Introduction to Sleep and Memory
What is the purpose of sleep? Though scholarly speculation about sleep dates back to the Greeks and Romans, scientific theories based on experimental data have only recently emerged. In recent years a new hypothesis has received increasing attention: Sleep actively functions to consolidate recently-formed memories.
Early research concluded that the memory benefits of sleep were either a mistake (Ebbinghaus, 1885) or that sleep passively protects individuals’ memory from interference (Jenkins & Dallenbach, 1924). However, with the development of polysomnography and the discovery of various stages of sleep, sleep could no longer be viewed as a passive and invariant state of brain activity and consciousness. In the 1960-70s, Bruce Ekstrand and colleagues observed that different stages of sleep were associated with
Sleep, Memory, and Aging Research
Most sleep-dependent memory consolidation research has examined sleep and memory in college-aged adults, ignoring how Fox News.
Sleep and Cognitive "Training" Research
Many researchers and clinicians are interested in whether cognitive abilities can be trained. Our research suggests that high quality sleep following an initial "training" phase might facilitate training on a working memory task (Scullin, Trotti, Wilson, Greer, & Bliwise, 2012, Brain). We observed that dopamine-treated Parkinson's disease patients demonstrated "offline" gains in a working memory task after a night of sleep. Such sleep-dependent improvements, as illustrated to the right, were strongest when patients had a lot of slow wave sleep and when they showed no signs of sleep apnea. These results provide clear evidence that the type of sleep obtained during a training interval can be associated with either the facilitation or the blocking of cognitive training.
You can read the news release for this research here. For more information on my research on sleep and cognitive training see this powerpoint presentation.
Sleep and Prospective Memory Research
Sleep has been demonstrated to actively benefit memory for previously learned information ("retrospective memory") in college-aged adults, but there has been little research on whether sleep also benefits prospective memory, which is the memory you use for initiating future events. In a previous project (Scullin & McDaniel, 2010, Psychological Science) we tested prospective memory performance across delay intervals that included nocturnal sleep or daytime wake and found that sleep following forming a prospective memory intention led to greater prospective remembering during a test context that was originally temporally associated with the prospective memory intention. In a sense, sleep reinforced in memory a context in which the prospective memory goal was to be executed. A critical, unanswered question concerns which aspect of sleep (e.g., slow wave sleep) may be associated with benefits to prospective memory, and particularly with the reinforcement of the context--intention link.
You can read the news release for this research here. For more information on my research on sleep and prospective memory, see this powerpoint presentation.