The entorhinal cortex is one of the brain's most important memory centers. Its main function is to relay messages to and from the hippocampus, which is viewed as one of the major sections of the brain and the epicenter of long-term memory and spatial navigation. The entorhinal cortex is situated in the medial temporal lobe, underneath the cerebral cortex and close to the hippocampus. It is one of the first areas of the brain to be affected by the plaque buildup of Alzheimer's disease.
Behavior, emotion, and memory are a few of the functions handled by the brain's limbic system. The entorhinal cortex is typically considered a part of this structure. The five senses relay information to the hippocampus via this cortex. It also transmits messages between the hippocampus and the neocortex, the area of the brain that handles motor skills, conscious thought, and sense perceptions, among several other vital functions.
The entorhinal cortex plays a central role in memory. This region processes and combines memories, most notably during sleep cycles. It also utilizes sensory information to deduce whether a particular sensory event has been experienced previously.
From the perspective of neuroanatomy — the tissues and structures of the nervous system — the entorhinal cortex also holds some major responsibility. It is thought that this cortex retains a neural blueprint of spatial movements. The area has a number of "path cells," which help an individual navigate clockwise or counterclockwise paths of movement.
When Alzheimer's disease strikes, it produces amyloid plaque accumulation within the brain. Amyloid is a type of fibrous protein buildup that is the biological hallmark of Alzheimer's. After plaque collects in the neocortex, it attacks the entorhinal cortex, making it one of the earliest-hit areas of the Alzheimer's-affected brain. Other proteins called neurofibrillary tangles also reach into this cortex before they reach other areas of the brain.
The accrual of these substances directly impacts the entorhinal cortex's ability to function properly. In many cases, the entire area atrophies during Alzheimer's. This process results in major problems of short-term memory preservation, memory consolidation, and spatial navigation.
Further research into the entorhinal cortex suggests that the region may also play a role in the development of depression and schizophrenia. One study demonstrated that the right side of the cortex was significantly smaller in elderly patients with clinical depression. Also, brain atrophy associated with schizophrenia might begin in this region.