The hippocampus is a grey matter structure located bilaterally in the medial temporal lobes beneath the cortex. The hippocampus can be divided into four regions, termed CA1-CA4, based on the organization of neurons within those sections. The hippocampus contributes to memory consolidation, or transferring information from short-term to long-term memory. This role is illustrated prominently in individuals with damage to the hippocampus who are unable to form new memories, a phenomenon known as anterograde amnesia. The hippocampus appears to be involved in declarative memory, namely episodic memory (memory for experiences in our lives) and memory for factual knowledge, but is unrelated to implicit memory.