Although the positive impact of sleep on cognition has long been recognized, Baycrest researchers have shown that a good night’s sleep can actively improve the memory instead of easy protecting against decline. The new findings are the first to reveal that sleep helps us to better remember the order of events in our lives, even after more than a year.
“Hoewel ons geheugen voor functies zoals objectgrootte en kleur in de loop van de tijd afneemt, kan slaap ons geheugen verbeteren voor evenementenreeks, zegt Dr. Brian Levine, senior wetenschapper van het Rotman Research Institute, onderdeel van de Baycrest Academy for Research and Education (Bare) en senior auteur van deze studie, getiteld” Sleep Selectief en duurzaam verhoogt het geheugen voor de reeks van realtsen Nature human behavior. “This study deepens our understanding of how critical sleep is for integrating experiences in memory.”
Most studies on human memory for events require that participants remember items, such as words or images, in a laboratory environment. In this study, Dr. Levine-Along, however, Dr. Nicholas B. Diamond and Dr. Stephanie Simpson designed, a unique and compelling real-world experience in a 20-minute audio-guided tour through artworks that are represented in Baycrest, a global leader in aging and brain health in Toronto, Ontario. Participants took the tour and were tested for their memory with five delay intervals ranging from one hour to 15 months after the Tour. The tests contain questions about the physical characteristics of the artwork and the successive order of touring items. The researchers discovered that sleep increases the memory for sequences, while the memory for functions decreased.
To confirm their findings, they conducted a second study in which participants were randomized to a wake group or a sleeping group. The sleeping group did the Tour and the first memory test in the evening and the second memory test after a night of sleep in a sleeping laboratory with brain activity monitored with Elektro -Falography (EEG). The Wake Group did the tour and the first memory test in the morning and the second memory test in the evening after normal daily activities. To test the long -term effects of sleep at the memory, both groups completed a week, a month and 15 months after the Tour, a week, a month and 15 months.
Main research results:
- Sleeping -enhanced memory for the order of the Tour items (sequences), but no memory for functions.
- The advantage of sleep versus wake for sequential memory was clear after a single night of sleep, and this advantage kept at all test points, including 15 months later.
- Such an improvement was not found for memory for characteristics of the Tour items, such as shape and color, which continued to fall over time.
- Recordings of brain activity in the sleep laboratory showed that specific brain waves during deep sleep – namely slow waves and spindles – were linked to overall memory improvement.
Good sleep is an essential part of a healthy lifestyle, including for the brain and cognition. This study shows how deep sleep benefits the memory for the successive structure of everyday events, even when the specific details of those events fade away with time and points to a possible cause of memory changes in older adults who live with dementia. “The benefits of sleep in memory are powerful; only one night makes a difference that lasts for a year,” said Dr. Levine.
This study was funded by the Canadian Institutes of Health Research.