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

Abstract

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.

FMRI contributions to addressing autobiographical memory impairment in temporal lobe pathology

“…Specifically, activity in the lateral PFC has been observed early during retrieval [28,29,44] , supporting therefore its role in strategic search operations and initial recovery processes consistent with current models of AM [1] that emphasize the reconstructive retrieval of memories. Additionally, the more ventral (orbital) portion of the lateral PFC, part of the frontotemporal junction interconnected through the ventral branch of the uncinate fascicle, has been attributed a crucial role in ecphory (triggering) of memory retrieval [45,46] and synchronisation of emotional and factual components of the personal memories during conscious self re-experiencing [47][48][49] .…”

A Partial Least Squares Analysis of the self reference effect in Alzheimer's disease: A reply to Irish

“…PLS has been widely used in studies on autobiographical memory and related processes (Burianova and Grady, 2007;Burianova et al, 2010;Addis et al, 2012). It can be used either for extracting distributed signal changes related to varying task demands (Task PLS) or for measuring distributed patterns that impact on task performance (Behavior PLS;McIntosh & Lobaugh, 2004).…”

“…In this context, Partial Least Squares (PLS) has been developed to allow identifying functional networks differentially engaged across different task conditions (McIntosh et al, 1996). This multivariate technique has then been applied to various task-related functional data Spreng and Grady, 2010;Burianova et al, 2012;Addis et al, 2012).…”

Why am I remembering this now? Predicting the occurrence of involuntary (spontaneous) episodic memories.

“…In addition to shedding light on a common everyday memory phenomenon, uncovering such underlying mechanisms has 3 Experimental Psychology: General, 142, 426-444. DOI: 10.1037 and/or auditory stimuli during an encoding phase, followed by a retrieval phase with verbal references to the presented stimuli and with the instruction to either intentionally retrieve the matching stimuli or conduct a categorization task allowing involuntary memories to occur (also see Addis, Knapp, Roberts, & Schacter, 2011;Ramponi, Barnard, Kherif & Henson, 2011). In spite of this methodological diversity, none of the previous studies have predicted the occurrence of involuntary memories on the basis of manipulations done at encoding.…”