Memory Impaired By Interrupted Sleep
A group of researchers have arrived at the conclusion that memory can be impaired by interrupted sleep. The scientists arrived at this conclusion by using novel technology to interfere with the continuity of sleep experienced by lab mice, all other variables were kept constant. This research was published in the July issue of the Proceedings of the National Academy of Sciences in the year 2011. The team conducting this study was from the University of Stanford within the United States.
It is well documented that individuals that suffer from specific psychiatric and neurological conditions that lead to the interruption of sleep will often have problems with their memories. Among these are conditions such as sleep apnea, this is a condition in which individuals cease breathing while they sleep and may experience many mini arousals during the night. Alcohol abuse is also known to be a condition that affects sleeping patterns.
The significance of high quality sleep in the maintenance of good memory has been speculated by scientists in previous years, but any attempts to test this theory were hindered by the hardships that arise when investigations are attempted. This is because technology enabling the alteration of the continuity of sleep, while leaving other variables unchanged,, has not, until recently , been available.
This is further illustrated when scientists attempted to wake sleeping lab rats while handling them gently; they discovered that this raised the stress levels of the rats. This is another variable which had to be monitored so altering it meant scientists could not reliably check whether or not memory impairment was as a result of interruption to sleep or an increase in the stress levels of the rats.
An associate professor of psychiatry and behavioural sciences, Doctor Luis De Lecea, was one of the main leaders of this research. The doctor is presently studying the neural circuits in the brain that determine the 'wakefulness' of individuals. Lecea told the press that mice and other such rodents harbour a high sensitivity to awakenings of a physical nature, if one were to wake a rodent it will not get back to sleep for a reasonable time period, this leads to stress in the rodent.
As a result of these findings it was established that the main difficulty would be the implementation of a new method that would enable scientists to arouse important brain circuitry for extremely short lengths of time, during sleep while leaving duration and intensity of sleep unaffected. A solution to this problem was the use of 'Optogenetics'. This is the use of light in the manipulation of cells and tissues that have previously been engineered genetically to respond to pulses of light.
Doctor Lecea spoke of optogenetics as a very subtle method of sleep disturbance. The doctor and his fellow researchers wrote in their research paper that they used optogenetics aimed specifically at hypocretin and orexin neurons, these perform a significant role in the awakening process. They went on to say that they used optogenetics to activate those neurons at different time periods and were thus able to disturb sleep without affecting the intensity or duration of the sleep.
Following their treatment with optogenetics, the mice undertook a complex task in which they found themselves faced with two objects, one they had previously met while the other was new. The rodents that spent a longer period of time identifying the very same object they had previously met; this alludes to an impairment in memory.