Amnesia
What is it?
Memory
Proposed Types of Memory
Fact memory
Skill memory
Declarative
Non-declarative (Procedural)
Memory
Habit
Explicit
Implicit
Knowing that
Knowing How
Cognitive mediation
Semantic
Conscious recollection
Skills
Elaboration
Integration
Autobiographical
Perceptual
Representational
Dispositional
Vertical association
Horizontal association
Episodic
Semantic
Amnesia

Loss of memory ability - usually due to
lesion or surgical removal of various parts
of the brain
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

Short-term and sensory memory are
typically functional
Amnesia

Amnesia patients exhibit recency effect
but not primacy effect
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
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
Amnesia - associated brain
regions

Diencephalic amnesia - damage to the
medial thalamus and mammillary nuclei
Amnesia - associated brain
regions


Diencephalic amnesia - damage to the
medial thalamus and mammillary nuclei
Medial temporal lobe amnesia - damage to
the hippocampal formation, uncus,
amygdala, and surrounding cortical areas
Amnesia - associated brain
regions



Diencephalic amnesia - damage to the
medial thalamus and mammillary nuclei
Medial temporal lobe amnesia - damage to
the hippocampal formation, uncus,
amygdala, and surrounding cortical areas
Other implicated regions include Anterior
Lateral Temporal Lobe and Frontal Lobes
Amnesia
Hippocampus
Thalamus
Diencephalic Amnesia

Damage to the medial
thalamus and/or
mammillary bodies
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stroke
Korsakoff’s syndrome

Caused by thiamine
deficiency as a result
of chronic alcoholism
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

Medial Temporal lobe
amnesia

Hippocampus is most important site of
damage
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.

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
 Disconnection of autonomic responses such
as hunger/satiety and Galvanic Skin
Response (GSR)
H. M.

Some aspects of memory were spared (at
least to some extent)
H. M.
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Some aspects of memory were spared (at
least to some extent)
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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) !
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E. P.

Suffered acute viral disease in brain
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Damage sustained in temporal lobes, notably
the hippocampus
E. P.

Suffered acute viral disease in brain
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Damage sustained in temporal lobes, notably
the hippocampus
Displays anterograde amnesia
Short term memory intact
 Lives in a permanent present
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E. P.

Suffered acute viral disease in brain

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Damage sustained in temporal lobes, notably
the hippocampus
Displays anterograde amnesia
Short term memory intact
 Lives in a permanent present
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What else can we infer from the interview
seen?
Hypermnesia - S.

“Photographic” extreme memory ability (a
mnemonist)
Hypermnesia - S.

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“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
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Hypermnesia - S.

“ Even numbers remind me of images.
Take the number 1. This is a proud, wellbuilt 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
Amnesia
What pattern of result can be seen across these
patient’s cases? What does it suggest about
memory systems?
Dissociation of Memory
Systems

Memory systems are “doubly-dissociated”
Dissociation of Memory
Systems

Memory systems are “doubly-dissociated”

Patient H.M.’s lesion affected only episodic
long-term memory - semantic and procedural
memory were intact - short-term memory was
intact
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