The role of the prefrontal cortex in familiarity and recollection processes during verbal and non verbal recognition memory: a rTMS study

Neuroimaging and lesion studies have documented the involvement of the frontal lobes in recognition memory. However, the precise nature of prefrontal contributions to verbal and non verbal memory and to familiarity and recollection processes remains unclear. The aim of the current rTMS study was to investigate for the first time the role of the DLPFC in encoding and retrieval of non verbal and verbal memoranda and its contribution to recollection and familiarity processes. Recollection and familiarity processes were studied using the ROC and unequal variance signal detection methodologies. We found that rTMS delivered over left and right DLPFC at encoding resulted in material specific laterality effects with a disruption of recognition of verbal and non-verbal memoranda. Interestingly, rTMS over DLPFCs at encoding significantly affected both recollection and familiarity. However, at retrieval rTMS did not affect recollection and fam iliarity. Our results suggest that DLPFC has a degree of functional specialisation and plays an important role in the encoding of verbal and non verbal memoranda.