A lot of people know from experience that a bad night’s sleep can affect your day in a negative way. Up until now, however, the casual relationship between sleep deprivation and learning efficiency has not been proven. Thanks to researchers from the Swiss University of Zurich, we’re one step closer to unraveling this mystery. Their published article in Nature Communications proves that sleep deprivation in a certain brain area impairs the ability to perform certain motor tasks.
But first, back to the basics. For humans, 8 hours of sleep per night is ideal. During the night, we enter certain sleep cycles. These sleep cycles can be divided into ‘REM’ (Rapid Eye Movement) and ‘NREM’ (Non-Rapid Eye Movement) sleep. In the early phases of the NREM sleep, movement of large amounts of neurons can be detected as ‘slow waves’ by an electroencephalogram (EEG). This is also called the ‘deep sleep’ phase. The current theory is that these slow waves are needed for the brain to be able to rest.
With this physiology in mind, the researchers developed a special technique to deprive the motor cortex from sleep. They let participants learn a couple of movements (controlled by the motor cortex), and let them have a good night’s rest. The following day, they taught the subjects something else and measured their learning curve.
During the night, they put electrodes on the heads of the participants. This allowed them to measure the activity of the slow waves in the motor cortex. They then disturbed the slow waves sent out by the neurons in this area by applying acoustic waves. The next day, they let the subjects execute some other movements. The study subjects showed a lesser ability to learn motor movements the day after the slow waves were disturbed.
By showing that disturbance of these slow waves leads to an impaired learning ability, this research confirms that local deep sleep is needed for the brain to be able to learn new motor movements.
So, if you want to stay focused and have a sharp learning ability the next day, be sure to get that much-needed deep sleep!
Resources:Fattinger, S. et al. Deep sleep maintains learning efficiency of the human brain. Nat. Commun. 8, 15405 doi: 10.1038/ncomms15405 (2017). https://www.nature.com/articles/ncomms15405#abstract