The Role of Consolidation in Conceptual Memory

Concepts allow us to bring meaning to the world; they require the integration of information from across multiple episodes and events, and the abstraction of statistical patterns and regularities from both new and existing knowledge. Processes during consolidation have been shown to benefit the extraction of gist, the detection of hidden rules and the integration of memory elements into coherent representations. Consolidation may therefore play an important role in the development of conceptual memory.
To explore this, we used a range of consolidation delay manipulations and two paradigms that assessed the development of concept-based representations. In Chapter 2 and 3 we used an abstract cross-modal information-integration categorisation task, which allowed us to investigate the integration of information from across modalities (visual and auditory) and the extraction of an underlying category structure. In these experiments we did not find any immediate consolidation benefits on categorisation performance. However, post-consolidation improvements in category learning were observed, if participants had a sleep-filled delay; suggesting that processes during sleep may enhance the effectiveness of future concept-based learning. In Chapters 4 and 5, we used an associative memory task that allowed us to dissociate the impact of consolidation on generalised concept-based representations from trained item knowledge. In this task we found sleep-associated improvements in memory; however, these were specific to trained-item knowledge, with no sleep-associated benefits in measures of memory generalisation. An investigation into intrinsic brain connectivity in Chapter 5 suggests that general variations in functional connectivity can in part explain individual differences in long-term memory performance; with decoupling between heteromodal and sensory-motor brain regions supporting memory generalisation and the formation of concepts. Our results provide new insights into the role of consolidation in the development of conceptual memory and highlight important directions for future research.