Examining the influence of brain stimulation to the medial prefrontal cortex on the self-reference effect in memory.

Abstract

Past work shows that processing information in relation to the self improves memory which is known as the self‐reference effect in memory. Other work suggests that transcranial direct current stimulation (tDCS) can also improve memory. Given recent research on self‐reference context memory effects (improved memory for contextual episodic details associated with self‐referential processing), we were interested in examining the extent stimulation might increase the magnitude of the self‐reference context memory effect. In this investigation, participants studied objects superimposed on different background scenes in either a self‐reference or other‐reference condition while receiving either active or sham stimulation to the dorsal medial prefrontal cortex (dmPFC), a cortical region known to support self‐reference context memory effects. Participants then completed a memory test that assessed item memory (have you seen this object before?) and context memory (with which background scene was this object paired?). Results showed a self‐reference context memory effect driven by enhanced memory for stimuli processed in the self‐reference compared to the other‐reference condition across all participants (regardless of stimulation condition). tDCS, however, had no effect on memory. Specifically, stimulation did not increase the magnitude of the self‐reference context memory effect under active compared to sham stimulation. These results suggest that stimulation of the dmPFC at encoding may not add to the memory benefits induced by self‐referential processing suggesting a boundary condition to tDCS effects on memory.