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
1926-2008
Henry Gustav Molaison
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.
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
Mirror Writing
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) !
Everyone experiences memory loss with aging
Decline in temporal lobe size with age
Everyone experiences memory loss with aging
• What can you do?
– Minimize stress
– Proper nutrition (eat your veggies)
– Healthy lifestyle (exercise and sleep)
– Keep using your brain
– Protect your brain from injury
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
Long-term Memory
• What do you think the brain of someone that has this
“super memory” would look like?
Long-term Memory
• What if I told you it looked like this?
Kim Peek
Long-term Memory
• Kim Peek was the
inspiration for the
character Raymond
Babbit in Rain Man
• The real Kim Peek
probably wasn’t autistic
but he did have severe
developemental and
social deficits
Long-term Memory
• The moral of the story of Kim Peek is
that there is still much to learn regarding
the psychology and neuroscience of
long-term memory
Next Time
Awareness and Your Brain