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The following is a summary of “Painful stimulation increases functional connectivity between supplementary motor area and thalamus in patients with small fibre neuropathy,” published in the August 2024 issue of Pain by Scheliga et al.

Neuropathic pain is caused due to small fiber neuropathy (SFN) symptoms. Magnetic resonance imaging (fMRI) studies revealed central changes in patients with SFN of various etiologies.   

Researchers conducted a retrospective study investigating brain functional connectivity during acute pain processing, specifically in idiopathic SFN.

They conducted fMRI with thermal heat pain application (left volar forearm) in 32 patients with  SFN and 31 HCs. The functional connectivity analyses with the right supplementary motor area (SMA), left insula, and left caudate nucleus (CN) as seed regions, respectively. The pathogenic gain-of-function variants in voltage-gated sodium channels (Nav) have been associated with SFN pathophysiology; connectivity analyses were carried out in a homogeneous subsample of patients with rare heterozygous missense variants.

The results indicated increased connectivity with the right thalamus in patients with SFN compared to controls for proper SMA, correlated with intraepidermal nerve fiber density, indicating a link between peripheral and central pain processing. Patients with Nav variants showed reduced connectivity between the proper SMA and the right middle frontal gyrus and the least connectivity between the left CN and the right frontal pole.

They concluded that functional connectivity in SFN was steady with chronic pain syndromes.

Source: onlinelibrary.wiley.com/doi/full/10.1002/ejp.4720