Sleep transforms the cerebral trace of declarative memories

• DOI: 10.1073/pnas.0705454104
• Publication Date: 2007-11-14T02:05:21Z
• Authors: Steffen Gais; Geneviève Albouy; Mélanie Boly; Thien Thanh Dang-Vu; Annabelle Darsaud; Martin Desseilles; Géraldine Rauchs; Manuel Schabus; Virginie Sterpenich; Gilles Vandewalle; Pierre Maquet; Philippe Peigneux
• Keywords: Sleep; Procedural memory; Declarative memory; Engram; Long-term memory

After encoding, memory traces are initially fragile and have to be reinforced become permanent. The initial steps of this process occur at a cellular level within minutes or hours. Besides rapid synaptic consolidation, systems consolidation occurs time frame days years. For declarative memory, the latter is presumed rely on an interaction between different brain regions, in particular hippocampus medial prefrontal cortex (mPFC). Specifically, sleep has been proposed provide setting that supports such processes, leading transfer perhaps transformation memories. Using functional MRI, we show postlearning enhances hippocampal responses during recall word pairs 48 h after learning, indicating intrahippocampal processing sleep. At same time, induces memory-related connectivity mPFC. Six months memories activated mPFC more strongly when they were encoded before sleep, showing leads long-lasting changes representation level.