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Abstract

Knowledge extracted across previous experiences, or schemas, benefit encoding and
retention of congruent information. However, they can also reduce specificity and augment
memory for semantically related, but false information. A demonstration of the latter is
given by the DeeseeRoedigereMcDermott (DRM) paradigm, where the studying of words
that fit a common semantic schema are found to induce false memories for words that are
congruent with the given schema, but were not studied. The medial prefrontal cortex
(mPFC) has been ascribed the function of leveraging prior knowledge to influence encoding
and retrieval, based on imaging and patient studies. Here, we used transcranial magnetic
stimulation (TMS) to transiently perturb ongoing mPFC processing immediately before
participants performed the DRM-task. We observed the predicted reduction in false recall
of critical lures after mPFC perturbation, compared to two control groups, whereas veridical
recall and recognition memory performance remained similar across groups. These
data provide initial causal evidence for a role of the mPFC in biasing the assimilation of
new memories and their consolidation as a function of prior knowledge.