Goal-directed mechanisms that constrain retrieval predict subsequent memory for new “foil” information

Abstract

To remember a previous event, it is often helpful to use goal-directed control processes to constrain what comes to mind during retrieval. Behavioral studies have demonstrated that incidental learning of new “foil” words in a recognition test is superior if the participant is trying to remember studied items that were semantically encoded compared to items that were non-semantically encoded. Here, we applied subsequent memory analysis to fMRI data to understand the neural mechanisms underlying the “foil effect”. Participants encoded information during deep semantic and shallow non-semantic tasks and were tested in a subsequent blocked memory task to examine how orienting retrieval towards different types of information influences the incidental encoding of new words presented as foils during the memory test phase. To assess memory for foils, participants performed a further surprise old/new recognition test involving foil words that were encountered during the previous memory test blocks as well as completely new words. Subsequent memory effects, distinguishing successful versus unsuccessful incidental encoding of foils, were observed in regions that included the left inferior frontal gyrus and posterior parietal cortex. The left inferior frontal gyrus exhibited disproportionately larger subsequent memory effects for semantic than non-semantic foils, and significant overlap in activity during semantic, but not non-semantic, initial encoding and foil encoding. The results suggest that orienting retrieval towards different types of foils involves re-implementing the neurocognitive processes that were involved during initial encoding.

Alpha oscillations during incidental encoding predict subsequent memory for new “foil” information

“…The LIFG has previously been associated with semantic processing and semantic encoding strategies across many studies (Fletcher et al, 2003;Kim, 2011;Poldrack et al, 1999;Wagner et al, 1998). Together with the behavioral result that semantic foils were recognized more accurately than non-semantic foils on the final surprise foil recognition test, these neuroimaging data support the hypothesis that directing retrieval towards new semantic versus non-semantic information leads to the recruitment of distinct neural mechanisms that are predictive of subsequent memory (Vogelsang et al, 2016).…”

“…http://dx.doi.org/10.1101/141648 doi: bioRxiv preprint first posted online rather than of efficient encoding strategies in general. Furthermore, alpha decreases have been observed over left frontal electrodes in tasks requiring high semantic processing demands (Hanslmayr & Staudigl, 2014;Klimesch, 1999;Wang et al, 2012;), but have also been associated with subsequent memory effects , consistent with the idea that the left prefrontal cortex is important for successful encoding (Vogelsang et al, 2016;Wagner et al, 1998).…”

“…The results revealed that the left inferior frontal gyrus (LIFG) exhibited significantly greater subsequent memory effects for semantic compared to non-semantic foils (Vogelsang et al, 2016). A conjunction analysis revealed significant overlap in activity between semantic processing in the initial study phase and semantic foil encoding during the first memory retrieval test in the LIFG; however, this overlap in activation was not observed for the nonsemantic condition.…”

“…We first examined alpha power associated with semantic versus non-semantic processing during the initial study phase. We then investigated whether alpha power differences were again observed during successful encoding of semantic versus non-semantic foils in the first memory test, which would support the hypothesis that the incidental encoding of foils in a memory test involves the reimplementation of the neurocognitive processes that were involved during initial encoding (Bergström et al, 2015;Jacoby et al, 2005a;Jacoby et al 2005b;Vogelsang et al, 2016).…”

“…Alternatively, strategic control processes can also be recruited later on in the trial when retrieval attempts have failed or have produced ambiguous information and additional monitoring or verification is required (a form of "backend control", Halamish et al, 2012; or "late correction strategy", Jacoby et al 1999). Previous fMRI research was unable to distinguish these accounts (Vogelsang et al, 2016) because the low temporal resolution of the blood-oxygen-level dependent (BOLD) precludes investigation of at which stage of retrieval (early versus late) LIFG activity is reinstated for semantic compared to non-semantic foils. Therefore, in the current study, we recorded electroencephalography (EEG) oscillations during performance of the "memory for foils" paradigm.…”