Fmri and Transcranial Electrical Stimulation (Tes): A Systematic Review of Parameter Space and Outcomes Publisher Pubmed



Ghobadiazbari P¹ ; Jamil A² ; Yavari F² ; Esmaeilpour Z³ ; Malmir N⁴ ; Mahdavifarkhayati R¹ ; Soleimani G⁵ ; Cha YH⁶ ; Shereen AD⁷ ; Nitsche MA^{2, 8} ; Bikson M³ ; Ekhtiari H⁹ Show Affiliations
Source: Progress in Neuro-Psychopharmacology and Biological Psychiatry Published:2021

Abstract

The combination of non-invasive brain stimulation interventions with human brain mapping methods have supported research beyond correlational associations between brain activity and behavior. Functional MRI (fMRI) partnered with transcranial electrical stimulation (tES) methods, i.e., transcranial direct current (tDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation, explore the neuromodulatory effects of tES in the targeted brain regions and their interconnected networks and provide opportunities for individualized interventions. Advances in the field of tES-fMRI can be hampered by the methodological variability between studies that confounds comparability/replicability. In order to explore variability in the tES-fMRI methodological parameter space (MPS), we conducted a systematic review of 222 tES-fMRI experiments (181 tDCS, 39 tACS and 2 tRNS) published before February 1, 2019, and suggested a framework to systematically report main elements of MPS across studies. Publications dedicated to tRNS-fMRI were not considered in this systematic review. We have organized main findings in terms of fMRI modulation by tES. tES modulates activation and connectivity beyond the stimulated areas particularly with prefrontal stimulation. There were no two studies with the same MPS to replicate findings. We discuss how to harmonize the MPS to promote replication in future studies. © 2020