Hipokampas

The hippocampus is a small, curved structure located deep within the medial temporal lobe of the brain in humans and other vertebrates. It plays a crucial role in the formation of new memories and is also involved in learning, emotion, and navigation. The name "hippocampus" derives from the Greek words *hippos* (horse) and *kampē* (sea monster), referencing its resemblance to a seahorse when viewed in cross-section.

Anatomically, the hippocampus is composed of two main regions: the dentate gyrus and the cornu ammonis (CA), which includes subfields CA1 through CA4. It is part of the limbic system, a network of brain structures associated with emotions, memory, and motivation. The hippocampus is highly plastic, meaning its structure and function can adapt in response to experience, a property essential for memory formation.

Memory formation involves multiple stages, including encoding, consolidation, and retrieval. The hippocampus is particularly important during the encoding and consolidation phases, where it temporarily stores information before transferring it to other brain regions for long-term storage. Damage to the hippocampus, such as that observed in Alzheimer’s disease or following hippocampal lesions, can severely impair memory, particularly episodic memory—the ability to recall specific events and experiences.

Beyond memory, the hippocampus is involved in spatial navigation and the formation of cognitive maps, a function studied extensively in rodents and humans. Neuroimaging studies have shown that the hippocampus activates when individuals navigate familiar environments or recall spatial layouts. Additionally, it contributes to emotional regulation by interacting with the amygdala, another limbic structure linked to fear and stress responses.

The hippocampus is also sensitive to stress and environmental factors. Chronic stress, for example, can shrink hippocampal volume and impair memory, while enriched environments and physical exercise have been shown to promote hippocampal neurogenesis—the generation of new neurons. These findings highlight the hippocampus’s vulnerability and adaptability in response to internal and external influences.