Competition and Cooperation among Relational Memory Representations

Abstract

Mnemonic processing engages multiple systems that cooperate and compete to support task performance. Exploring these systems’ interaction requires memory tasks that produce rich data with multiple patterns of performance sensitive to different processing sub-components. Here we present a novel context-dependent relational memory paradigm designed to engage multiple learning and memory systems. In this task, participants learned unique face-room associations in two distinct contexts (i.e., different colored buildings). Faces occupied rooms as determined by an implicit gender-by-side rule structure (e.g., male faces on the left and female faces on the right) and all faces were seen in both contexts. In two experiments, we use behavioral and eye-tracking measures to investigate interactions among different memory representations in both younger and older adult populations; furthermore we link these representations to volumetric variations in hippocampus and ventromedial PFC among older adults. Overall, performance was very accurate. Successful face placement into a studied room systematically varied with hippocampal volume. Selecting the studied room in the wrong context was the most typical error. The proportion of these errors to correct responses positively correlated with ventromedial prefrontal volume. This novel task provides a powerful tool for investigating both the unique and interacting contributions of these systems in support of relational memory.

Dynamic Hippocampal and Prefrontal Contributions to Memory Processes and Representations Blur the Boundaries of Traditional Cognitive Domains

“…Recently, the role of uncinate fasciculus integrity in memory-guided decision-making was evaluated in a task designed to rely on contributions from both the hippocampus and PFC. The task was a relational memory task that also incorporated implicit, abstract rules, which could be learned across trials to facilitate performance [ 113 , 114 ]. Responses were made based on a combination of relational memory and implicit rule use.…”

“…Other theories, which primarily emphasize hippocampal–PFC contributions to memory, do incorporate the nature of hippocampal processes and representations, building upon ideas put forth by relational memory theory. In particular, they suggest the hippocampus binds together arbitrarily co-occurring elements of experience (i.e., arbitrary relations) into a compositional representation, while areas of PFC build up more inherently meaningful relations, abstracting representations of the larger “context” in which specific memories take place (e.g., a list in which specific words appear, or a room in which a certain set of experiences tend to occur), thus aiding in context-dependent memory retrieval [ 88 , 113 , 124 ]. It has also been demonstrated that hippocampal–PFC contributions to memory formation and its use are iterative, such that: (1) new memories are integrated within existing schemas, and (2) existing schemas are further modified in the process of memory consolidation [ 88 , 125 ].…”

Structural and Functional MRI Evidence for Distinct Medial Temporal and Prefrontal Roles in Context-dependent Relational Memory

“…Such behaviors are often context dependent; for example, remembering that to visit your friend at work, you need to go to her third-floor office, but to visit her at home, you need to go to her first-floor apartment. Multiple lines of converging neuroscience research have implicated both the medial-temporal lobes (MTLs) and the pFC in various aspects and kinds of memory (e.g., Schwarb, Johnson, McGarry, & Cohen, 2016;Schwarb et al, 2015;Wang, Cohen, & Voss, 2015;Zeithamova, Dominick, & Preston, 2012;Zeithamova, Schlichting, & Preston, 2012;Battaglia, Benchenane, Sirota, Pennartz, & Wiener, 2011;Eichenbaum, Yonelinas, & Ranganath, 2007;Bunge, Burrows, & Wagner, 2004;Simons & Spiers, 2003). In recent years, understanding the unique and shared contributions of these distinct but interconnected regions has become an active and important area of research.…”

“…Exploring the engagement of these processes in a single task allows for a more direct comparison of behavioral outcomes and the neural mechanisms that support them. Therefore, in the current work, we present two experiments using a context-dependent relational memory task (Schwarb et al, 2015) designed to engage both the relational memory system and the memory-guided rule use system and also to dissociate the multiple sources of memory information that unfold over time and contribute to successful memory performance. In this task, participants learned face-room pairings in two different buildings such that room assignment was consistent with an underlying incidental contextual rule structure that could be used to guide behavior.…”

Sleep Enhances Recognition Memory for Conspecifics as Bound into Spatial Context

“…Indeed, in natural conditions social learning typically occurs embedded in a spatial context, and spatial memory is well-known to benefit from sleep (Inostroza et al, 2013 ; Oyanedel et al, 2014 ; Maingret et al, 2016 ). Moreover, memory formation in both domains shares common hippocampal circuitry, specifically in CA2 (Hitti and Siegelbaum, 2014 ; Schwarb et al, 2015 ; Alexander et al, 2016 ; Smith et al, 2016 ), rendering the possibility of interactions between the two domains occurring also during sleep-dependent consolidation. To simultaneously measure the effects of sleep on social memory and to dissociate contributions of spatial memory, we combined a standard social discrimination task with a modified radial arm maze in which the rat had direct access to both volatile and non-volatile fractions of each conspecific’s olfactory signature.…”