Memory orientation and success: separable neurocognitive components underlying episodic recognition

Abstract

Episodic recognition can be based on recollection of contextual details, on a sense of recent encounter, or some combination of the two. According to several cognitive models, selectively attending to these distinct aspects of memory may require different retrieval orientations and result in different neural responses depending upon whether or not retrieval is successful. Using event-related fMRI, we examined retrieval orientation by having subjects discriminate between two test words in one of two manners. During source recollection, they selected the member of the pair previously associated with a particular encoding task. In contrast, recency judgment required selection of the most recently encountered item of the pair, regardless of how it had been encoded. Furthermore, successful and unsuccessful trials within each retrieval task were contrasted to determine whether retrieval success effects occurred in overlapping or dissimilar neural populations compared to those associated with each retrieval orientation. The results revealed distinct lateral prefrontal and parietal activations that distinguished attempted source recollection from judgments of relative recency; these orientation effects were largely independent of retrieval success. In contrast, medial temporal lobe structures (hippocampus and parahippocampal gyrus) were differentially more active during successful recollection of encoding context, showing similar reduced responses during failed source recollection and judgments of recency. These results indicate that different memory orientations recruit distinct prefrontal and parietal networks and that the recovery of episodic context is associated with the hippocampus and surrounding medial temporal cortices.

Prefrontal contributions to domain-general executive control processes during temporal context retrieval

“…Previous fMRI studies of recency memory have also reported greater activity in right BA 6/8 during recency memory tasks (Dobbins, Rice, Wagner, & Schacter, 2003;Dudukovic & Wagner, 2007). Moreover, Dudukovic and Wagner (2007) found that greater right BA 6/8 activity during correct recency decisions, versus correct novelty decisions; indicating that activity in this region is related to processes important for making correct recency judgments.…”

“…Neuroimaging studies have highlighted the role of various PFC regions during temporal context retrieval (Cabeza, Anderson, Houle, Mangels, & Nyberg, 2000;Dobbins, Rice, Wagner, & Schacter, 2003;Dudukovic & Wagner, 2007;Konishi et al, 2002;Suzuki et al, 2002). However, it remains unclear which of these PFC activations are related to mediating domain or task-specific cognitive control processes such as, recollection-based retrieval monitoring, familiarity-based retrieval monitoring, retrieval success and establishing retrieval mode (Dobbins, Rice, Wagner, & Schacter, 2003;Nyberg et al, 1995;Yonelinas, Otten, Shaw, & Rugg, 2005) and which are related to mediating domaingeneral cognitive control processes including strategic ordering and controlled selection processes, to name a few (Moscovitch, 2002;Rajah & McIntosh, 2006;Rowe, Toni, Josephs, Frackowiak, & Passingham, 2000;Schumacher, Elston, & D'Esposito, 2003).…”

“…Stimulus number, but not response number, was increased during recognition to identify frontal regions that may respond to increased demands on on-line visual search and processing during retrieval. In addition, by including the recognition task we were able to ascertain which frontal activations were related to domain-specific retrieval-related control processes, such as familiarity-based retrieval monitoring (Dobbins, Rice, Wagner, & Schacter, 2003;Dudukovic & Wagner, 2007).…”

“…To do so, we used the following operational definition for temporal context retrieval tasks: temporal context retrieval tasks involve (i) recognizing the presented stimuli as previously seen (EM retrieval) (ii) maintaining the retrieved mnemonic information in working memory (WM) (iii) the strategic ordering of stimuli, based either on the recollected temporal information or weighted feelings of relative familiarity, (iv) the attentional selection of stimuli, stimulus-response mapping, which inherently involves response selection (collectively referred to as "selection" processes in this paper) and (v) stimulus-guided responding (referred to as " motor control" processes) (Koechlin, Ody, & Kouneiher, 2003;Moscovitch, 2002;Rajah & McIntosh, 2006;Rowe & Passingham, 2001)). This operational definition does not specify if temporal context retrieval involves temporal recollection or familiarity-based retrieval (Dobbins, Rice, Wagner, & Schacter, 2003;Yonelinas, Otten, Shaw, & Rugg, 2005). Instead, the focus of the current operational definition is on cognitive control processes.…”

Does lateral parietal cortex support episodic memory?

“…Wagner et al (2005), following Rugg and colleagues' lead (e.g., Rugg & Wilding, 1996) pointed out that in at least some lateral parietal areas, activation tends to be greater when participants are required to retrieve information about the specific contextual details associated with an event, such as remembering which of two actions one performed in relation to a stimulus at encoding (Dobbins, 2003) or in which spatial location a stimulus was studied (Cansino et al, 2002; see also Hayes et al, 2004). This possibility also fits with classic interpretations of the heteromodal role of parietal cortex, in which it posited to act as a crossroads, integrating information from multiple sensory domains (Critchley, 1953).…”