Hippocampus is a brain structure responsible for emotions, long term memory and spacial navigation. It is a part of the Limbic system of the brain. It is sea horse like structure situated beneath the cortex of the medial temporal lobe. In addition, hippocampus is situated in the both cerebral hemispheres as two identical pairs.
What are the functions?
Earlier it was thought to have a role in perception of smell. But this belief is later found to be false. However several studies have found a correlation between hippocampus and memory of smell.
Role in long term memory
Long term memory is referred to the memory that last for days and even decades. It is different from short term or working memory, which lasts only for seconds. This memory is divided into procedural /implicit memory and declarative/explicit memory. Implicit memory retains our skills such as how to ride a bicycle; explicit memory retains our memory about specific events and general knowledge.
Hippocampus is essential to long term memory, especially explicit or declarative memory. Long term memory is formed by a mechanism called long term potentiation. It is a synaptic activity that lasts for hours to days after a brief but strong stimulus. This causes prolonged stimulation of the respective areas in the brain that are responsible for storing memories.
Role in Spatial memory
We take our ability to navigate without conscious thought for granted. But if we thought about it, we may find that it is a very complex task. Hippocampus is one of the main organs in the brain responsible for it. To support that, several studies have found the size of hippocampus is larger in London taxi drivers than others.
What are the diseases that cause damage to the hippocampi?
Alzheimer’s disease is known to damage the hippocampus before it damages other parts. So initially, patients with this disorder cannot form new memories, even though they remember past things. In addition, these patients can become easily disoriented due to the loss of spatial memory.
Trauma to hippocampus results in profound difficulty in forming new memories (anterograde amnesia). In addition they may not be able to remember past events up to a certain time frame, usually months. But most of the older memories are not affected.
Summary
Hippocampus is one of the main organs in the brain responsible for the formation of new memories. In addition it also helps us to navigate.
