Material-specific Neural Correlates of Recollection:Objects, Words, and Faces

摘要

It is unclear howneural correlates of episodicmemory retrievalndiffer depending on the type of material that is retrieved.Here,wenused a sourcememory task to compare electrical brain activity fornthe recollection of three types of stimulus material. At study,nhealthy adults judged how well visually presented objects, words,nand faces fitted with paired auditorily presented names of locations.nAt test, only visual stimuli were presented. The task was tondecidewhether an itemhad been presented earlier and, if so,whatnlocation had been paired with the item. Stimulus types werenintermixed across trials in Experiment 1 and presented in separatenstudy–test lists in Experiment 2. A graded pattern of memorynperformance was observed across objects, words, and faces innboth experiments. Between 300 and 500 msec, event-relatednpotentials for recollected objects and faces showed a more frontalnscalp distribution compared to words in both experiments. Laternin the recording epoch, all three stimulus materials elicited recollectionneffects over left posterior scalp sites. However, theseneffects extended more anteriorly for objects and faces whennstimulus categories were blocked. These findings demonstratenthat the neural correlates of recollection are material specific,nthe crucial difference being between pictorial and verbal material.nFaces do not appear to have a special status. The sensitivity ofnrecollection effects to the kind of experimental design suggestsnthat, in addition to type of stimulus material, higher-level controlnprocesses affect the cognitive and neural mechanisms underlyingnepisodic retrieval. ■