Surface-based cortical morphometry in fibromyalgia reveals left temporal lobe thinning and dissociated thickness-area patterns: a FreeSurfer replication and extension study

AI Summary

Surface-based morphometry revealed significant left temporal cortical thinning: inferior temporal, fusiform, middle temporal, with entorhinal involvement; large effect sizes.
A dissociation between cortical thickness and surface area: middle temporal showed laminar thinning with preserved area, inferior temporal showed concurrent thickness and area reduction.
Bilateral cerebellar cortex and right amygdala reductions, pallidum enlargement; thalamic volumes unchanged contradicting prior SBM, highlighting methodological differences.

TL;DR (AI Generated)

Surface-based cortical thickness analysis using FreeSurfer, enabling independent measurement of cortical thickness and surface area, has been applied to FM in only a small number of studies.

A thickness-area dissociation was identified: middle temporal gyrus showed laminar thinning (thickness reduced, area preserved), whereas inferior temporal cortex showed concurrent thickness and area reduction.

Basic summary

Neuroimage Rep. 2026 Nov 6;6(4):100434. doi: 10.1016/j.ynirp.2026.100434. eCollection 2026 Dec.

ABSTRACT

BACKGROUND: Fibromyalgia (FM) is a nociplastic pain disorder associated with structural brain changes. Surface-based cortical thickness analysis using FreeSurfer, enabling independent measurement of cortical thickness and surface area, has been applied to FM in only a small number of studies.

METHODS: We applied FreeSurfer 7.4.1 to structural MRI from 20 women with FM and 20 age-matched healthy controls from OpenNeuro dataset ds001928 (GE 3T SPGR), previously analysed by Agoalikum et al. using source-based morphometry (SBM). Group comparisons of 68 Desikan-Killiany cortical parcels and 16 subcortical structures used Benjamini-Hochberg FDR correction, covarying for age (and eTIV for volumes).

RESULTS: Three cortical regions survived FDR correction (q < 0.05), all left temporal: inferior temporal cortex (d = -1.77), fusiform gyrus (d = -1.35), and middle temporal gyrus (d = -1.22); a whole-surface vertex-wise GLM independently confirmed this left temporal thinning and additionally resolved entorhinal involvement. A thickness-area dissociation was identified: middle temporal gyrus showed laminar thinning (thickness reduced, area preserved), whereas inferior temporal cortex showed concurrent thickness and area reduction. Subcortical findings included bilateral cerebellar cortex reduction (d ∼ -1.0), right amygdala reduction (d = -1.01), and bilateral pallidum enlargement (d≈+0.85); all FDR q < 0.05. Thalamic volumes did not differ between groups (p > .54), directly contradicting the main finding of the prior SBM analysis on the same subjects. Left ACC cortical thickness correlated inversely with depression severity in this FM cohort (age-adjusted GLM: partial r = -0.65, p = .003, FDR q = 0.022).

CONCLUSIONS: SBM and surface-based morphometry capture distinct structural properties in FM even when applied to identical subjects, with implications for methodological standardisation. Temporal association cortex may represent a candidate structural substrate for the cognitive symptoms of FM, though this interpretation is provisional as no cognitive measures were available in this cohort.

PMID:43032796 | PMC:PMC13762999 | DOI:10.1016/j.ynirp.2026.100434

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