If sometimes in a dream you see events from the past, then perhaps this is true for a reason. It turned out that during sleep, the brain works to consolidate and organize memories. In fact, scientists have long known that the brain needs sleep in order to revisit the events of the day and transfer them to the long-term storage of memories. This is why students are often advised to study before going to bed before the exam - to memorize the material well. However, the mechanism by which the brain stores memories is poorly understood. Recently, tiny microelectrodes placed in the brains of two epileptic patients showed for the first time exactly how neurons in the brain are activated during sleep to "replay" our short-term memories and move them into permanent storage.
Tracking individual neurons
The study, published in the journal Cell Reports, was conducted using Braingate, a collaborative device between Brown University, Stanford University and Case Western Reserve University. For the past 10 years, researchers have been developing brain-computer interfaces that allow people with amyotrophic lateral sclerosis (ALS) and other neurological diseases, traumatic brain injury, or loss of limbs to use brain signals to move computer cursors, robotic arms, and other assistive devices.
In a new study, surgeons implanted tiny electrodes in the upper brains of two paralyzed patients and asked them to think about moving their arm in a specific direction. By displaying the behavior of neurons during thinking, the decoder can translate thought into speech or action using robotic prostheses and other assistive devices.
A neuron is an electrically excitable cell that processes, stores, and transmits information using electrical and chemical signals.
As the authors of the work write, different neurons have different preferred directions. Some increase their speed whenever a person wants to move their hand up; others when a person wants to move to the right or to the left. Now, thanks to the work done, by the pattern of neuron activation, scientists can determine in which direction a person is going to move his hand.
During the experiment, two patients with implanted devices were asked to take a nap. During sleep, their neural activity was recorded as baseline. Each then played a simulated 1980s Simon electronic game in which players were asked to repeat the same order of light movements as the game just shown. Of course, both subjects did not move their limbs as Simon did. They used their minds to repeat the actions of the game - at this time the neural activity was recorded. The results showed that during daytime sleep, neuronal activity was identical to that recorded during the actual game of the two subjects. This means that their brains continued to play after they fell asleep, reproducing the same patterns in their brains.
Promotional video:
Scientists read minds
As Newsweek writes, a complete understanding of how memories are stored in the brain can help uncover how basic brain functions work. Moreover, the use of such technology to study neural activity during sleep is unprecedented. The study authors hope that in the future they will be able to develop more effective treatments for diseases that cause memory impairment, such as Alzheimer's disease.
A partially paralyzed man controls a robotic limb using the Braingate device
Let me remind you that sleep is a vital process in which researchers have been trying to understand for more than a century. So, just three years ago, the general public became aware of circadian rhythms - rhythms with a period of about 24 hours, which all living beings on Earth have and which - including - are responsible for the time of sleep and wakefulness. And my colleague Artem Sutyagin wrote a detailed and fascinating material about the reasons why people generally have dreams. I highly recommend reading.
In concluding this article, I cannot but mention that the study is not without limitations: only two patients were the subjects. However, it is equally important to note that the Braingate device is generally used extremely rarely - for example, only 12 such devices have been implanted over the entire time. But be that as it may, this does not in any way detract from the fact that we are getting closer and closer to real mind reading. And even more. When do you think we will learn to read minds and where will it lead?
Lyubov Sokovikova