Transcript Memory_partIV

Memory IV
Memory Systems
Amnesia
Are there multiple LTM memory systems?
• How do you learn a new skill?
• How do you learn a new fact?
• How about learning about an event?
• Is there one long-term memory (LTM) system for these
types of knowledge or are there multiple LTM systems?
A Taxonomy of Memory Systems
LONG TERM MEMORY
EXPLICIT
(declarative)
SEMANTIC
(facts)
EPISODIC
(events)
Medial
Temporal
Lobe
IMPLICIT
(non-declarative)
PRIMING
(perceptual,
conceptual)
Cortex
PROCEDURAL
(skills & habits)
Striatum
ASSOCIATIVE
LEARNING
(classical & operant
conditioning)
Amydala/
Cerebellum
Semantic and Episodic Memory
• Semantic memory
– memory for facts about the world
• can a canary sing?
• who is Secretary of State of the US?
• Episodic memory
– memory for events in our lives (temporal organization)
• what did you eat for breakfast?
• where were you for the Super Bowl game?
Semantic or Episodic Memory?
• I remember that
– I got soaked in the rain yesterday walking to class
– the White House is in Washington, D.C.
– my first grade teacher could not pronounce my name
the first day of school
– Barack Obama is the President of the US
Implicit and explicit memory
• Implicit memory:
past experiences influence perceptions, thoughts &
actions without awareness that any information from
past is accessed
• Explicit memory:
conscious access to info from the past
(“I remember that..” )
-> involves conscious recollection
Explicit & Implicit Memory Tests
Look at the following words. I will test your
memory for these words in various ways.
SPONGE
CANDY
DOLPHIN
PACKAGE POSTER
LICORICE
ZEBRA
SECTION
CAMOFLAGE
MISTAKE
PORTAL
KNAPSACK
COFFEE
QUAIL
ALPINE
HANDLE
PANTRY
CARPET
EAGER
CELLO
PRESSURE
LLAMA
ORIOLE
ACRID
Memory Test
• Explicit test of memory: recall
– Write down the words you remember from the list in
the earlier slide
• Implicit tests of memory
– On the next slide, you will see some words missing
letters, some “word fragments” and some anagrams.
Guess what each word might be.
EGNOPS
*AN*Y
PACKAGE P*S*E*
*OL*H**
LICORICE
*E*RA
SE*T*O*
C**O*LA*E
*I*TA*E
PORTAL
KNAPSACK
COFFEE
*U*IL
AEILNP
*AN*LE
*A*T*Y
ACEPRT
*A*E*
C*L**
*RE*S**E
AALLM
EILOOR
*C*ID
Implicit Memory Tasks
• Word-fragment completion is an implicit memory task.
Fragments are (often) completed with words previously
studied in the absence of an explicit instruction to
remember the word
• Amnesiacs often showed spared implicit memory
dissociation suggest different systems for implicit and
explicit memory systems
Implicit vs. Explicit Memory
• Graf, Squire, & Mandler (1984):
– Study words:
cheese, house, …
– Explicit memory test: cued recall.
Complete fragment to a word from study list:
ch _ _ _ _
– Implicit memory test: word stem completion. Complete
fragment to form any word:
ch _ _ _ _
Word-stem completion spared in amnesiacs
Graf et al. (1984).
Implicit Memory
• Other forms
– Procedural Memory
– Perceptual learning
– Classical conditioning
• Real-world applications
– Unintentional plagiarism
Amnesia
Sources
•
•
•
•
•
•
Blow to head, Concussion
Korsakoff syndrome (severe vit. B1 deficiency)
Alzheimer’s
Damage to hippocampus, thalamic structures
ECT (electroconvulsive shock therapy)
Midazolam: artifically induced amnesia
Amnesia
• Types:
– Retrograde: cannot remember old memories
– Anterograde: cannot form new episodic memories
Retrograde amnesia
• Temporal gradient:
– early memories are better remembered than memories
before trauma (Ribot’s law)
– Recently formed memories continue to undergo
neurological change: memory consolidation
Temporal Gradient
•
Testing memory for diary entries from retrograde amnesiac
(Butters & Cermak, 1986)
Anterograde Amnesia
• Inability to acquire new information
– Think of movie “memento”
– Does not affect short-term memory
– Does not affect general knowledge from the past
– But, it is difficult to learn new facts
– Affects memory regardless of modality (visual,
auditory, tactile, etc).
– Spares skilled performance
Famous Anterograde Amnesiac: HM
• Surgery when 27 years old (1953) to deal with severe
epilepsy
• Removed bilaterally medial temporal lobes, including
hippocampus
• A NPR segment on HM
Henry Gustav Molaison
H.M.
• Could still retrieve memories acquired long before
surgery
– had normal vocabulary
– average IQ
– intact working memory
• Profound anterograde amnesia: could not form new
explicit/declarative memories
• General knowledge intact but “stuck in time”:
– Did not learn words introduced after 1953: “Jacuzzi”,
“granola”, “flower-child”
HM able to form some new
memories: mirror trace task
Milner, 1965
Learning a new skill: mirror-reverse reading
Amnesics can learn to mirror-reverse read and are
sensitive to repetitions
Clive Wearing
• Accomplished British musician
• Suffered from encephalitis
– hippocampus destroyed in both hemispheres
– frontal lobe damage as well
• Retrograde as well as anterograde amnesia
– memory lasts between 7-30 seconds
• Diary entries:
8:31 AM: Now I am really, completely awake
9:06 AM: Now I am perfectly, overwhelmingly awake
9:34 AM: Now I am superlatively, actually awake
Clive Wearing: Video (~4min.)
For full video segment see: http://www.youtube.com/watch?v=wDNDRDJy-vo&feature=&p=1DA172C40AC3B362&index=0&playnext=1
Clive Wearing
• Spared implicit memory
– emotional memory: gradual acceptance of his
condition
– procedural memory: layout of his residence
Claparède study (1911)
• Claparède was a Swiss physician treating an amnesic
woman
•
Patient never remembered having met Claparede
(doctor) before
• Claparade offers handshakes with pinprick
• Next time, no explicit memory of event
• Still, patient refuses to shake hands and offers
explanation: “sometimes pins are hidden in people’s
hands”
Amnesiacs and Trivia Questions
• Korsakoff patients were given feedback, then retested.
• No conscious memory for items but better performance.
• Their explanation: “I read about it somewhere”
(Schacter, Tulving & Wang, 1981).
Can amnesics acquire any new knowledge?
Declarative memory (memory for information/knowledge,
e.g. episodic & semantic memory)
 impaired
Procedural memory (e.g., how to ride a bike)
 yes
Implicit memories (using past information possibly without
being aware of it)
 yes
Implications
• Hippocampus and surrounding structures in medial
temporal love are responsible for transferring explicit
memories from working memory to LTM
• Separate memory systems:
– working memory vs. LTM
– explicit vs. implicit memory
Memory & The Brain
• Prefrontal cortex: Short
term storage of explicit
memories
• Hippocampus: Transfers
explicit memories from
working memory to LTM
• Cerebellum: Implicit
memories of skills, habits,
conditioning
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