Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

A 1998 study by Dr. Peter Eriksson used the marker bromodeoxyuridine to demonstrate that neurogenesis takes place in the dentate gyrus region of this structure. The granule cells of the dentate gyrus project to the large pyramidal cells of this structures Ammons Horn via the mossy fiber system. Damage to this region may result in anterograde amnesia, and it is typically one of the first areas damaged by Alzheimers disease. A recent study found that this region has grown larger in cab drivers who have navigated London for decades, since this area is involved in spatial navigation and memory formation. For 10 points, name this part of the brain which derives its name from the Greek for seahorse.
Science