Are spatial memories strengthened in the human hippocampus during slow wave sleep?
In rats, the firing sequences observed in hippocampal ensembles during spatial learning are replayed during subsequent sleep, suggesting a role for posttraining sleep periods in the offline processing of spatial memories. Here, using regional cerebral blood flow measurements, we show that, in humans, hippocampal areas that are activated during route learning in a virtual town are likewise activated during subsequent slow wave sleep. Most importantly, we found that the amount of hippocampal activity expressed during slow wave sleep positively correlates with the improvement of performance in route retrieval on the next day. These findings suggest that learning-dependent modulation in hippocampal activity during human sleep reflects the offline processing of recent episodic and spatial memory traces, which eventually leads to the plastic changes underlying the subsequent improvement in performance.
Peigneux
Philippe
P
Cyclotron Research Center, University of Liège, B-4000 Liège, Belgium. philippe.peigneux@ulg.ac.be
Laureys
Steven
S
Fuchs
Sonia
S
Collette
Fabienne
F
Perrin
Fabien
F
Reggers
Jean
J
Phillips
Christophe
C
Degueldre
Christian
C
Del Fiore
Guy
G
Aerts
Joël
J
Luxen
André
A
Maquet
Pierre
P
D000328:Adult; D001931:Brain Mapping; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography / Q000379:methods; D004585:Electrooculography / Q000379:methods; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D017286:Polysomnography; D049268:Positron-Emission Tomography / Q000379:methods; D012815:Signal Processing, Computer-Assisted; D012890:Sleep / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology