summ Amnesia by mikesanye


                                                            • Will have Optional experiment report at the end

                November 5, 2007

      Overview of Today’s Material                                             Amnesia
• Amnesia

• Anatomy of the MTL                                        • Pop culture—soap operas, movies, TV series

• Retrograde/anterograde                                    • First strong basis to connect cognitive memory
                                                              performance to the brain.
• What type of information is impaired?
                                                            • Memory is central to who we are.

 Depictions of amnesia in pop culture                          The greatest amnesia movie ever

• Range from ridiculous (50 First Dates) . . .

• . . . to science fiction (The Forgotten, Eternal
  Sunshine of the Spotless Mind). . .

• . . . to relatively accurate (Memento).

    Amnesia movie list (courtesy Mr                              Things that can cause amnesia

                                                          • Epilepsy surgery
                                                          • Epilepsy

                                                            • Korsakoff’s syndrome

                                                            • Alzheimer’s disease

                                                            • Closed head injury

                                                            • Stroke
• Anoxic episodes                                                        Patient HM
• Encephalitis (herpes encephalitis in particular)

                                                     • Severe epilepsy

                                                     • Bilateral temporal lobectomy in 1953 (age 27)

                                                     • Can’t learn new things

                                                     • Can remember some things from remote past
                                                       (prior to age 16)

                                                     • Can remember skills and facts.

   How amnesic is he? Stories about                      What’s ok with HM’s cognition

                                                     • Normal perception
• Howard Eichenbaum driving H.M. around.
                                                     • Normal speech, language perception

                                                     • Above average intelligence

              Types of amnesia                               Intact immediate memory

• Anterograde (can’t learn new stuff)                 • Close-to-normal memory span.

• Retrograde (can’t remember old stuff)               • Able to carry on normal conversation.

     HM has profound anterograde                     HM has temporally-graded retrograde
              amnesia                                            amnesia

• Performs very poorly on laboratory memory tasks    • Remembers things from a long time before his
• Has no recollection of anything after 1953
                                                     • Does not remember things from a short time
• Does not know words that entered the lexicon         before his injury
  after injury.
                                                     • Considerable controversy about what this means.
           Things HM Can Learn                                Mirror reading

• Mirror reading

• Pattern Tracing

• Priming (visual and verbal)

• Tower of Hanoi

• Artificial grammars

• Familiarity

                    Familiarity                  Things HM Can Learn: Procedural

• Recognizes own face in mirror
                                               • Memory can be long-lasting memory
• Less apprehensive about “meeting” familiar
  people                                       • Come from multiple modalities

                                               • Can involve complex cognitive function

                                               • Must involve some kind of association

                    The brain                               The hippocampus

           The entorhinal cortex                   What’s wrong with HM’s brain

                                                  • Hippocampus missing

                                                  • Surrounding      cortex
                                                    (including EC) gone

                                                  • Amygdala gone
    Controversy about consolidation                    Evidence from animal studies

• The standard view                              • Hard to find good tasks—Object recognition.

• Problems with the standard view                • Effects can be subtle: Bunsey & Eichenbaum
                                                   1996, Fortin et al 2004.
• Nadel & Moscovitch’s multiple-trace theory
                                                 • Interaction of delay and lesion.

 ROCs and the hippocampus (Fortin,                           Fortin et al methods
   Wright and Eichenbaum, 2004)

                                                 • Stimuli are scented cups of sand.
• How do you get a rat to do item recognition?
                                                 • Rats learn to dig in new odors—get a little fruit
• What are the stimuli?                            loop.

• How do they say “yes” or “no”                  • Say “no” by digging, say “yes” by not digging.

                                                 • Change criterion by       manipulating   payoffs,
                                                   difficulty of digging.

                 Spiffy video                              Hippocampus and ROCs


• Read amnesia chapter

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