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What is anterograde amnesia and how is it connected to hippocampal damage?

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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.

Anterograde amnesia is a form of amnesia characterized by the inability to form new memories for facts and events following a precipitating trauma, disease, or injury. While individuals with this condition may retain memories from before the onset of the injury, they struggle to record or consolidate information about experiences occurring from the time of the event to the present.123

The connection between this condition and the hippocampus is rooted in the brain's memory-processing architecture. The hippocampus is a region of the limbic system primarily associated with the storage of long-term, declarative memories. When the hippocampus sustains damage—whether through surgical removal, Alzheimer disease, hypoxia, or epilepsy—the brain's ability to create new, lasting memories is severely impaired.24

A landmark example of this relationship is the case of "patient H.M.," who developed profound anterograde amnesia after the surgical removal of his hippocampus and surrounding medial temporal lobe structures to treat seizures. Consequently, hippocampal dysfunction is widely recognized as a primary driver of the memory deficits observed in anterograde amnesia.24