Hippocampus

NervousOrgansHeadLeft and right

View left in 3D View right in 3D

What it is
A curved ridge of rolled-in cortex in the floor of the temporal horn of the lateral ventricle, shaped like a seahorse (Greek hippokampos): a knobbly head in front, a body and a tail curving up behind the thalamus into the fornix.
Function
Turns new experiences into long-term memories and maps places (place cells); essential for remembering facts and events.
Size
About 4-4.5 cm long and 1 cm wide
Clinical note
One of the first areas to shrink in Alzheimer disease; removal of both hippocampi left patient H.M. unable to form new memories.

Nearby nervous structures Caudate nucleus, Globus pallidus, Lateral ventricle, Midbrain, Optic tract, Putamen, Temporal lobe, Thalamus, Trochlear nerve (CN IV), Vestibulocochlear nerve (CN VIII)