Final answer:
After H. M.'s brain surgery, he retained the ability to form procedural memories but lost the capacity to create new explicit memories due to having part of his medial temporal lobes removed, resulting in anterograde amnesia.
Step-by-step explanation:
In the famous case of H. M., after having part of his brain removed, he could still form procedural memories, read the same magazine over and over and not realize that he was reading it over and over, and he could no longer form new explicit memories.
Henry Molaison, known as H.M., underwent a bilateral lobectomy to alleviate seizures, which removed parts of his medial temporal lobes, notably the hippocampus and amygdala.
This resulted in anterograde amnesia, where he could remember most events from before his surgery but not form new episodic or semantic memories. Despite this, H.M. retained the ability to form procedural memories, which are stored differently in the brain.