Location: The hippocampus is situated in the front part of the temporal lobe on both sides of the brain.
Structure: It’s a three-layered cerebral cortex, distinct from the six-layered neocortex.
Function: The hippocampus is crucial for the formation of both semantic (factual knowledge) and episodic (personal experiences) memories.
Without a hippocampus, new memories of both types cannot be formed.
The case of HM illustrates this point: he could not form new episodic memories (e.g., not knowing who the president is) or semantic memories (e.g., not knowing the meaning of new words).
Memory Consolidation and Retrieval
Memory Storage: Once memories are formed, they are transferred from the hippocampus to the neocortex for storage.
Semantic Memory Retrieval: Semantic memories are stored directly in the neocortex and can be accessed without involving the hippocampus.
Damage to the neocortex can result in the loss of specific semantic memories (as seen in the case of Jill Bolte Taylor, who lost her math skills).
Episodic Memory Retrieval: Episodic memories are also stored in the neocortex but require the hippocampus for retrieval (reconsolidation).
This process of reconsolidation allows for potential changes in the memory each time it is retrieved.
