Last week there was a paper published in the journal Nature that got a bit of media attention because it showed that after sleep deprivation, neurons in parts of the brain fire in patterns that are observed during sleep, even when the animals were awake. These findings suggest that individual parts of the brain can go into “microsleep” or sort of shut down when an animal is sleep deprived. Now, we might imagine that this could be a protective or evolutionarily adaptive mechanism for dealing with the stressor that is sleep deprivation (although things like sleep-walking are not likely to be beneficial to a person). It could be that organisms who are able to function during microsleep might have an advantage over those who have to completely shut down and crash.
However, there is another set of experiments in the paper. When the investigators then looked at the ability of the animals to reach out and grasp a sugar pellet, they observed that microsleep in the frontal cortex (home of executive functions like attention, memory, and decision making) was significantly associated with failed attempts and impaired performance on this task. They also noted that performance actually became worse over successive training trials. The number of misses significantly increased and the behavior was more erratic and unstable over time.
The authors conclusion: “neuronal off periods…may be associated with decreased behavioural performance, as is typical of sleep-deprived individuals.”