This lecture explores the critical role of the hippocampus in memory formation, focusing on declarative memory and spatial representation. It discusses patient H.M.'s case, memory consolidation hypothesis, and complementary memory systems. The two-component model of declarative memory by Káli and Dayan is presented, emphasizing the interaction between neocortex and hippocampus. The hippocampus is also discussed as a long-term memory store, highlighting its associative memory function and auto-associative networks. The lecture delves into the mechanisms of memory consolidation, pattern completion, and pattern separation in the hippocampus.