Multimodal imaging reveals the spatiotemporal dynamics of recollection

Abstract

Functional MRI research suggests that different frontal and parietal cortical regions support strategic processes that are engaged at different stages of recollection, from pre-retrieval processing of a cue to post-retrieval maintenance and evaluation of recollected information. Whereas some of these regions respond in a domain-general way, other regions are sensitive to the type of information being recollected. However, the low temporal resolution of fMRI cannot distinguish component processes at the time-scale at which recollection occurs. We therefore combined fMRI with the excellent temporal resolution of source localised EEG/MEG to investigate the spatiotemporal neural dynamics of recollection. fMRI and EEG/MEG data were collected from the same participants in two sessions while they retrieved different types of episodic information. This multimodal imaging approach revealed striking consistency between the regions identified with fMRI and EEG/MEG, providing novel evidence of how these brain areas interact over time to support source recollection. For domain-general recollection, results from both modalities converged in showing the strongest activations in medial parietal cortex, which according to EEG/MEG was reliable at a late retrieval stage. Domain-specific source recollection increased fMRI and EEG/MEG activation in the left lateral prefrontal cortex, which EEG/MEG indicated also to be recruited during a post-recollection stage. The findings suggest that although medial parietal and left lateral prefrontal regions mediate functionally different retrieval processes, they are both engaged at a late stage of episodic retrieval.

Aging, working memory capacity and the proactive control of recollection: An event-related potential study

“…The LPN most typically onsets after the LP effect but before the participant responds. Although this onset is generally rather later than the effect we observe here, we note that several prior studies have reported onsets around 600 ms (e.g., [71,74,75]), including our own [76]. However, in their recent review, Mecklinger and others [73] suggested that negative-going old/new effects in aging studies may not be true LPN effects, arguing from the tendency of these effects to be more centrally rather than posteriorly distributed over the scalp.…”

Alpha rhythms reveal when, where and how memories are retrieved

“…Projecting our sensor data into source space, we found a striking overlap of our alpha power memory effects with the core recollection network (Figure 3). The pair-wise comparisons showed that both IR and AR effects map onto bilateral (superior/inferior parietal lobule) and medial parietal cortex (precuneus/retrosplenial cortex; see also Bergström, Henson, Taylor, & Simons, 2013). Conversely, hippocampus and medial prefrontal cortex showed specific engagement for AR (Figure 3C).…”

Memory Retrieval in Mice and Men

“…However, it is noteworthy that this far from covers the research into the phenomenology, and ultimately candidate brain mechanisms, of human memory retrieval. An additional distinction is drawn between the content of retrieval and the entering of a state that enables retrieval ("retrieval mode" [Tulving 1983], see Rugg and Wilding 2000, for a more fine-grained fractionation), or more generally between different types of item-specific and item-invariant processes in retrieval (e.g., Nyberg et al 1995;Buckner et al 1998;Köhler et al 1998;Dobbins and Wagner 2005;Duarte et al 2011;Bergström et al 2013). Further, different types of memories have been shown to involve different retrieval processes, for example, when comparing autobiographical and laboratory-based memories (Cabeza et al 2004;Svoboda et al 2006;McDermott et al 2009), field versus observer perspective (Eich et al 2009), objective versus subjective measures of recollection (see Spaniol et al 2009 for a meta-analysis) and emotional versus neutral memories (Maratos and Rugg 2001;LaBar and Cabeza 2006;Buchanan 2007).…”