Healthy aging is associated with declines in episodic memory. This reduction is thought to be due in part to age-related differences in encoding-related processes. In the current study, we performed an activation likelihood estimation meta-analysis of functional magnetic resonance imaging (fMRI) studies assessing age-related differences in the neural correlates of episodic encoding. Only studies using the subsequent memory paradigm were included. We found age-related under-recruitment of occipital and fusiform cortex, but over-recruitment in a set of regions including bilateral middle/superior frontal gyri, anterior medial frontal gyrus, precuneus and left inferior parietal lobe. We demonstrate that all of the regions consistently over-recruited by older adults during successful encoding exhibit either direct overlap, or occur in close vicinity to regions consistently involved in unsuccessful encoding in young adults. We discuss the possibility that this overall pattern of age-related differences represents an age-related shift in focus: away from perceptual details, and toward evaluative and personal thoughts and feelings during memory tasks. We discuss whether these age-related differences in brain activation benefit performance in older adults, and additional considerations.
Keywords: Aging; Encoding; Episodic memory; Spontaneous thoughts; Subsequent memory; Task-unrelated thoughts.
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