Sleep Enhances Consolidation of Memory Traces for Complex Problem-Solving Skills

• Published in: Cerebral cortex (New York, N.Y. 1991) Vol. 32; no. 4; pp. 653 - 667
• Main Authors: van den Berg, N H, Pozzobon, A, Fang, Z, Al-Kuwatli, J, Toor, B, Ray, L B, Fogel, S M
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 08-02-2022
• Subjects: Hippocampus - diagnostic imaging; Humans; Learning - physiology; Memory Consolidation - physiology; Motor Skills - physiology; Sleep - physiology; Wakefulness - physiology; sleep; procedural memory; fMRI, memory consolidation; problem solving
• ISSN: 1047-3211; 1460-2199
• DOI: 10.1093/cercor/bhab216

Abstract
Sleep consolidates memory for procedural motor skills, reflected by sleep-dependent changes in the hippocampal-striatal-cortical network. Other forms of procedural skills require the acquisition of a novel strategy to solve a problem, which recruit overlapping brain regions and specialized areas including the caudate and prefrontal cortex. Sleep preferentially benefits strategy and problem-solving skills over the accompanying motor execution movements. However, it is unclear how acquiring new strategies benefit from sleep. Here, participants performed a task requiring the execution of a sequence of movements to learn a novel cognitive strategy. Participants performed this task while undergoing fMRI before and after an interval of either a full night sleep, a daytime nap, or wakefulness. Participants also performed a motor control task, which precluded the opportunity to learn the strategy. In this way, we subtracted motor execution-related brain activations from activations specific to the strategy. The sleep and nap groups experienced greater behavioral performance improvements compared to the wake group on the strategy-based task. Following sleep, we observed enhanced activation of the caudate in addition to other regions in the hippocampal-striatal-cortical network, compared to wakefulness. This study demonstrates that sleep is a privileged time to enhance newly acquired cognitive strategies needed to solve problems.