PT  - JOURNAL ARTICLE
AU  - Adrien Conessa
AU  - Ursula Debarnot
AU  - Isabelle Siegler
AU  - Arnaud Boutin
TI  - Temporal clustering of sleep spindles for motor skill consolidation and generalizability following learning by physical practice, motor imagery and action observation
AID  - 10.1101/2022.12.06.519290
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.12.06.519290
4099  - http://biorxiv.org/content/early/2022/12/06/2022.12.06.519290.short
4100  - http://biorxiv.org/content/early/2022/12/06/2022.12.06.519290.full
AB  - Sleep benefits the consolidation of motor skills learned by physical practice, mainly through periodic thalamocortical sleep spindle activity. However, motor skills can be learned without overt movement, either through motor imagery or action observation. Here, we investigated whether sleep spindle activity also supports the consolidation of non-physically learned movements. Forty-five electroencephalographic sleep recordings were collected during a daytime nap after motor sequence learning by physical practice, motor imagery or action observation. Our findings revealed that irrespective of the modality of practice, spindles tend to cluster in trains on a low-frequency time scale of about 50 seconds, and during which spindles iterate every 3-4 seconds. However, despite this apparent modality-unspecific temporal organization of sleep spindles, different behavioral outcomes were elicited. We show that a daytime nap offers an early sleep window that promotes the retention of the learned motor skill following PP and MI practice, and its generalizability towards the transfer of skill from one effector to another after AO practice. Altogether, we demonstrated that the temporal cluster-based organization of sleep spindles may be a general mechanism for effective memory reprocessing.Competing Interest StatementThe authors have declared no competing interest.