Transcranial direct-current stimulation (tDCS) is a noninvasive form of electrical brain stimulation that can modulate neural activity and improve behavioral performance on a variety of tasks. For example, it has been shown that tDCS delivered over the prefrontal cortex during learning can improve memory for the learned material. The proposed research seeks to demonstrate the ability of tDCS to enhance memory consolidation in a population of healthy older adults. Participants will engage in a week-long memory training intervention consisting of both declarative memory (DM) and working memory (WM) tasks. Previous work from our lab has already demonstrated improved WM performance after tDCS. The proposed research now seeks to compare the relative efficacy of tDCS on DM immediately and one-month after training. We hypothesize greater improvements on DM than WM due to the effects of memory consolidation. We will also use fMRI before and after the intervention while participants perform a similar DM task in order to measure the neural response to words learned during training. We hypothesize participants who receive tDCS will not only recall more words during training compared to sham tDCS, but will also show neural signatures in the scanner consistent with stronger memory consolidation.
