The hippocampus helps to form memories and facilitate learning. Additionally, the hippocampus is part of the limbic system, and is heavily involved in producing emotions. If someone suffers damage to their hippocampus, it can cause them emotional or memory-related problems. Occasionally, people may lose their entire memory, resulting in a condition called amnesia.
The hippocampus is a paired structure of the brain, and each hemisphere of the brain contains one side of the hippocampus. If one side of the hippocampus sustains damage or injury, the brain will still form and store memories. However, if both parts of the hippocampus become damaged, new memories cannot be formed.
Because of its role in memory, the hippocampus produces an abundance of nerves over time. The hippocampus does this by using neural stem cells. The hippocampus is one of the few brain components that contains such stem cells.
Stress influences the performance of the hippocampus. When experiencing high levels of stress, the blood flow patterns in and around the hippocampus often change. The hippocampus changes with age. By the time most humans are 80, they may have lost up to 20 percent of the nerve connections within the structure, which typically impairs their memory.