How do our memories form? How can we remember how to get to our home or to our place of work? These functions that we perform unconsciously, without stopping to think about them, are possible thanks to brain structures such as the hippocampal formation.
Throughout the article, we will talk about this complex brain structure, the organs that make it up, and how scientific research has developed various theories about its functions.
What is the formation of the hippocampus?
In neuroanatomy, the formation of the hippocampus refers to a brain structure located in the medial temporal lobe. Although within the field of research itself there are discrepancies as to the specific organs or regions of the brain that make up this structure, most agree that at least the dentate gyrus, hippocampus, and subiculum are included in this structure. this classification. However, other areas such as the presubicle, parasubicle, and entorhinal cortex are under discussion, as not all authors recognize them as part of the formation of the hippocampus.
The main functions of the regions that make up the formation of the hippocampus are related to memory processes, navigation and spatial orientation, and control of attention.
During the nineteenth and early twentieth centuries, research on the formation of the hippocampus, more specifically the hippocampus, showed that it played a role in the olfactory system.
In addition, in 1937, research by scientists such as Papez and Klüver and Bucy began to develop the hypothesis that the formation of the hippocampus played an important role in emotional responses. However, today there is little support for the idea that these structures are directly involved in emotional processes, as emotional memory is more closely related to the amygdala.
Although it was only centuries later, the relationship between hippocampal structures and memory processes was recognized, in 1900, Russian-born neurologist Vladimir Bekhterev discovered an association between a significant memory deficit and a softening of the hippocampus and cortical tissue.
Likewise, in 1957, researchers Scoville and Milner also reported symptoms related to memory loss in patients with lesions of the medial temporal lobes. These are some of the first investigations thanks to which we now know that the formation of the hippocampus plays an essential role in certain memory processes.
Finally, animal studies conducted in 1970 also established the relationship between the hippocampus and spatial coding. However, this association is still widely debated by the scientific community.
Parts of the hippocampal formation
As stated at the beginning of the article, the hippocampal formation is made up of several brain structures. These structures are the dentate gyrus, the hippocampus and the subiculum.
1. Dentate gyrus
The convolution or dentate gyrus is part of the hippocampal formation to which it is attributed an important role in episodic memory, As well as in the exploration of new environments. In addition to the formation of memories, it is also hypothesized that the toothed torsion is involved in some way or another in the regulation of emotions.
It is believed that tooth rotation is one of the few regions of the brain in which neurogenesis occurs, that is, the birth of new neurons. It is also hypothesized that this neurogenesis facilitates or improves the formation of new memories, In addition to being associated with improved spatial memory.
Stress and depression
Other aspects in which the dentate gyrus plays a functional role are stress and depression. Some research has shown that neurogenesis increases in response to antidepressant treatment; as well as a relationship has also been established between the physiological effects of stress and the inhibition of the birth of new neurons.
Finally, it is known that the two endogenous glucocorticoids generated by stress can exert psychosis and depression, implying that neurogenesis in tooth rotation can play an important role in modulation of the symptoms of these emotional responses.
Animal studies have shown that after injury or destruction of the teeth of the dentate gyrus, it is extremely difficult to navigate a maze. Specifically, problems arise when consolidate the information learned about a specific placeThus, it is hypothesized that injuries to the dentate gyrus can cause alterations in spatial memory.
The second and most important organ in the formation of the hippocampus is the hippocampus, one of the main structures of the mammalian brain. located inside the medial or internal part of the temporal lobe.
The main functions of the hippocampus are related to both memory processes and spatial memory and orientation. Let’s see what they are.
According to the general consensus, the hippocampus is one of those in charge of the formation of new memories both episodic and autobiographical. In addition, an increase in hippocampal activity has been demonstrated in the face of the emergence of new stimuli.
Injuries in this structure usually do not affect other types of memory formation related to the acquisition of motor or cognitive skills, but they do affect the formation of new memories. That is, damage or deterioration of the hippocampus can lead to the development of anterograde amnesia.
Spatial memory and orientation
As in the dentate gyrus, animal studies have shown that certain neurons in the hippocampus they generate a series of electrical potentials when the animal passes through specific areas of its environment.
Although the evidence for this activity in primate brains is very limited, this neuronal activity may suggest that the hippocampus also has some responsibilities for spatial memory and orientation.
Finally, the structure known as the subiculum is the lower part of the hippocampal formation.
Although this structure is still under investigation, it is believed that the subiculum is involved in some cases of epilepsy. In addition, also it has been linked to working memory and spatial orientationMoreover, it is suggested that you can be involved in some addiction process.