Scientists have discovered that navigational brain cells, which aid humans in having a “sense direction” when we are awake, remain electrically active when people are in deep sleep. This information may turn out to be important for medics treating treating navigational problems. Moreover, the loss of the sense of direction and place are some of the first major symptoms of Alzheimer’s disease, as well as being associated with other related neurological disorders.
This new finding has come from research conducted using mice. The outcome was that head direction neurons continue to code for the “virtual” direction of their gaze during sleep. Furthermore, with Rapid Eye Movement (REM) sleep (when the most intense dreaming occurs) the neuron activity that affects the brain’s compass functions at the same speed as it does when a person is awake. This finding was the output of a two-year period where the scientists videotaped the head movements of mice and simultaneously recorded the electrical activity in the head-direction regions of the sleeping animals.
This finding shows the brain’s efforts to actively explore and coordinate its operations even when it disengages from its interactions with the environment (that is, when a person falls asleep.)
In terms of future work in relation to conditions like Alzheimer’s, the research group want to establish how important this activity is. They plan to run experiments to examine if head direction and navigation can be electrically controlled and predicted in advance. The outcome of this could open up a new arena for examining neurodegenerative diseases.
The research was undertaken by scientists based at the NYU Langone Medical Center. The findings have been published in the journal Nature Neuroscience. The research paper is called “Sleep, Memory & Brain Rhythms.”
