Rose-scented dreams improve memory

They say optimists see the world through rose-colored glasses. The positive connotations of a rose, or more specifically, its scent, also transfer to human memory. Sleeping in a rose-scented room enhances memory. Inhaling the scent of a rose while studying and then exposing yourself to the same scent while sleeping improves memory. However, this "treatment" only works for certain types of memory and only during non-rapid eye movement (NREM) sleep—a deep, non-rapid eye movement phase. Smells, the hippocampus, and memory The part of the brain called the hippocampus is thought to be like a memory pad, where we store new things we've experienced or learned. We store them there until we transfer them to long-term memory. During sleep, these memories are reactivated and migrate to the cerebral cortex. Smells, in turn, have a strong effect on the hippocampus and can therefore help trigger the process of reactivating memories, making long-term memory more efficient. Sleep in a rose-scented room Tests by Jan Born at the University of Lübeck seem to support this theory. His team exposed a group of people to the scent of roses while they memorized the positions of pairs of cards placed in a square. Half of the people then inhaled the same scent while sleeping, while the others slept without the scent. When tested the next day, those who had rose dreams matched 97% of the cards, while those who had had unscented dreams matched 86% . Slow-wave sleep and REM sleep Sleeping in a rose -scented room isn't enough. The timing of exposure to the scent is crucial. Volunteers in the aforementioned experiment had to inhale the scent of a rose during slow-wave sleep, when the hippocampus triggers recurring memories. Placing flowers under their noses during REM (rapid eye movement) sleep, when most dreams occur, didn't improve memory. Because humans quickly adapt to the scent, it had to be "switched on" and "switched off" at the appropriate times to achieve the desired effect. Different brain areas = different types of memory This olfactory trick is only useful for certain types of learning. It won't be useful for remembering skills like playing the piano or riding a bike, as these memories don't rely on the hippocampus. However, this finding may offer more user-friendly solutions to improving memory than other suggested techniques.