Final answer:
The hippocampus is the part of the brain responsible for forming new memories. It is crucial for encoding declarative memories and memory consolidation, while the cerebellum processes procedural memories and the amygdala handles emotional memories.
Step-by-step explanation:
The part of the brain responsible for laying down new memories is the hippocampus. This brain structure, located deep within the temporal lobe, is pivotal for the encoding and processing of declarative memories, such as facts and events, and is involved in memory consolidation—the process of transferring new learning into long-term memory. While the cerebellum is also important for memory, it chiefly handles procedural memories involved with tasks like playing an instrument or riding a bike.
Patients with damage to the hippocampus, such as the famous case of patient H.M., demonstrate severe impairments in forming new explicit (declarative) memories, although they may still be able to form new implicit (procedural) memories—pointing to the differentiated roles of the hippocampus and cerebellum. The amygdala also plays a role in memory, particularly emotional memories, which it helps to encode more deeply into long-term memory due to emotional arousal.