The hippocampus is a horse-shoe shaped area of the brain that plays an important role in consolidating information from short-term memory into long-term memory. It is part of the limbic system, a system associated with emotions and long-term memories. The hippocampus is involved in such complex processes as forming, organizing, and storing memories.
Because both sides of the brain are symmetrical, the hippocampus can be found in both hemispheres. If one side of the hippocampus is damaged or destroyed, memory function will remain nearly normal as long as the other side is undamaged.
Damage to both sides of the hippocampus can impede the ability to form new memories, known as anterograde amnesia.
Functioning of the hippocampus can also decline with age. By the time people reach their 80s, they may have lost as much as 20 percent of the nerve connections in the hippocampus. While not all older adults exhibit this neuron loss, those who do show decreased performance on memory tests.