The hippocampus is a complex brain structure that influences our ability to learn, remember, and navigate. It plays a foundational role in how we interact with the world around us.
Where the Hippocampus is Located
The hippocampus is a paired structure, with one located in each cerebral hemisphere. It resides deep within the medial temporal lobe, an area situated towards the bottom and middle part of the brain. Its distinctive, curved shape has been likened to a seahorse, which is how it received its name from Greek words meaning “horse” and “sea monster.” This region is also a major component of the limbic system, a network of brain structures influencing emotion and memory.
Its Primary Roles
The hippocampus plays a primary role in converting information from short-term to long-term memory. It is involved in forming new explicit memories, also known as declarative memories, which are those we can consciously recall. This includes episodic memories, recollections of personal events and experiences, and semantic memories, encompassing facts and general knowledge.
The hippocampus also plays a role in spatial memory, allowing for navigation and understanding one’s environment. It helps create a “cognitive map” of surroundings, enabling individuals to remember layouts and routes. While it processes these memories, it does not serve as their long-term storage site; instead, it consolidates them before transfer to other brain regions for permanent retention.
How We See Its Work in Action
The hippocampus’s work is evident in everyday scenarios involving memory and navigation. When you recall details from a recent family vacation, such as the specific beach you visited or a funny incident during dinner, your hippocampus was instrumental in forming those episodic memories. Remembering what you had for breakfast or the sequence of events during your first day at a new job also relies on this structure.
The formation of semantic memories also demonstrates hippocampal activity. For instance, when you study for a test and learn new facts, like the capitals of different countries or scientific formulas, the hippocampus helps integrate this new knowledge into your long-term memory. Remembering someone’s name after being introduced or recalling a historical date discussed in a documentary involves this structure’s contribution to factual recall.
Spatial navigation provides another clear illustration of hippocampal function. Imagine finding your way around a large, unfamiliar building; your hippocampus helps you create a mental map of the new layout. Remembering where you parked your car in a vast parking lot, especially if it was a new location, is another example of its role in spatial memory. Navigating a familiar route to work or a friend’s house without getting lost also shows how the hippocampus helps maintain a stable sense of your environment.
When It Does Not Work Properly
Damage or dysfunction of the hippocampus can lead to cognitive impairments. One well-known consequence is anterograde amnesia, the inability to form new memories after the damage occurs. Individuals with this condition might forget new information minutes after learning it, effectively living in a constant present. While they may retain memories from before the damage, they struggle to recall recent events or acquire new facts.
Difficulties with spatial navigation are also common when the hippocampus is compromised. Someone affected might frequently get lost, even in familiar places like their own neighborhood or home. This occurs because the brain struggles to create or update the mental maps necessary for effective wayfinding.
The hippocampus is also one of the first brain regions affected in neurodegenerative diseases like Alzheimer’s disease. Early symptoms often include short-term memory loss and disorientation, reflecting initial damage to this structure. As the disease progresses, these memory and navigational challenges become more pronounced, impacting an individual’s daily life and independence.