Seeking to further understand sleep and waking, University of Rochester in New York scientists have been exploring brain chemistry (the neurobiology of sleep.) It has long been established that sleep relates to neuron activity, with neurons switching down the power to parts of the brain in order for someone to go to sleep, and then re-activating in order to wake someone up.
However, it now seems that this process is not simply electrical. According to Science for Students, this requires chemical processes to control the rate of neural activity. Variations to these chemicals, as shown with studies using mice, can be used to artificially induce sleep or wakefulness.
The chemical processes relate to variations in the types of ions (electrically charged molecules) and their concentrations in the brain. The ions involved are potassium, calcium and magnesium.
By looking at ion variation, the scientists found levels of potassium ions are high when mice are awake. In contrast, levels of calcium and magnesium ions are higher when a mouse is asleep. It is though the same effect happens with people, although this needs further study.
To show how varying the chemical cocktail affects the states of sleepiness and wakefulness, the scientists varied the concentration of ions in the brains of mice and found they could induce either state. Importantly, the chemicals could switch on or off neurological activity. This confirmed that the chemicals act as neuromodulators.
A second round of research found that mice that have been anesthetized could be raised from a coma like state. This opens up a potential new area of research for dealing with people who have been rendered unconscious. In the short term, the findings could help those who have been anesthetized recover more easily, minimizing the ‘groggy’ state through boosting the levels of calcium ions and magnesium ions.
The research was led by Dr. Maiken Nedergaard and the findings have been published in the journal Science. The research paper is headed “Changes in the composition of brain interstitial ions control the sleep-wake cycle.”