Framing memories: How the retrieval query format shapes the neural bases of remembering.

The way memory questions are framed influences the information that is searched, retrieved, and monitored during remembering. This fMRI study aimed at clarifying how the format of the retrieval query shapes the neural basis of source recollection. During encoding, participants made semantic (pleasantness) or perceptual (number of letters) judgments about words. Subsequently, in a source memory test, the retrieval query was manipulated such that for half of the items from each encoding task, the retrieval query emphasized the semantic source (i.e., semantic query format: "Is this word from the pleasantness task?"), whereas for the other half the retrieval query emphasized the alternate, perceptual source (i.e., perceptual query format: "Is this word from the letter task?"). The results showed that the semantic query format was associated with higher source recognition than the perceptual query format. This behavioral advantage was accompanied by increased activation in several regions associated to controlled semantic elaboration and monitoring of internally-generated features about the past event. In particular, for items semantically encoded, the semantic query, relative to the perceptual query, induced activation in medial prefrontal cortex (PFC), hippocampal, parahippocampal and middle temporal cortex. Conversely, for items perceptually encoded, the semantic query recruited the lateral PFC and occipital-fusiform areas. Interestingly, the semantic format also influenced the processing of new items, eliciting greater L lateral and medial PFC activation. In contrast, the perceptual query format (versus the semantic format) only prompted greater activation in R orbitofrontal cortex and the R inferior parietal lobe, for items encoded in a perceptual manner and for new items, respectively. The results highlight the role of the retrieval query format in source remembering, showing that the retrieval query that emphasizes the semantic source promotes the use of semantic strategies via medial and L lateral PFC activations. These frontal activations are accompanied by differential recruitment of more posterior regions, depending on the type of information that had been encoded.