Recollection- and familiarity-based memory in healthy aging and amnestic mild cognitive impairment

Little is known about the cognitive mechanisms of the memory impairment associated with amnestic mild cognitive impairment (aMCI). We explored recollection and familiarity in 27 healthy young adults, 45 healthy older adults, and 17 individuals with aMCI. Relative to the younger adults, recollection was reduced in the older adults, especially among those with aMCI. Familiarity did not differ among groups. In the healthy younger and older adults, better performance on a set of clinical memory measures that are sensitive to medial temporal lobe functioning was associated with greater recollection. In addition, among the healthy older adults better executive functioning was also associated with greater recollection. These results are consistent with the notion that recollection is a product of strategic processes mediated by the prefrontal cortex that suppport the retrieval of context-dependent memories from the hippocampus. Hippocampal atrophy associated with aMCI may disrupt this brain network, and thereby interfere with recollection.