A theory about one part of this structure posits that, like the cerebellum, it engages in pattern separation by expansion recoding. The perforant path provides input to this structure from the entorhinal cortex. (10[1])This structure (10[1])receives signals from the medial septum via the fornix that help regulate theta wave generation. (10[1])Molecular, granule cell, and polymorphic layers make up part (10[1])of a formation named (10[1])for this structure. Synapses between this (10[1])structure’s CA1 and (10[1])CA3 (10[1])regions (10[1])are often used (10[1])to study long-term (10[2])potentiation. (10[2]-5[1])This structure’s dentate (10[2])gyrus (-5[1])is a commonly studied site of adult neurogenesis. (10[1]-5[1])Lesions (-5[1])in the uncus, amygdala, and this structure in patient H. M. (10[4])caused (10[3])severe (10[2]-5[1])anterograde (10[1])amnesia. (10[3]-5[1])For (10[2])10 (10[1])points, (10[3])name this (10[2]-5[1])seahorse-shaped (10[10])brain (10[4])structure (10[5])important (10[2])in forming memories. (10[3])■END■ (10[4])