Effective non-invasive brain stimulation over dorsolateral prefrontal cortex for modulation of food craving and consumption: A systematic and meta-analytic review

In recent decades, non-invasive brain stimulation (NIBS) has gained attention as a potential tool for promoting dietary regulation by modulating activity in the dorsolateral prefrontal cortex (dlPFC). However, the findings from individual experimental studies and meta-analyses have been inconsistent. To address this, we conducted a meta-analytic and systematic review of past studies focusing on neuromodulation of the dlPFC. Our research included 13 studies using repetitive transcranial magnetic stimulation (rTMS; 16 samples, 506 participants) and 29 transcranial direct current stimulation (tDCS; 31 samples, 1004 participants). By adjusting the pre-post correlation, we detected small-to-moderate effect sizes of NIBS on food craving (rTMS: Hedge's g = −0.57; tDCS: Hedge's g = −0.26) and food consumption (rTMS: Hedge's g = −0.51; tDCS: Hedge's g = −0.17). Additionally, we observed that the efficacy of NIBS was influenced by various moderators, including stimulation parameters, research protocols, and participant characteristics. Notably, both rTMS and tDCS appeared to enhance dlPFC function in dietary regulation for people with eating disorders or obesity. Furthermore, these effects were more pronounced with multi-session stimulation compared to single-session stimulation. Finally, based on the existing literature, we discuss the role of the dlPFC in the appetitive reward processing pathway and provide suggestions for future research directions.