HM: Milner (1966)

• Aim

  • To investigate the role of the hippocampus in memory formation and determine the effects of its removal on cognitive function.
• • Aim:
  • To investigate the role of the hippocampus in memory formation, specifically in the context of how it affects the transfer of short-term memory to long-term memory.
• Research Method:

  • Case Study: A detailed investigation into the unique circumstances of one individual (HM) over time. This method included both qualitative data (interviews, observations) and quantitative data (IQ tests, memory tasks).
• Procedure:

  • HM underwent surgery to treat his epileptic seizures, which involved the removal of parts of his temporal lobe, including the hippocampus.
  • Milner carried out a series of tests to understand HM's memory functioning. This included:
  • IQ testing
  • Direct observations of HM’s behavior
  • Interviews with HM and his family
  • Cognitive tests, including memory tasks and learning exercises
  • A mirror drawing task to assess procedural memory
• Results:

  • HM had severe anterograde amnesia, meaning he could not form new episodic or semantic memories after the surgery.
  • He could, however, learn and retain new procedural memories, such as the mirror drawing task, but could not remember performing the task.
  • An MRI scan later showed that the hippocampus was severely damaged in HM, which was consistent with his memory difficulties.
• Conclusion:

  • The hippocampus is crucial for transferring short-term memories to long-term memories.
  • The hippocampus is not responsible for short-term memory or procedural memories.
  • The study supports the idea that specific brain regions (like the hippocampus) are localized for particular cognitive functions, in this case, memory consolidation.