By Claudia Picard-Deland
Sleep is instrumental for consolidating memory and integrating new learning. A growing body of research shows that it is possible to artificially reactivate recent memory traces during sleep by replaying an auditory stimulus that was associated with the initial learning, a method known as targeted memory reactivation (TMR). Reactivating the neural networks associated with a specific memory could help reinforce and integrate these new circuits. The beneficial effects of TMR have been shown for different types of memories, including procedural memory (i.e. motor skill learning). However, it is still unknown whether TMR is efficient for whole-body procedural learning. Validating TMR in a more ecological skill learning situation is crucial in evaluating the clinical potential of this technique, for example, in physical rehabilitation.
The study conducted by Dr.Tore Nielson and Senior Doctoral student Claudia Picard-Deland and at the Dream and Nightmare Laboratory at the Center for Advanced Research in Sleep Medicine at the Université de Montréal, addresses this question by using a virtual reality setting in which participants are trained on a whole-body procedural task before taking a nap. Specifically, a room-scaled virtual reality system offers an immersive experience that involves flying and navigating in the environment to engage vestibular and motor systems. TMR is thereafter performed during the nap: sounds associated with the procedural training are softly replayed during different stages of sleep. If TMR effectively reengages and strengthens the neural circuits formed during the task, an improvement in motor performance should be observed after the nap. This procedure should help determine which stage of sleep—deep or rapid eye movement sleep—is more central to the consolidation of motor memories. Dream reports following TMR are also being analysed to assess whether kinaesthetically rich dreaming is associated with motor improvement.
The findings, if conclusive, may help in the development of non-invasive sleep-based methods for protecting or rehabilitating postural and motor functions in the face of age-related or illness-related decline. The findings, if conclusive, may help in the development of non-invasive sleep-based methods for protecting or rehabilitating postural and motor functions in the face of age-related or illness-related decline.