34 research outputs found
Sleep and generalization of episodic memory
No full textVarious theoretical, computational, and empirical lines of research have indicated the significance of sleep for generalization. The two-stage model of memory (McClelland et al., 1995) suggested that recent memories are initially stored in the hippocampus and then replayed back to the neocortex for long-term storage, thereby establishing and enhancing the neuro-cortical representation of common elements (i.e., the “gist”) among different memories. Sleep is critical for this process of memory consolidation (Rasch & Born, 2013; Paller et al., 2021). Sleep is thought to enhance the integration of stimuli and abstraction of rules, and reactivation of newly learned memories during sleep could positively support both schema formation and addition to existing schemata (Lewis & Durrant, 2011). This project seeks to investigate how sleep influences the generalization of episodic memory using a memory task that has reliably shown generalization-related memory distortions.
In a series of behavioral experiments, Tompary & Thompson-Schill (2021) have demonstrated that the organization of semantic knowledge – specifically, category membership and typicality – can explain distortions in new episodic memory formation. In these experiments, participants encoded and retrieved image-location associations on a 2D grid. The locations of images were manipulated so that most members of a category (e.g. birds) were clustered near each other, but some were in random locations. We found that the retrieved locations of typical category members were more biased towards their semantic neighbors, relative to atypical members.
In the proposed experiment, we aim to test how a delay that either does or does not include sleep impacts these distortions. In this study, participants will complete the same memory procedure as described above, which concludes with an immediate memory test. This will be followed by a delayed memory test ~12 hours later. This delay will either include sleep or not, and we hypothesize that sleep will enhance consolidation and increase the likelihood of generalization-related memory distortions relative to wakefulness
Schematic memories develop quickly, but are not expressed unless necessary
No full textRaw data, analysis, and manuscript for a behavioral experiment examining the formation and expression of schematic memories
Integration of overlapping sequences emerges with consolidation through mPFC neural ensembles and hippocampal-cortical connectivity
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Integration of overlapping sequences emerges with consolidation through medial prefrontal cortex neural ensembles and hippocampal–cortical connectivity
No full textSystems consolidation theories propose two mechanisms that enable the behavioral integration of related memories: coordinated reactivation between hippocampus and cortex, and the emergence of cortical traces that reflect overlap across memories. However, there is limited empirical evidence that links these mechanisms to the emergence of behavioral integration over time. In two experiments, participants implicitly encoded sequences of objects with overlapping structure. Assessment of behavioral integration showed that response times during a recognition task reflected behavioral priming between objects that never occurred together in time but belonged to overlapping sequences. This priming was consolidation-dependent and only emerged for sequences learned 24 hr prior to the test. Critically, behavioral integration was related to changes in neural pattern similarity in the medial prefrontal cortex and increases in post-learning rest connectivity between the posterior hippocampus and lateral occipital cortex. These findings suggest that memories with a shared predictive structure become behaviorally integrated through a consolidation-related restructuring of the learned sequences, providing insight into the relationship between different consolidation mechanisms that support behavioral integration
Consolidation Promotes the Emergence of Representational Overlap in the Hippocampus and Medial Prefrontal Cortex
No full textConsolidation Promotes the Emergence of Representational Overlap Across Related Memories in the Hippocampus and Medial Prefrontal Cortex
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