HM

    Much work has been done with amnesic patients. One patient that has been involved in many studies is a patient known as HM. Surgery was done on HM in 1953 in an attempt to stop his seizures. The surgery involved removal of his medial temporal lobe. As a result of the surgery, HM incurred anterograde amnesia. He had some memory from before the surgery and very limited memory after. His short term memory (STM) was normal but he was unable to learn new material. Corkin (1968) showed that HM could learn simple tasks such as mirror tracing, rotary pursuit, and a tracking task, although he did not remember actually performing these tasks. This showed that HM had intact procedural memory even though he had no declarative memory of ever doing the task. Cohen and Corkin (1981) were able to show that HM was able to learn to do the Tower of  Hanoi again proving that he could learn procedural tasks.

Figure 1: Mirror Tracing                            Figure 2: Standard Rotary Pursuit                   Figure 3: Version of Tower of Hanoi