Thesis defense Eelco Vincent van Dongen (Donders Series 116)

May 17, 2013

Promotors: Prof.dr. G. Fernández, Prof.dr. D.G. Norris, copromotors: Dr. M. Barth, Dr. A. Takashima

Sleeping to remember. On the neural and behavioral mechanisms of sleep-dependent memory consolidation

Sleep is important for the consolidation of declarative memories. The neural and behavioral mechanisms that mediate its role in long-term memory retention are, however, largely unknown. Eelco van Dongen investigated and manipulated the sleep-dependent memory consolidation process in the brain during concurrent electro-encephalography (EEG) and functional magnetic resonance imaging (fMRI) recordings. His findings demonstrate that offline memory consolidation during sleep is an active process that adaptively organizes our memories. The neural correlates of this process were mainly found in brain areas critical for encoding and retrieval during wake. These results provide some evidence for the theory that sleep facilitates memory retention through neural replay or reactivation of recent experiences. Importantly, although the sleep-dependent consolidation process occurs naturally, it is sensitive to outside intervention. Van Dongen’s results show that memory and its neural correlates can be modulated using targeted reactivation during sleep and the expected future relevance of learned information. Offline consolidation during sleep is therefore a promising target for a variety of educational, clinical and scientific applications. Overall, this thesis demonstrates that sleep-dependent memory processes have a clear function: they make sure our memory is properly organized, and that  relevant memories are retained while irrelevant memories are forgotten.