Enhancing memory control in subthreshold depression: a tDCS study targeting right dorsal lateral prefrontal cortex

Evidence indicates that depression is associated with memory suppression deficits, which are linked to abnormal prefrontal engagement. Specifically, right dorsal lateral prefrontal cortex (rDLPFC) plays a crucial role in memory control. This study used anodal transcranial direct current stimulation (tDCS) to examine whether stimulating rDLPFC could enhance memory suppression performance in individuals with subthreshold depression.

A total of 50 individuals with subthreshold depression received a single session of either active or sham tDCS before completing the Think/No-Think task. In this paradigm, participants were presented with neutral and negative stimuli and instructed to either retrieve or suppress the task materials.

Results indicated a three-way interaction between group, valence, and memory instruction. Within the active tDCS group, memory accuracy was lower for both neutral and negative materials in the No-Think condition than in the baseline condition, indicating successful suppression. No such effect was found in the sham group. Further analysis showed a smaller suppression effect for negative relative to neutral materials within the active tDCS group.

The findings provide preliminary evidence that tDCS may facilitate memory suppression in individuals with subthreshold depression, suggesting potential relevance of non-invasive brain stimulation in addressing memory suppression deficits in depression.