S1 functional connectivity during rest and electro-acupuncture tracks median nerve and patient function improvement following acupuncture for carpal tunnel syndrome

Carpal Tunnel Syndrome (CTS) is an entrapment neuropathy of the median nerve that alters the organization of the brain's primary somatosensory cortex (S1), both structurally and functionally. Our prior research also demonstrated that electro-acupuncture (EA), both local and remote/distal to the wrist, but not sham acupuncture, improved S1 somatotopy and peripheral (median) nerve conduction. However, the mechanisms linking EA-evoked brain response during therapy with improved clinical outcomes are unknown. We investigated functional connectivity during both rest and sustained electro-acupuncture at baseline in healthy controls and CTS patients and after 8 weeks of acupuncture therapy (local, distal, or sham EA) in CTS patients. Six minutes of 3T BOLD fMRI data were collected at rest and during EA. Data were processed with FMRIPREP and FSL to generate maps of connectivity between the S1 hand region and the rest of the brain (z > 2.3, pFWE