Introduction
- The study of neural circuitry underlying declarative memories began in the 1950s.
- This field was significantly influenced by the case of a single patient, HM.
The Case of HM
- Patient: Henry Molaison, referred to as HM.
- Condition: Suffered from severe, incapacitating seizures throughout childhood, adolescence, and early adulthood.
- Treatment: Underwent surgery to remove the part of the brain causing seizures.
- Surgical Procedure: Removal of the anterior portion of the temporal lobe on both sides of the brain.
- Outcome: Developed dense amnesia, unable to form new memories after the surgery.
Impact of HM’s Case
- Collaboration: William Scoville (surgeon) and Brenda Milner (neuroscientist) collaborated to study HM.
- Landmark Finding: Bilateral hippocampal removal prevents the formation of declarative memories.
- Continued Research: Suzanne Corkin, a student of Brenda Milner, extensively studied HM’s memory functions for decades.
- Publication: Corkin wrote “Permanent Present Tense,” detailing her work with HM.
Significance of HM’s Contribution
- HM’s willingness to participate in research despite his condition was invaluable.
- His case provided profound insights into memory formation and retrieval.
- HM’s personality is described as affable, with a dry sense of humor and a generous spirit.