The hippocampus is one of the most important structures of the brain. A special feature is that each half of the brain (hemisphere) has its own hippocampus. This acts as a central switching station.
What is the hippocampus?
Hippocampus is a Latin word and has the meaning of the seahorse. As early as 1706, a certain similarity of the brain part with a seahorse has been noticed. However, at that time people were not aware of the role played by the hippocampus. It was only over the centuries that the brain part was given a high status. Specifically, it is a connection point between short-term memory and long-term memory. As an interface, the hippocampus receives a variety of information. These originate from sensory systems that receive stimuli from the environment. In the foreground are sensory impressions, first and foremost sight, hearing and taste. The task of the hippocampus is now to make a selection. Specifically, stimuli are assigned a relevance depending on their intensity and urgency. Of the abundance of information, only a fraction is passed on. In the applicable brain areas, processing and storage take place last.
Anatomy and structure
The hippocampus is located in the telencephalon, also known as the end brain. This in turn is part of the central nervous system and is the largest section in the brain. The hippocampus itself is divided into three structures:
The dentate gyrus, the cornu ammonis, and the subiculum. The first structure, the gyrus, acts as the input station. This is where all the information passed on by the sensory organs comes together. In the gyrus there are so-called interneurons, which take over an inhibitory function. In this way, the intensity of the stimuli is regulated. The next section is the cornu ammonis. Colloquially, it is called the ammonic horn. At this point, the actual selection of information takes place. Finally, the subiculum is responsible for the specific subdivision and transmission. In addition, the hippocampus consists of numerous connections. These are essential for proper communication within the hippocampus and to neighboring areas. Damage to the connections can lead to momentous impairments.
Function and tasks
The transfer of information from short-term memory to long-term memory is the most important task of the hippocampus. However, the junction is not responsible for specific storage. In medical circles, it is instead seen as an interface that generates new information. Information that already exists remains unchanged. In addition, the interface fulfills the function of coordinating existing memory content. This is illustrated by the example of the hometown. If one tries to design a map of the hometown, impressions from different times and places come together. The hippocampus is now responsible for bringing the impressions together. As a consequence, people succeed in orienting themselves in a familiar city. In science, this is referred to as location memory. Finally, an important task is to distinguish information according to its variation. Colloquially, one speaks of the novelty detector. The idea is based on the fact that information does not have to be stored if it already exists. Instead, the relevance of this information is increased. As a result, it can be retrieved more easily. Something similar happens when an already known piece of information is slightly varied. This information is not created again. Instead, the already existing information is changed. This has the advantage that confusion is avoided. Here, the memory trace is also stabilized. Furthermore, the hippocampus plays an important role in the processing of emotions. This can be attributed to the distinct connections to the amygdala, the fear center. Together with the amygdala, we manage to feel joy, sadness or fear intensely. However, this also has an effect on the hippocampus itself. Thus, negative stimuli with high intensity can even lead to a reduction of the brain structure. The regression of the hippocampus could be observed especially in depression and anxiety disorders. As a result, emotions were felt more weakly.
Diseases and disorders
Damage to the brain structure can lead to momentous limitations.Degradation processes, such as those that occur in dementia, are particularly problematic. Specifically, dementia results in a decline in mental abilities. This affects thinking, remembering and orientation. In the advanced stages, patients are no longer able to perform everyday activities independently. There is currently no cure. However, early treatment succeeds in delaying the course of the disease. The average life expectancy is seven years. In addition, the hippocampus is related to epilepsy. Researchers have recognized that changing hippocampal formations may promote the onset of epilepsy. It is possible that the changes are favored by alcohol or drug abuse. Epilepsy is a brain disease that causes seizures. A seizure can last a few seconds or even several minutes. It is manifested by muscle twitching and a loss of consciousness. This is accompanied by convulsions and twitching. However, with targeted medication, it is possible to reduce the risk of another seizure. Last, experts suspect that drug use during childhood can have a negative effect on the formation of the hippocampus. This is thought to affect cognitive performance even in adulthood. For example, a malformation can worsen memory and spatial orientation. In addition, emotions are felt more weakly, while new information is not assigned appropriate relevance. Last, malformation can lead to deteriorated coordination of brain areas.
