hipokampus

Hipokampus, often called the hippocampus in English, is a seahorse-shaped brain structure located in the medial temporal lobe and part of the limbic system. Each hemisphere contains a hippocampus. The structure includes subfields such as the cornu Ammonis (CA1-CA4), the dentate gyrus, and the subiculum, collectively forming the hippocampus proper. It receives major input from the entorhinal cortex via the perforant pathway and sends outputs back to cortical areas through the subiculum and fornix.

Functions of the hipokampus include the consolidation of information from short-term memory to long-term memory, particularly for declarative or explicit memories. It also supports spatial memory and navigation, contributing to the formation of cognitive maps. At the cellular level, hippocampal neurons exhibit place cell activity, and the network participates in pattern separation (distinguishing similar memories) and pattern completion (retrieving full memories from partial cues).

Neuroplasticity and development: The dentate gyrus is one of the brain regions where adult neurogenesis occurs. Long-term potentiation and other forms of synaptic plasticity within the hippocampal circuits are considered key mechanisms underlying learning.

Clinical relevance: Bilateral damage to the hipokampus can cause severe anterograde amnesia, impairing the ability to form new explicit memories and affecting some retrograde memories. The hipokampus is also among the early affected regions in Alzheimer's disease, contributing to initial memory disturbances.