Motor cortex pain compensation is modifiable: allostatic load degrades its analgesic efficiency and rehabilitation restores it

The primary motor cortex plays an important role in pain control. Research conducted on patients with fibromyalgia and knee arthritis using electroencephalography and transcranial magnetic stimulation showed that the motor cortex's ability to compensate for pain is not a fixed state but depends on the allostatic load of the organism. A specific combination of brain signals (central theta asymmetry and intracortical inhibition) had a different relationship to symptoms depending on the level of allostatic load. A new index based on homeostatic principles predicted improvement after rehabilitation better than baseline symptom severity. In patients who improved after rehabilitation, this index decreased and brain signals adapted accordingly. The research demonstrates that allostatic load reduces the motor cortex's compensatory capacity, which can be restored through rehabilitation.