Recently, researchers of the University of Zurich and Swiss Federal Institute of Technology in Zurich have validated the causal context of why deep sleep is critical to the efficiency of the human brain in learning. They have advanced a brand new, non-invasive technique for modulating deep sleep in humans in a targeted vicinity of the brain.
Most people recognise from their very own experience that only a single sleepless night can lead to trouble in focusing on mental activities the day after. Researchers expect that deep sleep is essential for maintaining the learning efficiency of the human brain in the long run. While we are wide awake, we continuously acquire impressions from our environment, whereby several connections between the nerve cells — known as synapses — are excited and intensified at times. The excitation of the synapses does not normalize again till we doze off. Without a recovery segment, many synapses remain maximally excited, this means that modifications in the body are not possible and learning efficiency is blocked.
The Connection between Deep Sleep and Learning
The connection between deep sleep and learning performance has long been acknowledged and established. Now, researchers on the University of Zurich (UZH) and the Swiss Federal Institute of Technology (ETH) in Zurich have been capable of displaying a causal connection in the human brain for the first time.
Reto Huber, professor at the University Children’s Hospital Zurich and of Child and Adolescent Psychiatry at UZH, and Nicole Wenderoth, professor in the Department of Health Sciences and Technology at the ETH Zurich, have succeeded in manipulating the deep sleep of subjects in focused regions. Huber commented, We have developed a method that lets us reduce the sleep depth in a certain part of the brain and therefore prove the causal connection between deep sleep and learning efficiency.
Sleep Quality Was Not Impaired
In the experiment which was divided into two parts with six women and seven men, the test subjects had to master three distinctive motoric tasks. The concrete undertaking was to analyze diverse sequences of finger actions throughout the day. At night, the brain activity of the subjects all through sleep was monitored with the aid of EEG. While the subjects have been able to sleep without disturbance after the studying segment on the primary day, their sleep was manipulated in a centered way on the second day of the test with the use of acoustic stimulation in the course of the deep sleep phase. To accomplish that, the researchers localized exactly that a part of the mind responsible for mastering the abovementioned finger movements, such as the control of motor skills (motor cortex). The subjects do not know this manipulation; to them, the sleep quality of both experimental stages was still the same day after day.
Disturbances in Deep Sleep Negatively Affects Learning Efficiency
In a second step, researchers tested how the manipulation of deep sleep affected the motoric learning tasks on the next day. Here, they determined how the learning and performance curves of the subjects modified over the direction of the test. As expected, the subjects have been especially able to analyze the motoric challenge well within the morning.
As the day went on, however, the rate of errors rose. After sleep, the learning performance extensively improved again. This becomes no longer the case after the night with the manipulated sleep phase. Here, clean overall performance losses and problems in learning the finger movements have been discovered. Learning performance was as weak as on the evening of the primary day of the test. Through the manipulation of the motor cortex, the excitability of the corresponding synapses was not reduced at some point of sleep. Nicole Wenderoth commented, In the strongly excited region of the brain, learning efficiency was saturated and could no longer be changed, which inhibited the learning of motor skills.
In a controlled test with the equal assignment challenge, researchers manipulated another site of the brain all throughout sleep. In this situation, however, this manipulation had no impact on the mastering performance of the subjects.
The newly received knowledge is a critical step in researching human sleep. The goal of the scientists is to apply this know-how in medical research. According to Reto Huber, Using the new method, we hope to be able to manipulate those specific brain regions that are directly connected with the disease.