Subiculum: parts and functions of this brain structure

The hippocampus is one of the oldest parts of the brain; it is believed to have been at work in our ancestors for hundreds of millions of years. It is a biological structure known to be very involved in the functioning of memory. Our own individual identity, as well as our ability to learn, depends on it.

The hippocampal formation, which is the region formed by the hippocampus and a series of neighboring structures, is not functionally homogeneous; it has several parts that deal with different things. The subiculum is one of them, and it has a very special role in the functioning of memory, as has recently been discovered.

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What is the subiculum?

The subiculum is a part of the brain located in the lower part of the hippocampal formation, with one of the latter in each of the cerebral hemispheres. It is formed mainly by gray matter, since in this anatomical region the bodies of neurons that connect with neural structures such as the amygdala or the hypothalamus.

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Its functions

Although not much is known yet about the exact operation of the sub-curriculum, it is generally associated with two functions: the memory processing of the memory system that involves different parts of the brain, and the processing of spatial and movement information, relative to the space that objects occupy at a given moment. In addition, it is believed to play an important role in epileptic seizures.

Your memory workings

Until a few years ago, it was believed that human memory worked in the following way. When experiencing an experience, a representation of this is "registered" by the networks of neurons that make up the hippocampus. This brain structure would be in charge of making possible the short-term memory processing of this experience; That is, when we remember that information minutes, hours or a few days after having memorized it, the hippocampus would be the part of the brain that retrieves the data.

However, over time that memory passes from short-term memory to long-term memory, and with this transition would also come a “migration” of the data stored in the brain: they would pass from the hippocampus to other parts of the brain, distributed among the frontal, temporal and parietal lobes of each hemisphere.

However, a few years ago it was discovered that this is not how memory works, and that the subiculum plays a very important role in memory.

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The subiculum as a store of short-term memory

As recent studies carried out with techniques to illuminate parts of the brain in real time have shown more activated at each moment, when we live a new experience, its memory passes from the hippocampus to two parts of the brain. It is “archived” in two copies that work in parallel, with relative independence one from the other. The short-term memory is stored in the subicule, and the long-term memory remains in the cortex of the frontal lobe, but remains "deactivated", latent.

At first, it is the copy of the memory stored in the subiculum that makes us able to evoke these experiences shortly after having lived them. However, as the days go by, this copy disappears, and the memory stored in the front part of the brain's cortex begins to be activated.

So this process establishes that the functioning of the processing of memories follows two differentiated routes, instead of following a sequence in which the memory physically travels from one specific place in the brain to another. There is a part of the memory that remains silent and that, only if certain conditions are met, does it manifest itself.

Parts of the subiculum

The subiculum can be divided into several structures. They are as follows.

1. Presubicle

This is the area through which information from the hippocampus enters. This linked to memory and movement processing.

2. Postsubicle

This part of the subiculum contains neurons responsible for focusing the face in a certain direction, allowing its location to correspond to certain objectives.

3. Parasubicle

This part of the brain contains network cells, which are neurons that fire when we perceive certain movements and register them as such.

4. Prosubicle

Little is known about this region, although it has been seen that it may play a role in the appearance of anosognosiain cases of Alzheimer's disease. Furthermore, in this area of ​​the brain the neurons are somewhat smaller and are distributed in a more compact and dense formation than in most other similar regions.