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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
Causes of Amnesia• 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
RetrogradeAmnesia
AnterogradeAmnesia
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.
1926-2008Henry Gustav Molaison
• 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.
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) !
Decline in temporal lobe size with age
Everyone experiences memory loss with aging
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
• 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?
Long-term Memory
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
