fMRI meta-analysis maps persistent reward-circuit hypoconnectivity in treatment-resistant anorexia, nominating rTMS and closed-loop DBS as next-step interventions

The New Scientist piece reports stalled recovery rates but understates the strength of converging circuit-level evidence. Three independent cohorts using resting-state and task-based fMRI now converge on reduced effective connectivity from the dorsal anterior insula to the nucleus accumbens in non-remitted patients, a pattern absent in weight-recovered individuals and in other eating disorders. This dissociation supplies a mechanistic target rather than a mere correlate.

Prior neuromodulation trials applied broad dorsolateral prefrontal rTMS; newer protocols informed by these maps deliver high-frequency stimulation to the left dorsolateral prefrontal cortex while monitoring real-time insula-striatal coupling via simultaneous EEG-fMRI. Early open-label data (n=24) report 42% achieving BMI >18.5 at six months versus 18% in matched historical controls, though sham-controlled replication is pending.

A key limitation is that existing datasets remain cross-sectional; only longitudinal imaging before and after weight restoration can establish whether the circuit abnormality is a scar or a causal driver. Multi-center RCTs that stratify by baseline connectivity and deliver circuit-guided stimulation are scheduled to report in 2026.