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.

Keywords: Episodic retrieval; Subsequent memory, foils, left inferior frontal gyrus; fMRI.

Fig. 1

fMRI results for ROI analysis of successful retrieval of semantic (A) and non-semantic (B) information.

Fig. 2

Inflated brain activations of subsequent memory effects.

Fig. 3

Parameter estimates extracted from the LIFG subsequent memory ROI for both semantic and non-semantic foils that are subsequently remembered and forgotten in phase 3, illustrating the significant subsequent memory by foil condition interaction.

Fig. 4

Inflated brain activations of conjunction analysis for phase 1 and phase 2 activity in the LIFG for semantic (A) and non-semantic (B) processing and foil encoding.