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The Hippocampus

1511 The Limbic Lobe
The hippocampus is a tiny, curved brain formation that plays a significant part in the limbic system. It remarkably resembles with the seahorse, and that’s why it is called hippocampus. The hippocampus is engaged in building new memories and is also linked to learning and emotions. You have two hippocampi because the brain is lateralized and symmetrical. They are just above each ear and within your head about an inch-and-a-half.

Hippocampus and seahorse cropped

Hippocampus and seahorse. Professor Laszlo Seressderivative work: Anthonyhcole [CC BY-SA 3.0], via Wikimedia Commons

Evolution:

The hippocampus usually appears similar across mammals from monotremes such as echidna to primates such as humans. The proportion of hippocampal size to body size rises: for primates, it is about twice the size of the echidna. However, it does not boost near the neocortex rate to the body-size proportion anywhere. Other vertebrates have areas that can be homologous to the mammalian hippocampus. Some insects and cephalopods like the octopus have a powerful capacity for spatial learning and navigation. These seem to work differently from the spatial system of mammals and have evolved independently of the mammalian system.

Function:

The hippocampus is a component of the limbic system associated with feeling and responding tasks. On the bottom of the cortex, the limbic system includes the hypothalamus and the amygdala. These structures assist in regulating various body functions, such as the endocrine system and what is frequently referred to as the "fight or flight" response.
In consolidating memories during sleep, the hippocampus also plays a part. Studies indicate that following some training or teaching experience, higher hippocampal activity during sleep leads to better memory of the material the next day.
This does not imply that long-term memories are stored in the hippocampus themselves. Instead, it is believed that the hippocampus acts as something of a shipping centre, collecting data, registering it, and momentarily storing it, before transport it off for long-term memory file and storage. In this phase, sleep is thought to play a critical role.

Hippocampus and memory:

The hippocampus plays a critical role in the formation, organization, and storage of new memories as well as linking with these memories certain sensations and feelings. In this connection, it is the hippocampus that plays a part. Research has also found that various hippocampus sub-regions themselves play significant roles in certain memory types. For instance, the hippocampus' rear portion is engaged in spatial memory processing. London cab driver studies have discovered that navigating complicated mazes of large town roads is associated with the development of the hippocampus' rear area.

Two kinds of memories:

The hippocampus enables people to process and recovers the memory of two types, declarative memories, and spatial relationships.

Declarative memories are fact and event-related memories. Examples include learning how to memorize a play's speeches or lines.

Spatial memories of the relationship require pathways or routes. For instance, they use spatial memory when a cab driver learns a path through a town. In the right hippocampus, spatial relationship memories seem to be stored.

Hippocampus and Orientation:

Neurons show activity in the rat hippocampus related to the position of the rat in its environment. As with memory theory, there is now almost universal agreement that spatial coding has a vital role to play in hippocampal function, but the details are widely discussed.

Studies of freely moving rats and mice have shown that many hippocampal neurons have "place fields," i.e., when a rat passes through a particular part of the environment, they fire outbursts of potential for action. In animals, research revealed cells with location-specific firing patterns.

Patients with drug-resistant epilepsy had their hippocampus diagnosed with electrodes. Then in a virtual reality town, a computer was used to move them around.

What happens when the hippocampus is damaged?

If one or both sections of the hippocampus are harmed by diseases such as Alzheimer's disease, or if they are injured in an accident, the individual may experience memory loss and loss of the capacity to create new, long-term memories. They may not be able to remember some stuff that happened shortly before the harm from the hippocampus, but they may still remember things that occurred long ago.

References:

https://kids.kiddle.co/Hippocampus#targetText=The%20hippocampus%20is%20part%20of,memory%20into%20long%2Dterm%20memory
https://www.verywellmind.com/what-is-the-hippocampus-2795231
https://www.medicalnewstoday.com/articles/313295.php