In a new study, researchers out of University of California Berkley suggest that “memory triage” is at the core of the memory processing system that takes place during sleep. This triage selects the new information to remember and assimilates it into the memory areas of the brain through strengthening the memory as it was learned or finding common patterns.
In this study, the research team looked at brain images taken from 19 people who had reached retirement age as well as 18 brain images of people who were in their early 20s. The researchers found that the older group had a smaller section of the brain called the medial prefrontal cortex. This area of the brain, which is located behind the middle of the forehead, was a third smaller than the same brain area in the younger participants and was caused by the aging process.
The researchers asked all of the study participants to review a long list of words that were paired with nonsense syllables and then were tested 10 minutes later, which was prior to going to bed that night. The non-words were used to study the part of the brain that processes new information; the ability to process this type of new information declines with age.
The testing right after learning the words found that the young participants outscored the older participants by about 25 percent. The researchers then assessed the participants’ sleep and discovered that the older study participants got only 25 percent of the amount of high-quality slow-wave sleep that the younger participants did. After awakening the next morning, all participants were asked to take a second test. The results showed that the younger study participants outscored the older participants by approximately 55 percent.
Slow-wave sleep makes up approximately a quarter of a normal night’s sleep. However, older adults tend to have a harder time falling asleep and staying asleep. Furthermore, the researchers believe that structural brain changes occurring naturally as people age interfere with this type of sleep, thus making it difficult to store memories for the long term. This causes memories to remain in the short-term memory where they are then rewritten over by new memories.
So how can you get to sleep and stay asleep so that you can get more slow-wave sleep? Here are some suggestions:
- Change your sleep pattern. For instance, people who have flexible schedules or who are retired can sleep longer. Some people who have a flexible schedule also can take naps during the day. Another technique is to tightly restrict the number of hours in bed, which encourages more efficient sleep. No matter which pattern you select, stick with it and make it into a habit.
- Exercise. Regular physical activity can improve the quality of sleep.
- Don’t use technology before bed. These devices emit blue light and interfere with the body’s melatonin production.
- Maintain a calm bedroom atmosphere. Don’t keep technology in the bedroom since these devices tend to emit lights and sound. Also, maintain a dark room that is cool, which can make it easier to sleep. You can use room-darkening shades, earplugs a fan or other devices that help to make a pleasant sleeping environment.
- Be careful what you eat and drink in the evening. Eating too much or being hungry can disrupt your sleep, as can drinking too much liquid. The Mayo Clinic also warns that nicotine, caffeine and alcohol can also mess with the changes of restful sleep.
- Manage stress, which can disrupt sleep. To better manage stress, get organized, set priorities and delegate task. Find time for fun. Also the Mayo Clinic recommends writing down thoughts that are causing our mind to whirl, thus enabling you to set aside these thoughts until the next day.
Huffington Post. (2013). Sleep deprivation may be behind memory loss in elderly.
Mayo Clinic. (2011). Sleep tips: 7 steps to better sleep.
New York Times. (2013). Study links aging brain, sleep to memory decline. Houston Chronicle.
Stickgold, R. & Walker, M. P. (2013). Sleep-dependent memory triage: evolving generalization through selective processing. Nature Neuroscience.