Recent research conducted at the National Academy of Science has demonstrated that memory and sleep are intrinsically connected, and that broken sleep affects our ability to store memories.
The research has helped to explain how memory problems are caused in medical conditions like sleep apnea and Alzheimer's.
The Stanford University research, conducted among mice, showed that mice that went through disturbed sleep were not able to recognize objects they were previously aware of.
It is hypothesized that sleep is a method by which the body sifts through memories acquired during the day, deciding on the specific memories it needs to keep and those that can be discarded. However, without proper sleep the mice couldn't detect objects that needed to remember.
The study used a technique called optogenetics, whereby specific types of brain cells are genetically engineered in order to control the quality of sleep using light. Some mice were allowed to have a restful sleep, and others were subject to frequent light pulses to fragment and disturb sleep.
It was observed before the experiment that when a familiar object and a new object were placed in a box with the mice, they tended to explore the new object and ignore the one they were familiar with.
The mice given a restful sleep acted in exactly the same way when presented with objects after the experiment – clearly having boosted memory through sleep. However, in the case of mice subjected to disturbed sleep, the mice explored the objects with equal attention and apparent memory loss.
Dr. Neil Stanley, an independent expert on sleep and former chairman of British Sleep Society, believes that during the day we accumulate memories, and that we need to sort and organize them at some time to ‘lock down’ the ones that we want to store permanently. This locking down process takes place during deep sleep.
Research such as this indicates the close connection between memory and sleep, and the importance of unbroken sleep for learning and being productive at work. To boost your memory power you need deeper, longer, more restful sleep.