Identify the structure described as a gray matter collection located under the temporal lobe and shaped like a seahorse.

• A. Almond-shaped mass of grey matter located in the temporal lobe
• B. A brain region involved in balance
• C. Gray matter collection located under the temporal lobe and shaped like a seahorse
• D. A white matter tract within the occipital lobe

Answer: (C)

The seahorse-shaped gray matter structure under the temporal lobe is the hippocampus. It sits in the medial temporal lobe as part of the limbic system, curling along the floor of the lateral ventricle. The hippocampal formation—comprising the hippocampus proper, dentate gyrus, and subiculum—is made of gray matter and has that distinctive curved shape seen in coronal views. This region is essential for forming new memories and for spatial navigation, helping convert short-term memories into long-term ones. The almond-shaped mass in the temporal lobe is the amygdala, more involved with emotions, not seahorse-shaped. A brain area tied to balance points to the cerebellum or vestibular systems, and a white matter tract in the occipital lobe wouldn’t be gray matter in this location. So the described structure is the hippocampus.