Hippocampus proper

Hippocampus is a major component of the brain in humans and other vertebrates. It belongs to the limbic system and plays essential roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation. The hippocampus is located in the medial temporal lobe of the brain. In Alzheimer's disease, the hippocampus is one of the first regions of the brain to suffer damage; memory problems and disorientation appear among the first symptoms. The structure's name comes from its resemblance to a seahorse, from the Greek hippos meaning "horse" and kampos meaning "sea monster".

Structure

The hippocampus is a complex brain structure embedded deep into the temporal lobe. It has a distinctive, curved shape somewhat resembling a seahorse when viewed in cross-section. It is divided anatomically into two major parts: the Dentate gyrus and the Ammon's horn. The hippocampus is further subdivided into the CA1, CA2, CA3, and CA4 regions. It is connected to other parts of the brain including the entorhinal cortex, which is the main input and output source of the hippocampus.

Function

The primary function of the hippocampus is the consolidation of new memories, the process by which short-term memories are converted into long-term memories. It also plays a role in spatial navigation and the processing of emotional responses. The hippocampus is particularly involved in memories associated with places and objects. It has been studied extensively in the context of learning and memory, partly because its unique structure and function make it susceptible to damage that can lead to specific patterns of memory loss.

Clinical Significance

Damage to the hippocampus can result from various causes including hypoxia, encephalitis, and traumatic brain injury. Conditions such as Alzheimer's disease and epilepsy are known to affect the hippocampus, leading to difficulties in forming new memories and navigating environments. Because of its role in memory, the hippocampus has been the focus of much research into neurodegenerative diseases.

Research

Research on the hippocampus has been pivotal in the field of neuroscience, particularly in understanding how memories are formed and stored. Studies involving both humans and animals have contributed to this understanding. The hippocampus is also a focus in the study of certain psychological conditions and their treatment, including depression and post-traumatic stress disorder (PTSD), where hippocampal volume reductions have been observed.

See Also

• Memory
• Neurogenesis
• Neurodegenerative diseases
• Spatial memory
• Temporal lobe