Recollection and Familiarity in Recognition Memory: An Event-Related Functional Magnetic Resonance Imaging Study

TLDR

The study addresses whether recollection and familiarity in recognition memory elicit distinct neural signatures, a question that remains unresolved. Using event‑related fMRI, 12 healthy volunteers performed study and recognition tasks, making recollection (R), familiarity (K), or no‑memory (N) judgments while brain activity was recorded. Results revealed that R and K judgments activated left prefrontal and parietal cortices relative to N, whereas temporo‑occipital and amygdala regions showed the opposite pattern; R judgments further engaged anterior left prefrontal, left parietal, and posterior cingulate areas, while K judgments recruited right prefrontal regions, indicating that distinct brain networks correspond to recollection versus familiarity.

Abstract

The question of whether recognition memory judgments with and without recollection reflect dissociable patterns of brain activity is unresolved. We used event-related, functional magnetic resonance imaging (fMRI) of 12 healthy volunteers to measure hemodynamic responses associated with both studying and recognizing words. Volunteers made one of three judgments to each word during recognition: whether they recollected seeing it during study (R judgments), whether they experienced a feeling of familiarity in the absence of recollection (K judgments), or whether they did not remember seeing it during study (N judgments). Both R and K judgments for studied words were associated with enhanced responses in left prefrontal and left parietal cortices relative to N judgments for unstudied words. The opposite pattern was observed in bilateral temporoccipital regions and amygdalae. R judgments for studied words were associated with enhanced responses in anterior left prefrontal, left parietal, and posterior cingulate regions relative to K judgments. At study, a posterior left prefrontal region exhibited an enhanced response to words subsequently given R versus K judgments, but the response of this region during recognition did not differentiate R and K judgments. K judgments for studied words were associated with enhanced responses in right lateral and medial prefrontal cortex relative to both R judgments for studied words and N judgments for unstudied words, a difference we attribute to greater monitoring demands when memory judgments are less certain. These results suggest that the responses of different brain regions do dissociate according to the phenomenology associated with memory retrieval.