Final answer:
Henry Molaison, or HM, sustained anterograde amnesia after a bilateral lobectomy to control epilepsy, which impeded his ability to form new episodic memories but left his personality, IQ, and language functions largely unaffected.
Step-by-step explanation:
After undergoing a bilateral lobectomy to control severe epilepsy, Henry Molaison, known as patient HM, experienced profound memory deficits. The removal of his hippocampus and amygdala led to anterograde amnesia, meaning he could no longer form new memories, specifically episodic memory. HM's case provided valuable insight into brain functions related to memory, showing that while his procedural memory was intact, his ability to retain new experiences or factual information was impaired.
Despite the surgery's impact, HM's personality, general intelligence, and language skills remained relatively intact. His IQ and language functions did not suffer dramatically, emphasizing the specificity of the hippocampus and medial temporal lobes in memory formation. The case of HM highlighted the cerebellum and prefrontal cortex's lack of involvement in the type of memory that HM lost, putting a spotlight on the role of the medial temporal lobe in declarative memory and learning.