what we now call the neuromatrix.
I like “a map of event space in the system’s coding space” (Dudai, 1989). So the coding space is all the possible combinations of connections in the brain. Pain or jealousy could be an event which would take up part of this space. The event space has been referred to by Melzack as the neurosignature. So a pain neurosignature exists within the neuromatrix. Moseley and I (Butler & Moseley, 2003), trying to be a bit trendy, refer to the neurosignature as a neurotag.
Of course it is all far more complex than this. A pain neurotag exists in a snapshot of time. It will change over time and context. Everyone’s pain neurotags are different and even our own pain neurotags will be structurally different within the brain over time.
The term “representation” is also used in relation to neurosignature.
– David Butler
Butler, D. S., & Moseley, L. S. (2003). Explain pain. Adelaide: NOI Publications.
Dudai, Y. (1989). The neurobiology of memory. Concepts, findings, trends. Oxford: Oxford University Press.
Melzack, R. (1999). From the gate to the neuromatrix. Pain, Suppl 6, S121-S126.
Melzack, R. (2001). Pain and the neuromatrix in the brain. Journal of Dental Education, 65, 1378-1382.
Searching google for “neuromatrix” now returns 41,500 results with Melzack’s 2001 paper referenced above as the top hit. It’s a seminal paper and freely available.
The neuromatrix model itself has been updated a little (notably more recent depictions has the phrase “trigger points” removed) and somewhere along the way it morphed into the “pain matrix” (Iannetti and Mouraux 2010) which then got reloaded (Legrain et al 2011 – I see what you did there), but 13 years on it still seems to be a useful conceptual model.
Perhaps the most powerful aspect of the neuromatrix model is that Melzack placed pain on the right hand side – as an OUTPUT (along with other protective responses including immune, endocrine and motor) of the Body-Self in response to numerous and contextual inputs – not just nociception.
Where to from here? Is the neuromatrix model too neurocentric? Do we need a biomatrix model? What might we be flashing back to in another 6 years?
Iannetti GD and Mouraux (2010). From the neuromatrix to the pain matrix (and back). Experimental Brain Research, 205(1) 1-12.
Legrain V, Iannetti GD, Plaghki L and Mourax A (2011). The pain matrix reloaded: a salience detection system for the body. Progress in Neurobiology, 93(1) 111-124.
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