Why do we hardly remember our dreams?

Listening to the 'conversation' of neurons in different parts of the brain, researchers at the California Institute of Technology have taken new steps in understanding the path of formation, transformation and storage. memory storage in the brain; at the same time, answer the question of how the process of changing through different stages of sleep.

Their findings could one day help scientists understand why it is difficult for us to remember dreams.

They have long known that the memory is formed in the department code, but is stored somewhere. The highest possibility is in the neocortex - the outer layer of the brain. The process of transferring memory from one part of the brain to another requires changing the strength of the connections between neurons, depending on the exact timing of the brain cells.

Casimir Wierzynski, a Caltech graduate student in the nervous system and computer, and author of the study, said: 'We know that if the neuron A at codon shines right before the B-neuron at the new The cortex, and if there is a link between A and B, that link will be enhanced. So we want to understand the temporal relationship between neurons in the fish code and the cortex on the forehead - or the previous part of the neocortex. '

The team was led by Athanassios Siapas - a scholar at Caltech, a bioengineering department and an assistant professor of neurology and computing - who used high-tech computing and receiver technology to listen to the glow of neurons. in the mouse brain. This technique helps them identify pairs of neurons that have the same connection that they need : that is the connection that the glow of a neuron in the fish occurs just a few milliseconds ahead of the glowing of another neuron in the forehead cortex.

Wierzynski added: 'This is exactly the type of relationship needed for the coding division to make changes in the neocortex - for example, consolidating or storing memory'.

New research has taken new steps in understanding the path of memory formation, metabolism and storage in the brain; at the same time, answer the question of how the process of changing through different stages of sleep. (Photo: iStockphoto / Diane Diederich)

Once the link between neuronal neurons and forehead cortex is established, the team will use high-tech 'eavesdropping' techniques to listen to what's going on in the brains of rats. sleeping experience, since sleep has long been considered the best time to reinforce memory.

As a result, their thinking is correct, but it only takes about half the time.

The team did indeed hear the 'explosion' of neurons during sleep, but only in one phase of sleep was called shortwave phase (SWS) when deep sleep took place, There is no dream. Wierzynski said: 'It turns out that in the shortwave phase, there are periods when a lot of cells in the cod region are almost simultaneously glowing' . In response, some cells in the prefrontal cortex also glow only after a few milliseconds. 'What's interesting is that the exact time happens during this boom, not outside that time . ' On the other hand, in the rapid eye movement phase (REM) the previous neuron pairs still glow at the same speed but are no longer in harmony with each other. Wierzynski said: 'It is surprising to see that the time relationship is almost never in REM'.

Because the REM sleep phase is the phase in which the dream formed, scientists deduced that the absence of 'conversation' reinforcing the memory between neurons probably helped explain why we find it difficult to remember. dream.

Because of this curious point of view, the researchers warn that the above findings only increase opportunities, provide new research paths in the future.

Siapas said: 'We have proven that this relationship exists, we build the framework used for future research. This is a step closer to the goal of understanding the relationship between sleep and memory someday. '

Other co-authors of the study include Evgueniy Lubenov - postdoctoral biology scholar at Caltech - and Ming Gu graduate student at Caltech.

The study received support from the National Student Technical and Scientific Fellowship Center, Caltech Information and Technology Center for Biological Circuit Design, James S. McDonnell Foundation, Bren Fund, McKnight Foundation , Whitehall Foundation and National Institutes of Health.

Refer
State-dependent spike timing relationships between hippocampal and prefrontal circuits during sleep.Neuron, February 26, 2009