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Papers of the Week

Papers: 28 Sep 2019 - 4 Oct 2019

Human Studies

2019 Nov 13

J Neurosci



Editor's Pick

Fine-grained mapping of cortical somatotopies in chronic Complex Regional Pain Syndrome.


Mancini F, Wang AP, Schira MM, Isherwood ZJ, McAuley JH, Iannetti GD, Sereno MI, Moseley LG, Rae CD
J Neurosci. 2019 Nov 13; 39(46):9185-9196.
PMID: 31570533.


It has long been thought that severe chronic pain conditions, such as Complex Regional Pain Syndrome (CRPS), are not only associated with, but even maintained by a reorganisation of the somatotopic representation of the affected limb in primary somatosensory cortex (S1). This notion has driven treatments that aim to restore S1 representations, such as sensory discrimination training and mirror therapy. However, this notion is based on both indirect and incomplete evidence obtained with imaging methods with low spatial resolution. Here, we used functional MRI to characterize the S1 representation of the affected and unaffected hand in humans (of either sex) with unilateral CRPS. The cortical area, location, and geometry of the S1 representation of the CRPS hand were largely comparable to those of the healthy hand and controls. We found no differential relation between affected vs. unaffected hand map measures and clinical measures (pain severity, upper limb disability, disease duration). Thus, if any map reorganization occurs, it does not appear to be directly related to pain and disease severity. These findings compel us to reconsider the cortical mechanisms underlying CRPS and the rationale for interventions that aim to "restore" somatotopic representations to treat pain.This study shows that the spatial map of the fingers in S1 is largely preserved in chronic CRPS. These findings challenge the treatment rationale for restoring somatotopic representations in CRPS patients.