Cross-modal transfer of statistical information benefits from sleep

Abstract

Extracting regularities from a sequence of events is essential for understanding our environment. However, there is no consensus regarding the extent to which such regularities can be generalised beyond the modality of learning. One reason for this could be the variation in consolidation intervals used in different paradigms, also including an opportunity to sleep. Using a novel statistical learning paradigm in which structured information is acquired in the auditory domain and tested in the visual domain over either 30min or 24hr consolidation intervals, we show that cross-modal transfer can occur, but this transfer is only seen in the 24hr group. Importantly, the extent of cross-modal transfer is predicted by the amount of SWS obtained. Additionally, cross-modal transfer is associated with the same pattern of decreasing MTL and increasing striatal involvement which has previously been observed to occur across 24 hours in unimodal statistical learning. We also observed enhanced functional connectivity after 24 hours in a network of areas which have been implicated in cross-modal integration including the precuneus and the middle occipital gyrus. Finally, functional connectivity between the striatum and the precuneus was also enhanced, and this strengthening was predicted by SWS. These results demonstrate that statistical learning can generalise to some extent beyond the modality of acquisition, and together with our previously published unimodal results, support the notion that statistical learning is both domain-general and domain-specific.

Cued Memory Reactivation During SWS Abolishes the Beneficial Effect of Sleep on Abstraction

“…Durrant and colleagues 16 showed that abstraction of the underlying statistical structure was enhanced after consolidation across sleep and predicted by the time spent in SWS. SWS also predicted a trade-off between recruitment of medial temporal lobe and striatum during subsequent use of this knowledge 8 and knowledge transfer to the visual modality 11 . In short, abstraction and generalisation performance in this task clearly benefits from sleep, particularly SWS, and therefore presents a good target for cued memory reactivation.…”

“…To assess whether the effect of TMR was specific to sleep, the auditory sequence was re-presented during wakefulness directly before sleep in a third group of participants. Based on previous findings by Durrant and colleagues 8,11,16 we expected to find general overnight performance improvement, further enhanced by TMR during SWS.…”

“…Accumulating evidence suggests that these processes of statistical learning and integrative processing are facilitated by sleep [3][4][5][6][7][8][9][10] . Specifically, sleep has been shown to promote the emergence of hidden rules or underlying patterns [3][4][5]7,8 , to transfer them across modality boundaries 11 ,…”

“…Performance in the recognition task therefore reflects whether the underlying statistical structure has been abstracted and can be applied to new exemplars. Additionally, a visual version of the recall test exists, which allows to test whether regularities have generalised beyond the modality of learning 11 . Durrant and colleagues 16 showed that abstraction of the underlying statistical structure was enhanced after consolidation across sleep and predicted by the time spent in SWS.…”

“…We used an auditory statistical learning task, for which the benefit of sleep and the association between abstraction performance and SWS is well established 7,8,11 . In this task participants are exposed to a sequence of tones that is probabilistically determined.…”