An ERP Study of the Dissociation between Recollection- and Familiarity-Related Prestimulus Encoding Activities

Recent findings in long-term memory suggest that successful encoding is modulated by the neural activities prior to encountering the to-be-encoded items. The current study examined whether this “prestimulus subsequent memory effect” dissociates between recollection- and familiarity-related encoding. Participants first engaged in a study phase, during which they made one of two types of judgments to concrete nouns. The judgment to be made for each word was signaled by a cue presented prior to the nouns. In the following test phase, participants differentiated studied words from unstudied ones. They were also asked to identify the type of judgment made to the identified words at study. ERPs elicited by the task cues during the study phase were sorted according to whether the following study items were recognized and their sources (i.e., judgment type during encoding) correctly identified in the subsequent recognition test. The cue-eliciting ERPs were found to be more negative-going over the left frontal area when the study items were correctly identified (hit trials) in comparison to those that were incorrectly rejected (miss trials). Importantly, when the hit trials were further segregated according to their source judgment accuracy, source-correct hit trials gave rise to a frontally distributed negativity in comparison to source-incorrect ones. Source-incorrect hit trials, on the other hand, were associated with a widespread positivity when compared with miss trials. On the basis that source correct hits involve both recollection- and familiarity-based recognition whereas source incorrect hits involve familiarity only, we argue that the current findings reflect dissociable prestimulus subsequent memory effects for subsequent recollection- and familiarity-related encoding activities.