Hou 2026 — Large-scale brain network dysfunction in FM (resting-state fMRI)

One-paragraph summary

Resting-state fMRI study comparing 33 female FM patients with 33 age-matched healthy controls. Whole-brain functional-connectivity (FC) analysis with permutation FDR correction at p<0.005. Three concrete findings: (1) FM patients showed widespread hypoconnectivity within and between three major networks — default mode (DMN), frontoparietal (FPN), and somatosensory (SMN). (2) The most striking specific finding was thalamocortical decoupling — significantly reduced FC between thalamus (subcortical) and DMN, SMN, and FPN. (3) Distinct symptom-specific FC patterns: pain impact (FIQ) and anxiety (HAMA) correlated positively with thalamus-FPN FC; depression (HAMD) correlated negatively with DMN-DAN FC; alexithymia (TAS) correlated with FPN-VAN FC (FM-specific, not seen in HC). The authors' central claim: FM is a disintegration of FC across multiple large-scale networks, extending beyond classical central sensitization to involve thalamocortical integration and impaired affective/cognitive/sensory cross-talk.

Claims as triples

• thalamus — modulates → central_sensitization [evidence: thalamocortical decoupling; confidence: emerging]
• central_sensitization — present_in → fm_central_only [framework-level: network-level dysfunction extends what CS captures]

Methods note

n = 33 FM (all female) + 33 matched HC. Resting-state fMRI; whole-brain FC analysis; clinical correlations against FIQ, MPQ, HAMD, HAMA, TAS. Permutation-based FDR p<0.005 — appropriately stringent. Single-site, single-acquisition design. Authors: Hou & Xu (single-institution preprint, institution not specified in available metadata).

Limitations

• Preprint, not peer-reviewed. Network-FC findings are sensitive to preprocessing pipeline; replication needed.
• Female-only cohort. FM is female-predominant but not exclusive; generalization to male FM patients is open.
• Cross-sectional. Network-FC patterns might be a consequence rather than cause of FM, or both could share an upstream driver.
• Single-site, n=33 per arm — adequately powered for the gross effects reported but underpowered for subtype stratification.
• Resting-state FC abnormalities are non-specific — similar patterns appear in chronic pain broadly, depression, and other conditions. The FM-specificity of the alexithymia-FPN-VAN finding is interesting but should be replicated.

Open questions raised

• Does thalamocortical decoupling correlate with TSPO-PET signal in the same patients? (Maps the network-level finding onto the inflammatory-central subtype.)
• Is the decoupling cause or consequence of central sensitization? (Q2 generalized.)
• Do the symptom-specific FC patterns (FPN-VAN ↔ alexithymia) suggest an alexithymia-dominant FM subtype?
• Could thalamus-targeted neuromodulation (e.g., focused ultrasound thalamotomy as in the Mlonzi 2026 case report) reverse the decoupling?

Triangulation notes

• Adds a network-level layer to the project's mechanism map. The autoimmune thread (peripheral SGC activation) and the glial thread (central microglial activation) are molecular/cellular; this paper supplies the systems-level consequence.
• Bridges to the focused-ultrasound thalamotomy case report (Mlonzi 2026, score 2 in queue): if thalamocortical decoupling underlies CS, then reversing thalamic dysfunction should reverse CS — which the case report claims to demonstrate (n=1).
• Distinct from Strube 2026 (predictive_coding_failure framework) but compatible — the network-FC findings could be the neural substrate of disrupted Bayesian precision-weighting that Strube proposes.

Bridges

• No new bridges, but reinforces the case that network-level dysfunction is shared across nociplastic conditions (B4 — ME/CFS network-FC literature shows similar patterns).