People With Hippocampus Damage

People With Hippocampus Damage

1. Anterograde and Reterograde Amnesia

   • Anterograde - inability to form memories for events that happened after brain damage
   • Retrograde - loss of memory for events that occurred before th brain damage
     • Confined to 1-3yrs before surgery/more extensive
     • More severe for time leading up to damage
   • Amnesic patients can usually tell where they lived as a child and teenage but not able to say 3 years ago
     • Bayley, Hopkins and Squire (2006)

2. Intact Working Memory

   • STM remained in tact
   • Asked to remember 584
     • 15 min delay with no distractions, was able to repeat back
     • After distraction shifted, he forgot numbers
     • Milner (1959)
   • Other patients with severe amnesia also show normal WM, given lack of distraction
     • Shrager, Levy, Hopkins & Squire (2008)

3. Impaired Storage of LTM

   • When asked age and year, HM said 27 and year 1953
     • After few years, started guessing wildly
       • Corkin (1984)
   • Read same magazine repeatedly without getting bored
   • Told someone of childhood incident and later forgot he had told them and said the story again
     • Eichenbaum (2002)
   • Watched news every night but could only recall few events since 1953
   • Didn't recognise photo's of himself but recognised person in the mirror
     • Corkin (2002)
   • Formed weak semantic memories for new info he encountered repeatedly
     • Celebs names after 1953
   • No amnesic patients could remember the labels for each of the shapes and eventually was able to describe them.

4. Better Implicit than Explicit Memory

   • All amnesiacs show better impact than explicit memories
   • Explicit
     • Deliberate recall of information that one recognised as a memory
       • Also known as declarative
   • Implicit
     • influence of experience on behaviour even if you do not recognise that influence
     • Three hospital workers agreed to act in special ways toward patient with amnesia
       • One pleasant, one neutral, one stern
       • Asked repeatedly who they would turn to for help, mostly always picked friendly one
         • Even though they don't remember them and couldn't say why
       • Tranel & Damasio (1993)

5. Severe Impairment of Episodic Memory

   • HM Severe impairment of episodic memories
     • memories of single personal events
     • Couldn't describe any experiences after surgery
       • Retrograde amnesia was also greatest for episodic memories
   • KC damaged hippo and lost ability to create episodic memories
     • Looks at family photos, can say who is who but not the event where photo was taken
   • If you try to imagine future event you call upon memory of similar experiences and modify them
     • Studies with fMRI show describing past events and imagining future events activate same areas inc. hippo
       • Addis, Wong & Schacter (2007)

6. Intact Procedural Memory

   • Development of motor skills and habits, is a special kind of implicit memory
     • You might not be able to describe motor skill or habit in words or even recognise it as a memory
   • Learned to read words backwards but forgot he could do so
     • Corkin (2002)
   • Tetris, improve slowly though don't remember playing it