Low-intensity focused ultrasound to the posterior insula reduces temporal summation of pain

• Published in: Brain stimulation Vol. 17; no. 4; pp. 911 - 924
• Main Authors: In, Alexander, Strohman, Andrew, Payne, Brighton, Legon, Wynn
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2024; Elsevier
• Subjects: Adult; Central sensitization; Cerebral Cortex - diagnostic imaging; Cerebral Cortex - physiology; Cerebral Cortex - physiopathology; Dorsal anterior cingulate cortex; Dosing; Female; Human; Humans; Insula; Insular Cortex - diagnostic imaging; Insular Cortex - physiology; Low-intensity focused ultrasound; Male; Pain; Pain Management - methods; Pain Measurement; Ultrasonic Therapy - methods; Young Adult; Human; Low-intensity focused ultrasound; Dosing; Pain; Dorsal anterior cingulate cortex; Central sensitization; Insula
• ISSN: 1935-861X; 1876-4754; 1876-4754
• DOI: 10.1016/j.brs.2024.07.020

The insula and dorsal anterior cingulate cortex (dACC) are core brain regions involved in pain processing and central sensitization, a shared mechanism across various chronic pain conditions. Methods to modulate these regions may serve to reduce central sensitization, though it is unclear which target may be most efficacious for different measures of central sensitization. Objective/Hypothesis: Investigate the effect of low-intensity focused ultrasound (LIFU) to the anterior insula (AI), posterior insula (PI), or dACC on conditioned pain modulation (CPM) and temporal summation of pain (TSP). N = 16 volunteers underwent TSP and CPM pain tasks pre/post a 10 min LIFU intervention to either the AI, PI, dACC or Sham stimulation. Pain ratings were collected pre/post LIFU. Only LIFU to the PI significantly attenuated pain ratings during the TSP protocol. No effects were found for the CPM task for any of the LIFU targets. LIFU pressure modulated group means but did not affect overall group differences. LIFU to the PI reduced temporal summation of pain. This may, in part, be due to dosing (pressure) of LIFU. Inhibition of the PI with LIFU may be a future potential therapy in chronic pain populations demonstrating central sensitization. The minimal effective dose of LIFU for efficacious neuromodulation will help to translate LIFU for therapeutic options. •Low-intensity focused ultrasound (LIFU) can non-invasively target subregions of the insula and anterior cingulate.•LIFU to the posterior insula reduced pain ratings during temporal summation of pain but not conditioned pain modulation.•Estimated in vivo pressure varies across participants and brain targets and may help explain LIFU’s effects.