HM MILNER

WILLIAM SCOVILLE performed experimental surgery: removed tissue from medial temporal lobe (inc. hippocampus) on both side of HM’s brain

• After op. HM remembered childhood well & personality was unchanged

• HM suffered from anterograde amnesia

  • No longer able to transfer info from STM to LTM

AIM: To study the role of the hippocampus on memory formation in a longitudinal case study

PROCEDURE:

• Example of method triangulation

  • Psychometric testing: 12 tests were given, and results were above average

  • Direct observation of behaviour

  • Interviews w/ HM & family members

  • Cognitive testing: memory recall & learning tasks (s.a. reverse mirror drawing)

  • MRI to determine extent of damage done (CORKIN 1997)

FINDINGS:

• HM could not acquire new episodic knowledge (memory of events) or new semantic knowledge (general knowledge about the world)

  • Suggests brain structures removed important for LTM (explicit memory)

• Was able to form a cognitive map of the spatial layout of his home

• Had capacity for working memory, as he could hold a normal conversation

• Procedural memories well maintained

  • Showed improvements on performance of new skills (s.a. Rev. mirror drawing)

• According to MRI scan from 1997 & 2002 (CORKIN) the temporal lobe (inc. hippocampus) had most damage: explains problem of transferral of STM to LTM

• → Researchers conclude Hippocampus plays critical role in converting memory from STM to LTM

  • Not site of storage of STM or LTM, but plays role in organisation & storage of permanent memory elsewhere in brain