Entorhinal Cortex, The Area Where Memory Consolidates

We have known for a long time that the first signs of Alzheimer’s disease can be seen in the entorhinal cortex. An area that connects directly with the hippocampus is aa key to understanding all processes related to episodic, autobiographical and spatial memory. It is also this structure that protects our identity and our ability to adapt to the environment.

In recent years, advances in neuroscience have brought a lot of hope. Today, it is known that the TAU protein accumulates remarkably in this region of our brain and thus favors a slow neurodegeneration. Now, studies like the one published in the Journal of Neuroscience  bring really positive data.

It was observed that the application of electrical stimulation to the entorhinal cortex favors the production of dentate granular cells, which gradually integrate into the hippocampal networks. That is, neurogenesis occurs, which tends to slightly improve the cognitive processes related to memory in these patients.

These are small advances, no doubt about it. However, nowadays strategies based on non-invasive brain stimulation are giving interesting results. Let’s look at more data on the entorhinal cortex below.

Entorhinal Cortex Functions

The entorhinal cortex is an area of ​​the brain located in the medial temporal lobe. It is often defined as an interface area, which works in constant communication with the hippocampus and neocortex. Furthermore, it is worth mentioning that it is divided into two regions: medial and lateral.

It is, in turn, a structure with multiple connections to different brain areas. It works, for example, in conjunction with the olfactory and visual pathways. It is also linked to the temporal, parietal and frontal lobes. However, as we’ve already mentioned, its main job is to be a direct bridge to the hippocampus.

In addition, it is also important to know that interest in the entorhinal cortex arose at the end of the 19th century, with Santigo Ramón and Cajal. It was during his studies to understand the functions of the nervous system that a peculiar part of the posterior temporal cortex was discovered that drew a lot of attention.

She seemed fascinating for the amount of connections she had with the whole brain. Let’s see below what their functions are.

Declarative and Spatial Memory

The entorhinal cortex is the key to consolidating two types of memory: declarative and spatial. This means that this constant connection with the hippocampus allows us, among other things, to integrate the events that make up our declarative, episodic, and semantic memory. It is in this region that our identity, our internal narrative, our personal history is carved, so to speak.

In turn, this region also helps us to orient ourselves in the space that surrounds us, to situate ourselves in any scenario.

emotional memory

As mentioned, the entorhinal cortex sends and receives information from the hippocampus, the most relevant structure of the limbic system. Let’s not forget that this area is also connected to the amygdala; therefore, it is inevitable that every memory has an emotional component.

All these processes are integrated and stored by this very relevant little structure.

olfactory center

The entorhinal cortex integrates several parts of the olfactory cortex. In the animal kingdom, and especially among predatory animals, it comprises a larger portion of the brain. But in humans and among primates, the olfactory bulb connects only 10% of its structure with the entorhinal cortex.

However, it is common to interpret that, in our case, this connection mainly facilitates the olfactory memory. We make a lot of connections with certain facts from the past and their particular scents.

The entorhinal cortex and the disease

Changes in the entorhinal cortex are associated with several disorders. The best known of these is Alzheimer’s disease. Thus, the accumulation of TAU protein, together with the neurofibrillary tangles it generates, tends to appear mainly in this area.

Studies like the one carried out at Columbia University Medical Center, using functional magnetic resonance imaging, point to this place as the gateway to this devastating disease. In addition, it was also possible to prove that entorhinal decline generates cognitive failures that precede hippocampal volume reduction, something very classic in patients with dementia of the Alzheimer type.

On the other hand, there is another disease linked to the entorhinal cortex: schizophrenia. Thus, studies such as the one carried out by the University of Udine, Italy, observed a clear reduction in this area in all patients suffering from this disorder. It is especially visible in the right area, forming a prominent structural asymmetry.

To conclude, advances in understanding the architecture and functionality of our brain are, without a doubt, a very positive fact. Knowing, for example, how these very dramatic diseases relate to areas with the entorhinal cortex facilitates the development of strategies to stop their progress and improve the quality of life of patients in the future. We hope that future is not too far away.