Case Study - HM Flashcards
What was the name of HM main deficit?
Anterograde and retrograde amnesia
What is the definition of amnesia?
Defined as poor performance on memory tests as compared to the patients IQ
Which researchers studied him?
Scoville and Milner (1957)
What were the locations of HMs lesions?
Bilateral resection of the medial temporal lobes
Believed to be 5cm of the 8cm
Why was resecting the medial temporal lobes more dangerous than another area ?
They are deep structures in the brain
If only 5cm of the 8cm of medial temporal lobe was respected what does that suggest about the localisation of memory ?
Part of that brain area if not involved in memory, the 3cm left are not important for memory
What impairments did HM show?
Anterograde amnesia , failure to store new memories
Retrograde amnesia, failure to retrieve old memories from about 3 years before The surgery
Episodic memory
Amnosia
Which functions were spared for HM?
Short term memory Procedural memory Semantic facts about the world and himself Social interactions Full range of emotions but blunted Intelligence Language and executive planning
Which task was used to test short term memory?
Digit span which was normal
Which researcher suggested that we keep our oldest memories which normally tend to be semantic ones like our name, birthday etc which we learn in the first few years of life?
Ribot (1882)
Which tasks were used for testing?
Mirror drawing task - showed improvement even though he didn’t remember doing it before, shows procedural memory
Wechsler memory test
Digit span for STM
Which brain structure might aid procedural memory? That HM has preserved ?
The cerebellum
Knowlton, squire and Gluck (1994) devised what test used on a control, amnesic patients and Parkinson patients ?
The test has geometric shapes that predicted the likely weather pattern of the day with 60-80% accuracy. Many normal patients felt like they were guessing but show learning over 50-100 trials.
Amnesic patients show a similar pattern In implicit learning
But Parkinson patients show the opposite dissociation, getting worse as the trials progress, showing the importance of the basal ganglia for habitual learning
Conclusions about memory can be drawn from the case of HM, as well as about the temporal lobe and memory. What are they?
There are multiple memory systems hence why HM could retain some memory systems like STM but then lost others like episodic
The medial temporal lobes are crucial for the storage of episodic memories
What is the case history of Henry malaison?
Suffered a cycling accident as a child that triggered seizures
Seizures gradually became more severe over time
By 27 he couldn’t hold down a steady job or care for himself
