Hippocampus

About the Hippocampus

The hippocampus is a curved structure in the medial temporal lobe of each hemisphere whose name comes from the Greek word for seahorse, which its shape resembles. It is part of the limbic system and is essential for forming new declarative memories, the memories of facts and events, and for consolidating them into long term storage elsewhere in the cortex. The famous case of the patient Henry Molaison, known as H.M., who lost the ability to form new memories after both hippocampi were surgically removed in 1953 to treat epilepsy, established its role in memory. The hippocampus also contains place cells that fire at specific locations, a discovery recognized by the 2014 Nobel Prize awarded to John O Keefe, May Britt Moser, and Edvard Moser. It is one of the first regions affected in Alzheimer disease, it is a frequent source of seizures in temporal lobe epilepsy, and it is one of the few areas where new neurons may form in adults.