TDCS MODULATES THE CONNECTIVITY BETWEEN PREFRONTAL CORTEX AND INSULA DURING DRUG CUE EXPOSURE IN METHAMPHETAMINE USERS

Background and Aim : There is a growing body of evidence that transcranial direct current stimulation (tDCS) can modulate drug craving, but knowledge about the neural correlates of this effect is scarce.Methods : In a randomized double-blinded sham-controlled crossover study, fifteen abstinent male participants with methamphetamine use disorder were recruited from a residential center. Each subject underwent two stimulation sessions (real and sham) at two separate days with a one-week washout period. Functional magnetic resonance imaging (fMRI) data were acquired before and after each session with a methamphetamine cue-exposure task. Direct current for 20-minutes at 2mA intensity was applied with the anode and cathode electrodes placed over the right and left DLPFC (rDLPFC and lDLPFC), respectively. Functional connectivity via task-based fMRI was analyzed using psychophysiological interaction (PPI) of the DLPFC (area under each electrode) as a seed and cue-exposure contrast (drug-related vs. neutral condition) as a regressor in a linear mixed effect model.Results : Self-reported drug craving was significantly reduced after active compared to sham stimulation. The right DLPFC (area under anode) showed a stronger connectivity with the right anterior insular cortex (rAIC) and weaker connectivity with the dorsal anterior cingulate cortex (dACC) (active vs. sham). Additionally, the lDLPFC (area under cathode) showed a decrease in task-based connectivity with the bilateral AIC in the active vs. sham stimulation comparison. Conclusion : Our findings suggest that tDCS over the DLPFC modifies DLPFC connectivity to the insula and ACC during drug cue exposure. Modulation of the connectivity between saliency processing and executive control networks could be a potential mechanistic biomarker for the effects of DLPFC stimulation with tDCS.

کلیدواژه ها:

Transcranial direct current Stimulation ، Brain stimulation ، Functional magnetic resonance imaging ، Connectivity ، Drug craving ، Addiction ، Methamphetamine.