Does electrode localization in tDCS research matter? A comparison between 10–20 EEG system and MRI-guided neuronavigation

Although the 10–20 EEG system is frequently used to locate the dorsolateral prefrontal cortex (DLPFC) in tDCS research, due to intersubject brain variability, this method may have limited target accuracy and may result in suboptimal stimulation. To address this issue, we compared left DLPFC-localization via the 10–20 EEG system to MRI-guided neuronavigation in forty healthy female participants within the same age range. Compared to the 10–20 EEG system, MRI-guided neuronavigation localizes the DLPFC-targeting anode more latero-posteriorly. Furthermore, tDCS-induced electric fields (derived from one subject) suggest that these different localization methods induce different electric fields in distinct brain regions. Our findings indicate that prefrontal tDCS targeting methods result in distinct electrode localizations, each of which suggested being associated to unique underlying electric field distributions. Considering the frequent use of tDCS in research, an evaluation and direct comparison of the outcome of both targeting methods is therefore warranted.