Reversal of brain connectivity and intrinsic brain activity in Fibromyalgia patients through neuromodulation with tACS

• Grant number: 22/12916-9
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2023
• End date: May 31, 2025
• Field of knowledge: Humanities - Psychology - Cognitive Psychology
• Principal Investigator: Pedro Jose Montoya Jimenez
• Grantee: Pedro Jose Montoya Jimenez
• Host Institution: Centro de Matemática, Computação e Cognição (CMCC). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Associated researchers: Abrahão Fontes Baptista ; Ana Lúcia Yaeko da Silva Santos ; Ana María González Roldán ; Deise Ferreira da Silva ; Felipe Aydar Sandoval ; José Garcia Vivas Miranda ; Stefan Duschek ; Tiago da Silva Lopes ; Yossi Zana

Abstract

Patients with chronic pain are characterized by plastic changes in brain activity related to theperception of pain, but also in response to the cognitive and affective processing of non-painfulbodily information, including the facial expressions of pain in others. Most current evidence points to a central sensitization mechanism caused by the maintenance of pain over time. Along with pharmacological interventions, physical, behavioral, and cognitive interventions have been shown to produce short-term pain-relieving effects. In recent years, neuromodulation techniques (such as transcranial electrical and magnetic stimulation) have been shown to produce clear effects on cognition and emotions, as well as pain perceived by both healthy people and chronic pain patients. In particular, transcranial alternating current stimulation (tACS) has proven to modulate ongoing brain activity, forcing the membrane potential ofneurons in the cortex to oscillate from their resting state. Furthermore, it is hypothesized that alpha tACS (10 Hz) may have inhibitory effects on the somatosensory cortex and thereforereduce the hyperexcitability associated with chronic pain. However, little is known about theneurophysiological mechanisms underlying these effects and whether alpha tACS can reversechanges in connectivity and intrinsic brain activity in patients with fibromyalgia. Here, weexamine the effects of alpha tACS on resting EEG oscillations, functional connectivity, andevoked potentials elicited by emotional faces depicting facial expressions of anger, happiness,and pain, as well as neutral faces in fibromyalgia patients. We expect that tACS will produce:1) a significant modulation of alpha (increases in the power density, frequency peak, coherence) and theta (decrease in the power density) frequencies; 2) a "normalization" of the functional connectivity of the frontal and somatosensory regions; and 3) a significant increase in theamplitudes of late components and a reduction in the early components of visual evoked potentials in response to affective facial expressions. The findings of the present project will help to understand whether neuromodulatory techniques such as tACS can reverse the plastic changes triggered by the maintenance of pain over time. (AU)