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How does the hippocampus help form long-term memories?

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Patient H.M. and short-term memory loss explained — hippocampus Learn about Henry Molaison (better known as “patient H.M.”), whose short-term memory loss following a lobotomy helped researchers to understand how brain structures are related to brain function.

The hippocampus is essential for the formation of long-term memory, particularly regarding facts and events, known as declarative memory. While the exact mechanisms remain a subject of scientific debate, the hippocampus is widely considered to function as a critical hub for processing and consolidating new information.12

Current theories suggest several ways the hippocampus supports this process:

Binding and Indexing: The hippocampus may bind various elements of an experience—such as items and contexts—into a unified memory. Some theories propose it acts as an "index," linking distributed information stored throughout the cortex rather than storing the experience itself.1
Consolidation: The hippocampus provides temporary storage for new memories. Through interactions with the temporal lobe and cortical regions, it facilitates the gradual "uploading" of information into long-term storage within the cortex, a process that strengthens memories by relating new information to existing knowledge.2
Reducing Interference: It may support rapid learning by helping the brain distinguish between similar memories, such as events occurring on different days.1
Conscious Recollection: It is thought to be involved in the experience of mental time travel during the recall of episodic memories.1