Retrieval of associative information congruent with prior knowledge is related to increased medial prefrontal activity and connectivity

Abstract

We remember information that is congruent instead of incongruent with prior knowledge better, but the underlying neural mechanisms related to this enhancement are still relatively unknown. Recently, this memory enhancement due to a prior schema has been suggested to be based on rapid neocortical assimilation of new information, related to optimized encoding and consolidation processes. The medial prefrontal cortex (mPFC) is thought to be important in mediating this process, but its role in retrieval of schema-consistent information is still unclear. In this study, we regarded multisensory congruency with prior knowledge as a schema and used this factor to probe retrieval of consolidated memories either consistent or inconsistent with prior knowledge. We conducted a visuotactile learning paradigm in which participants studied visual motifs randomly associated with word-fabric combinations that were either congruent or incongruent with common knowledge. The next day, participants were scanned using functional magnetic resonance imaging while their memory was tested. Congruent associations were remembered better than incongruent ones. This behavioral finding was parallelized by stronger retrieval-related activity in and connectivity between medial prefrontal and left somatosensory cortex. Moreover, we found a positive across-subject correlation between the connectivity enhancement and the behavioral congruency effect. These results show that successful retrieval of congruent compared to incongruent visuotactile associations is related to enhanced processing in an mPFC-somatosensory network, and support the hypothesis that new information that fits a preexisting schema is more rapidly assimilated in neocortical networks, a process that may be mediated, at least in part, by the mPFC.

Figure 1.

Experimental design. On day 1, participants learned associations of visual motifs and congruent or incongruent object–fabric combinations, where the object was presented together with the motif as a written word on the computer screen, and the fabric simultaneously as a tactile stimulus underneath the computer screen. On day 2, participants were tested in the MR scanner by means of a visual item recognition test (motifs) and subsequently with an associative memory test outside the MR scanner in which the motifs served as cues and the associated word was asked for in a three-choice test.

Figure 2.

Main effect of associative memory. GLM analyses revealed a set of brain regions comprised of dorsal and ventral visual areas, inferior parietal sulci, dorsolateral and ventrolateral prefrontal cortices (cluster-level corrected; p < 0.05), and bilateral hippocampi (p < 0.05 SVC corrected; peaks [−32, −10, −12] and [22, −22, −10]).

Figure 3.

Congruency × associative subsequent memory interaction and PPI results from mPFC. The congruency × associative subsequent memory interaction showed activity (red/yellow) in mPFC (p < 0.01 cluster-level corrected), and in the left somatosensory cortex (p < 0.05 cluster-level corrected) (overlaid on the localizer scan in white/gray). A psychophysiological analysis with mPFC as seed region showed a significant coactivation (blue arrow) with the left somatosensory cortex, which was stronger for congruent hits than for incongruent hits (blue). Finally, a correlation between mPFC–somatosensory coupling and behavioral congruency benefit was found. The more connectivity present during item recognition of associatively remembered items, the higher the congruency benefit for subsequent associative retrieval (r₍₂₂₎ = 0.531; p < 0.01).