Model of Memory
RETRIEVAL
Turning now to Long-Term Memory
ATTENTION
Sensory
Signals
Sensory
Memory
Short-Term
Memory
Long-Term
Memory
REHEARSAL
Some Distinctions in LTM
• Endel Tulving: There are two broad
categories of information that are
represented in LTM • Episodic Memory: memory of an event
in your life
• autobiographical
• has a temporal context - something about time
is encoded along with the memory
Some Distinctions in LTM
• Endel Tulving: There are two broad
categories of information that are
represented in LTM • Semantic Memory: memory of facts,
knowledge of the world
• unconnected to an autobiographical event
• no temporal context
Some Distinctions in LTM
• Procedural Memory: memory for actions
Long-Term Memory
• Capacity is huge (unlimited?)
Long-Term Memory
• Structure of encoding is associative
When You Don’t Remember
• Two reasons why you don’t remember:
When You Don’t Remember
• Two reasons why you don’t remember:
• Unavailable
– It wasn’t successfully encoded - something
went wrong while you were studying
When You Don’t Remember
• Two reasons why you don’t remember:
• Unavailable
– It wasn’t successfully encoded - something
went wrong while you were studying
• Inaccessible
– memory is stored but cannot be retrieved,
perhaps because appropriate connections
aren’t being made
Implicit vs. Explicit Memory
• Implicit Memories are ones that are
encoded and present, but are not
consciously accessible
• Explicit Memories are memories to
which you have conscious access
Amnesia
• Loss of memory ability - usually due to
lesion or surgical removal of various
parts of the brain
Causes of Amnesia
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Concussion
Migraines
Hypoglycemia
Epilepsy
Electroconvulsive shock therapy
Specific brain lesions (i.e. surgical removal)
Ischemic events
Drugs (esp. anesthetics)
Infection
Psychological
Nutritional deficiency
Lack of Sleep!
Amnesia
• Loss of memory ability - usually due to
lesion or surgical removal of various
parts of the brain
• Two broad categories:
– Retrograde: loss of memories for events
prior to damage
Amnesia
• Loss of memory ability - usually due to
lesion or surgical removal of various
parts of the brain
• Two broad categories:
– Retrograde: loss of memories for events
prior to damage
– Anterograde: loss of ability to store new
memories of events after damage
Amnesia
Retrograde
Amnesia
Anterograde
Amnesia
Amnesia
• Short-term and sensory memory are
typically functional
Korsakoff’s Syndrome
The Lost Mariner - What happened to
Jimmie? What was his life like?
Korsakoff’s Syndrome (The
Lost Mariner)
• Lesions to Medial Thalamus
– Results from chronic alcoholism and
consequent thiamine deficiency
Korsakoff’s Syndrome (The
Lost Mariner)
• Lesions to Medial Thalamus
– Results from chronic alcoholism and
consequent thiamine deficiency
– Severe anterograde amnesia
Korsakoff’s Syndrome (The
Lost Mariner)
• Lesions to Medial Thalamus
– Results from chronic alcoholism and
consequent thiamine deficiency
– Severe anterograde amnesia
– Severe retrograde amnesia extending
years before damage
Korsakoff’s Syndrome (The
Lost Mariner)
• Lesions to Medial Thalamus
– Results from chronic alcoholism and
consequent thiamine deficiency
– Severe anterograde amnesia
– Severe retrograde amnesia extending
years before damage
– Confabulation - make up stories to explain
absence of memory
Korsakoff’s Syndrome (The
Lost Mariner)
• Lesions to Medial Thalamus
– Results from chronic alcoholism and
consequent thiamine deficiency
– Severe anterograde amnesia
– Severe retrograde amnesia extending
years before damage
– Confabulation - make up stories to explain
absence of memory
– Often unaware of their deficit
H. M.
• Patient H. M. - suffered from extreme
epilepsy
H. M.
• Patient H. M. - bilateral resection of medial
temporal lobes (containing hippocampus)
– William Beecher Scoville and Brenda
Milner - late 1950’s
H. M.
• Patient H. M. - bilateral resection of medial
temporal lobes (containing hippocampus)
– William Beecher Scoville and Brenda
Milner - late 1950’s
– Severe anterograde amnesia
H. M.
• Patient H. M. - bilateral resection of medial
temporal lobes (containing hippocampus)
– William Beecher Scoville and Brenda
Milner - late 1950’s
– Severe anterograde amnesia
– Retrograde amnesia for 1 - 3 years before
surgery
H. M.
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
H. M.
• Some aspects of memory were spared
(at least to some extent)
H. M.
• Some aspects of memory were spared
(at least to some extent)
– Procedural memory was largely unaffected
- amnesia was largely restricted to episodic
memory
H. M.
• Some aspects of memory were spared
(at least to some extent)
– Procedural memory was largely unaffected
- amnesia was largely restricted to episodic
memory
– Some implicit awareness of recent events
H. M.
• Some aspects of memory were spared
(at least to some extent)
– Procedural memory was largely unaffected
- amnesia was largely restricted to episodic
memory
– Some implicit awareness of recent events
– Normal digit span (short-term memory) !
Hypermnesia - S.
• “Photographic” extreme memory ability
(a mnemonist)
Hypermnesia - S.
• “Photographic” extreme memory ability
(a mnemonist)
• Able to recall complex test stimuli
Hypermnesia - S.
• S. used two “strategies” or abilities
typical of mnemonists:
– Rich synesthesia-like quality to his
perception of stimuli - leads to stronger
associative links
Hypermnesia - S.
• S. used two “strategies” or abilities
typical of mnemonists:
– Rich synesthesia-like quality to his
perception of stimuli - leads to stronger
associative links
– Vivid and elaborate mental imagery of
things he should remember
Hypermnesia - S.
• “ Even numbers remind me of images.
Take the number 1. This is a proud,
well-built man; 2 is a high-spirited
woman; 3 a gloomy person (shy, I don’t
Know); 6 a man with a swollen foot...”
Luria, A.R. The mind of a mnemonist. 1968
Luria, A.R. The man with a shattered world. 1972
Next Time
Recall and false memories - Loftus