Final answer:
The H.M. (Henry Molaison) case study is the key study in the Process Dissociation Framework, which highlighted the distinct roles of different memory systems in the brain.
Step-by-step explanation:
The key study in the Process Dissociation Framework is the H.M. (Henry Molaison) case study. Henry Molaison, known as H.M., underwent brain surgery in 1953 to alleviate severe seizures. The surgery involved the removal of his hippocampus and amygdala, which led to unexpected and significant changes in his memory functions. Following the surgery, H.M. lost the ability to form new explicit memories, such as remembering facts or events, but retained the capacity to learn new skills, a phenomenon he wouldn't consciously recall later. H.M.'s case has been instrumental in advancing scientific understanding of the role the hippocampus plays in memory consolidation and the distinction between explicit and implicit memory.