Odor Cues During Slow-Wave Sleep
Prompt Declarative Memory Consolidation
Rasch, B., Buchel, C., Gais, S., & Born, J.
Presented by:
Suiki Zhang

 sleep facilitates the consolidation of newly acquired memories for long-term storage
 Consolidation of hippocampus-dependent memories benefits particularly from slowwave sleep (SWS)
 Odours are excellent contextual retrieval cues for various types of memories

 Purpose: used an odour to reactivate memories in human during sleep
 Hypothesis: odour-induced reactivations boosting the consolidation of hippocampusdependent declarative memories are related to hippocampal activity during SWS

 18 participants
 Olfactory stimulus = smell of a rose
 Learned a 2D object location task (locations of 15 card pairs on a computer screen) & a procedural finger-tapping task in the evening before sleep
 4 different conditions

 Re-exposure to the odour during SWS improved the retention of hippocampusdependent memories but not of hippocampus-independent procedural memories
 Odour re-exposure was ineffective during
REM sleep or wakefulness or when the odour had been omitted prior learning

 Odour cues activate the hippocampus during
SWS to a much greater extent than during wakefulness
 Supports the theory that memory consolidation evolves from repeated reactivation of newly encoded hippocampal memory during SWS  eventually leads to transfer of the memory to cortical regions for long term storage

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 Strengths:
Clear diagrams/graphs
Interesting study
 Weaknesses:
- unorganized; no headings for sections
 Next steps:
- Examine whether the type of the odour would have different effects

 Rasch, B., Buchel, C., Gais, S., & Born, J.
(2007). Odor cues during slow-wave sleep prompt declarative memory consolidation.
Science magazine, 315, 1426-1429.