FAQ: Sleep and Memory

7 facts about what is happening with our memories during sleep

People long ago discovered that the dream has some meaning for the memory, and expressed their understanding of the process in the proverb, "Sleep on it." Scientists after some time managed to gather evidence showing that our memory during sleep certain events occur.

• 1.Recent studies have shown that if the subjects during the experiment after learning allow some time to sleep, then this leads to a significant improvement of the memory.
  
  Many experiments have been conducted with so-called declarative memory - the memory of the kind about which we can declare that we know something. For example, subjects who come into the lab, where investigate these phenomena, the evening issued a list of unfamiliar words to them, they had to remember. They learned the words, and in the morning they were tested. And it turned out that this early test, even if they woke up very early, at 6 o'clock in the morning, shows that they remember more words than if they were immediately asked after they had learned the words. To improve memory – buy Cogitum, Semax, Piracetam, Cortexin, Pantogam and Phenotropil.
• 2.However, not all types of declarative memory. About some types of memory, we can not say or declare, as we have, for example, cycling on. This is another kind of memory, called a "motor memory". It turned out that promotes sleep, including memory and motor type. For example, in experiments the subjects were asked to remember keystroke sequence. During the experiment, you must first press the left little finger on his left hand, the middle finger on his right hand and lose a certain sequence. The subject must remember this sequence. After this sequence in practice for some time, these people can be tested. If after they have learned a certain sequence, they go to sleep in the lab, it turns out, the next morning they perform this sequence with fewer errors. But it is very clearly shown that reduced the number of errors and reduces the time during which they lose this sequence. If they had some sort of problem areas - for example, they always forget that the seventh should be such a key is pressed in such a finger - then, as a rule, these terms are improved. Subjects begin suddenly, unexpectedly do them very well.
  
  If you take the control group, which was not allowed to sleep, that is, the period of training time will be exactly the same, but one group is sleeping, and the other does not sleep, the improvement in this deprived group, which is not allowed to sleep, does not occur. Thus, the memory phenomenon after sleep improvement was demonstrated both declarative and memory on motor types.
• 3.In addition it has been demonstrated that the adoption of decisions or some interesting guesses come to us during sleep. Certainly many of these phenomena are well known. Recall that Mendeleev saw your table in a dream.
  
  In the mid-2000s. an attempt to simulate the phenomenon of insight (or insight) was made in the experiment. The subjects were given task in which they had a single sequence of numbers to generate a second sequence of numbers. We used only three digits, for example, 1, 4, 9, and 8 contain the sequence of numbers, for example, 11449494. rules generate a new sequence was simple: if the numbers are the same, you need to write the same, if different, the need to write a third. The trick is that the latest figures again generated sequence is a mirror reflection of the three that were before it. But people do not notice it, did not see this decision. Until such time as they do not see this task, the subjects went to bed. And they returned and again started to carry out this task the next morning. And it turned out that the percentage of guess about this trick people (guess performed the generation of new sequence is much faster) was significantly higher in the group allowed to sleep. The control group, which was not allowed to sleep, this improvement in time to solve this problem did not show. And interestingly, the subjects returned to the lab, began to do the task and immediately showed improvement over time. And then he said: "Oh, I see! There is such a trick, there is a mirror image. "
• 4.There is a logical question: what is happening with our memory in a dream? And in order to understand what lies behind this phenomenon, it is necessary to tell what is happening to our neurons or our brain at a time when we are asleep. It turned out that the neurons that have some behavioral specialization, i.e. exhibit an increase its activation at a time when an execution of a behavior or action, or practicing the skill - repeat its activation, that is activated again precisely during sleep.
  
  Initially this phenomenon at the neuronal level was established in rats when recording neural activity when performing the skill and a dream. The animals were offered a fairly simple task to run around the ring and collect the food in this ring, scattered randomly. Before the beginning of these experiments were well established that there neurons associated with finding a specific location in the animal, i.e. place cell. When the animal ran on the ring and gathered food, in every moment in every place this ring activated its kind of a group of neurons. Jogging on the ring meant a change of neural group to another. You are watching the change of neural activations can see without looking at the animal, the animal moves in the ring.
  
  Then the researchers continued registration of neuronal activity after the animal curled up and fell asleep after studying the situation. And it turned out that, when an animal sleeps, neural group just follow each other, as if the animal runs through this ring. Only the activation of neurons was less than at the time when it was a real jogging. But the sequence and change of neuronal groups looked such a way that it allows scientists to believe that the animal is at this moment presents itself, or sees this run or that she dreams that jogging.
• 5.In public registration of neuronal activity is possible only for medical reasons, and during sleep has not yet been evaluated. However, people can log the activity of the whole brain, for example, by functional magnetic resonance imaging or positron emission tomography. These methods make it possible to see a kind of global brain activity, because, for example, glucose uptake, or increased blood flow occurs where the higher the activity of neurons. And, accordingly, it is possible to observe the places where the most actively occurs glucose consumption or oxygen consumption in the brain. And in such experiments on humans it has been found that during sleep play, only to a lesser extent, the pattern of brain activity that was observed during the real performance of the skill.
• 6.When all that can demonstrate how some repetitive neuronal activity, and the occurrence of some other activities which were not observed at the time when there was a real training or actual reproduction of the situation. It can be assumed that for improving memory phenomenon lies reproduction of neuronal activity during sleep, and at the same time adding the activity of some other neurons, all of which leads to the fact that the groups are associated with certain types of behavior are reorganized. And they have become somewhat different. They may be more detailed, less detailed, but they are different. And the fact that these groups are not initially formed groups of neurons presumably underlies the phenomenon of memory improvement after sleep.
• 7.Open questions related to this topic, it is much more than closed. We actually do not know anything. Which neurons reproduce their activity? Obviously, not all. Obviously, the neuron less active, it generates a dream only a few action potentials, gives multiple activations. Why did he give a few activations? It is not clear. Are all the neurons that made up the group that was activated at the time of acquisition of a memory are activated again in a dream? That we do not know. It can be assumed that not all. But then the question arises as to which of them are? And why are they? Can one understand the patterns of what happens to these neuronal groups during sleep, alone, artificial neural combine these groups? If we know what to improve memory will activation of these cells, rather than those that can we artificially their activating, to create a group of neurons that has not been able to break up, and they now always be activated together and it it would lead to the existence of some kind of memory that would erase any purchase of another memory impossible? We currently do not know of such laws.