Losses and gains: chronic pain and altered brain morphology

Abstract

As in many fields of neuroscience, alterations in brain morphology, and specifically gray matter volume and cortical thickness, have been repeatedly linked to chronic pain disorders. Numerous studies have shown changes in cortical and subcortical brain regions suggesting a dynamic process that may be a result of chronic pain or contributing to a more generalized phenomenon in chronic pain including comorbid anxiety and depression. In this review, we provide a perspective of pain as an innate state of pain based on alterations in structure and by inference, brain function. A better neurobiological understanding of gray matter changes will contribute to our understanding of how structural changes contribute to chronic pain (disease driver) and how these changes may be reversed (disease modification or treatment).

Keywords::

• antidepressants
• boutons
• brain
• connectivity
• cortex
• dendrites
• dendritic tree
• fMRI
• opioids
• thalamus
• voxel-based morphology

Acknowledgement

The authors would like to thank R Veggeberg for the preparation of the references.

Financial & competing interests disclosure

This article supported by a grant from NINDS (K24 NS064050) and the Mayday Fund/Herlands Pain Neuroscience Fund. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Alterations of gray matter volume in cortical and subcortical regions are present in patients with chronic pain.

• • The alterations are plastic and dynamic and show reversal with clinical remission of pain.

• • The alterations seem to depend on neural activity that may increase or decrease dendritic complexity/density. Activity depending changes correlate with such changes.

• • Changes in dendritic ‘connectivity’ have a significant effect on the behavioral expression (i.e., sensory, emotional and cognitive) and impact pain sensitization and centralization of pain.

• • Further understanding of the neurobiological underpinnings will provide insight for treatment improvement.

Notes