Routes to the past: Neural substrates of direct and generative autobiographical memory retrieval

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2012-02, Vol.59 (3), p.2908-2922
• Main Authors: Addis, Donna Rose, Knapp, Katie, Roberts, Reece P., Schacter, Daniel L.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Analysis of Variance; Autobiographical memory; Cerebrovascular Circulation - physiology; Cues; Data Interpretation, Statistical; Female; fMRI; Hemodynamics - physiology; Humans; Image Processing, Computer-Assisted; Least-Squares Analysis; Magnetic Resonance Imaging; Male; Medical imaging; Memory, Episodic; Mental Recall - physiology; Oxygen - blood; Partial least squares; Prefrontal Cortex - physiology; Psychomotor Performance - physiology; Reaction Time - physiology; Retrieval; Studies; Temporal Lobe - physiology; Young Adult
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2011.09.066

Models of autobiographical memory propose two routes to retrieval depending on cue specificity. When available cues are specific and personally-relevant, a memory can be directly accessed. However, when available cues are generic, one must engage a generative retrieval process to produce more specific cues to successfully access a relevant memory. The current study sought to characterize the neural bases of these retrieval processes. During functional magnetic resonance imaging (fMRI), participants were shown personally-relevant cues to elicit direct retrieval, or generic cues (nouns) to elicit generative retrieval. We used spatiotemporal partial least squares to characterize the spatial and temporal characteristics of the networks associated with direct and generative retrieval. Both retrieval tasks engaged regions comprising the autobiographical retrieval network, including hippocampus, and medial prefrontal and parietal cortices. However, some key neural differences emerged. Generative retrieval differentially recruited lateral prefrontal and temporal regions early on during the retrieval process, likely supporting the strategic search operations and initial recovery of generic autobiographical information. However, many regions were activated more strongly during direct versus generative retrieval, even when we time-locked the analysis to the successful recovery of events in both conditions. This result suggests that there may be fundamental differences between memories that are accessed directly and those that are recovered via the iterative search and retrieval process that characterizes generative retrieval. ► Personal and generic cues elicited direct and generative autobiographical retrieval. ► Both retrieval tasks engaged regions associated with autobiographical memory. ► Many of these regions were more active during direct versus generative retrieval. ► Generative retrieval differentially engaged lateral prefrontal and temporal cortex.