Scientists now generally divide hippocampus function into two primary areas: memory and spatial orientation. The hippocampus allows for new episodic memories — memories about experiences or events — to be recorded and stored for retrieval at a later time. It is the part of the brain's anatomy that helps an individual find his way around without conscious thought. The hippocampus figures into the process of finding short cuts and new routes between locations. Taxi drivers have been found to have larger-than-average hippocampi.
Curled like a ram's horn beneath the medial temporal lobes, the hippocampus runs like a thick rope from one side of the brain to another. The two interlocking parts that make up this part of the brain are called the Ammon's horn and dentate gurus. The hippocampus' appearance has been compared to a seahorse. The Latin term for the creature gives the hippocampus its name.
Recent studies have reported memory deficits and reduced hippocampal volumes in posttraumatic stress disorder (PTSD).
This hippocampal function is linked to rhythms, so-called oscillations. These rhythms are very similar to the brain waves measured by a physician using an electroencephalograph. The development of these rhythms depends on organized interaction between a multitude of nerve cells. Research in recent years demonstrated that suppression -- or intensification -- of brain oscillations can impair or improve learning.
Spatial Navigation: Hippocampus is believed to have a very active role in memorizing information about spatial orientation and navigation. This theory has been proven by studies conducted on rats and some other animals. It was revealed that in rodents, a healthy hippocampus is very much required for proper navigation. This is said to be relevant for humans too. This could be the reason why people with Alzheimer's disease fail to remember new locations and routes.
Memory: Though the role of hippocampus in forming new episodic memories is still not conclusive, it is believed that this part of the brain plays a vital role in processing current information and memorizing it. It is believed that rather than storing information, hippocampus processes new information to be stored somewhere else in the cortex. This is the reason why people retain old memories even though the hippocampus gets damaged. However, they fail to memorize current events and make new memories. This happens to those with Alzheimer's disease.
Emotion and memory are very closely related. You know this from your experience. Go to a party, meet a bunch of new people. Which faces are you going to remember? The woman who made you laugh, the man who made you feel embarrassed, and your new boss -- the ones who had an emotional impact.
So perhaps you would not be surprised to learn that the a portion of the emotion system of the brain (the "limbic system") is in charge of transferring information into memory. From years of experiments and surgical experience, we now know that the main location for this transfer is a portion of the temporal lobe called the hippocampus.
The hippocampus is a part of the forebrain, located in the medial temporal lobe. It is critical for the formation of those kinds of memories, which can be consciously declared. Due to its self-generated network patterns, newly acquired memories are gradually transferred to neocortical stores through the process of memory consolidation.
In Alzheimer's disease the hippocampus is one of the first regions of the brain to suffer damage; memory problems and disorientation appear among the first symptoms. Damage to the hippocampus can also result from oxygen starvation (hypoxia), encephalitis, or medial temporal lobe epilepsy. People with extensive hippocampal damage may experience amnesia—the inability to form or retain new memories.
The hippocampus is a major component of the brains of humans and other mammals. It belongs to the limbic system and plays important roles in long-term memory and spatial navigation. Like the cerebral cortex, with which it is closely associated, it is a paired structure, with mirror-image halves in the left and right sides of the brain. In humans and other primates, the hippocampus is located inside the medial temporal lobe, beneath the cortical surface.