DLPFC in emotional memory retrieval. rTMS effect on familiarity and salience

Introduction There is a general agreement about the role of the DorsoLateral Profrontal Cortex (DLPFC) in memory processes. However, the debate on how and when the DLPFC may be specifically involved is still open: some studies suggested its involvement in the encoding phase while others reported it in the retrieval phase (Turrizzani et al., 2010). Moreover, recent fMRI studies found that the retrieval of emotional material activates DLPFC. In addition, DLPFC seems to be crucial in familiarity effect. The aim of the present study is to investigate the role of DLPFC during the retrieval phase by using verbal material with emotional traumatic (more salient) and emotional non traumatic content (less salient) in subjects with different levels of familiarity to the stimuli. Methods Twenty five participants were asked to performance a retrieval task composed by verbal material with and without traumatic emotional content. Ripetitive Transcranial Magnetic Stimulation (rTMS) was provided during the retrieval phase over the left DLPFC. Results We found an interaction effect between the stimulation site and the traumatic content of the retrieved material as function of the familiarity effect. Conclusions Our study provided evidences in favour to the hypothesis that DLPFC is involved in the retrieval phase, and that this frontal network may be involved in the processing of salient material.