Final answer:
The hippocampus is the key brain structure for the formation and consolidation of long-term memories. Damaging both the right and left hippocampi can lead to the inability to recall past memories or form new long-term memories, as exemplified by patient H.M.'s case.
Step-by-step explanation:
The hippocampus is the main switch station for memory; if the right and left areas are damaged, the past is lost.
Hippocampus plays a crucial role in forming long-term memories and in the consolidation of information from short-term to long-term memory. The long-term storage of episodic memories relies on the hippocampus as well as related structures in the medial temporal lobe, and these memories are typically located in the area of the brain where the initial sensory perception was processed.
In contrast, short-term memory, also referred to as working or active memory, is centralized in the prefrontal lobe. However, the hippocampus is not responsible for all types of memory; for instance, procedural memory and certain aspects of learning are associated with the cerebellum. Interesting insight into memory functions came from the case of patient H.M., who, after surgical removal of the medial temporal lobe regions including the hippocampus, could no longer form new long-term declarative memories, although his ability to form short-term memories remained intact, suggesting that these areas are not involved in forming new short-term memories.