Amnesia What is it?

Memory

Proposed Types of Memory Fact memory Skill memory Declarative Non-declarative (Procedural) MemoryHabit ExplicitImplicit Knowing that Knowing How Cognitive mediation Semantic Conscious recollection Skills ElaborationIntegration AutobiographicalPerceptual RepresentationalDispositional Vertical association Horizontal association EpisodicSemantic

Amnesia Loss of memory ability - usually due to lesion or surgical removal of various parts of the brain Loss of memory ability - usually due to lesion or surgical removal of various parts of the brain

Amnesia Two broad categories: Two broad categories: Retrograde: loss of memories for events prior to damage 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 Loss of memory ability - usually due to lesion or surgical removal of various parts of the brain Two broad categories: Two broad categories: Retrograde: loss of memories for events prior to damage Retrograde: loss of memories for events prior to damage Anterograde: loss of ability to store new memories of events after damage Anterograde: loss of ability to store new memories of events after damage

Amnesia Short-term and sensory memory are typically functional Short-term and sensory memory are typically functional

Amnesia Amnesia patients exhibit recency effect but not primacy effect Amnesia patients exhibit recency effect but not primacy effect

Causes of Amnesia Concussion Concussion Migraines Migraines Hypoglycemia Hypoglycemia Epilepsy Epilepsy Electroconvulsive shock therapy Electroconvulsive shock therapy Specific brain lesions (i.e. surgical removal) Specific brain lesions (i.e. surgical removal) Ischemic events Ischemic events Drugs (esp. anesthetics) Drugs (esp. anesthetics) Infection Infection Psychological Psychological Nutritional deficiency Nutritional deficiency

Amnesia - associated brain regions Diencephalic amnesia - damage to the medial thalamus and mammillary nuclei Diencephalic amnesia - damage to the medial thalamus and mammillary nuclei

Amnesia - associated brain regions Diencephalic amnesia - damage to the medial thalamus and mammillary nuclei 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 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 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 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 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 Damage to the medial thalamus and/or mammillary bodies stroke stroke Korsakoff’s syndrome Korsakoff’s syndrome Caused by thiamine deficiency as a result of chronic alcoholism 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 Lesions to Medial Thalamus Results from chronic alcoholism and consequent thiamine deficiency Results from chronic alcoholism and consequent thiamine deficiency

Korsakoff’s Syndrome (The Lost Mariner) Lesions to Medial Thalamus Lesions to Medial Thalamus Results from chronic alcoholism and consequent thiamine deficiency Results from chronic alcoholism and consequent thiamine deficiency Severe anterograde amnesia Severe anterograde amnesia

Korsakoff’s Syndrome (The Lost Mariner) Lesions to Medial Thalamus Lesions to Medial Thalamus Results from chronic alcoholism and consequent thiamine deficiency Results from chronic alcoholism and consequent thiamine deficiency Severe anterograde amnesia Severe anterograde amnesia Severe retrograde amnesia extending years before damage Severe retrograde amnesia extending years before damage

Korsakoff’s Syndrome (The Lost Mariner) Lesions to Medial Thalamus Lesions to Medial Thalamus Results from chronic alcoholism and consequent thiamine deficiency Results from chronic alcoholism and consequent thiamine deficiency Severe anterograde amnesia Severe anterograde amnesia Severe retrograde amnesia extending years before damage Severe retrograde amnesia extending years before damage Confabulation - make up stories to explain absence of memory Confabulation - make up stories to explain absence of memory

Korsakoff’s Syndrome (The Lost Mariner) Lesions to Medial Thalamus Lesions to Medial Thalamus Results from chronic alcoholism and consequent thiamine deficiency Results from chronic alcoholism and consequent thiamine deficiency Severe anterograde amnesia Severe anterograde amnesia Severe retrograde amnesia extending years before damage Severe retrograde amnesia extending years before damage Confabulation - make up stories to explain absence of memory Confabulation - make up stories to explain absence of memory Often unaware of their deficit Often unaware of their deficit

Medial Temporal lobe amnesia Hippocampus is most important site of damage Hippocampus is most important site of damage

H. M. Patient H. M. - suffered from extreme epilepsy Patient H. M. - suffered from extreme epilepsy

H. M. Patient H. M. - bilateral resection of medial temporal lobes (containing hippocampus) Patient H. M. - bilateral resection of medial temporal lobes (containing hippocampus) William Beecher Scoville and Brenda Milner - late 1950’s William Beecher Scoville and Brenda Milner - late 1950’s

H. M. Patient H. M. - bilateral resection of medial temporal lobes (containing hippocampus) Patient H. M. - bilateral resection of medial temporal lobes (containing hippocampus) William Beecher Scoville and Brenda Milner - late 1950’s William Beecher Scoville and Brenda Milner - late 1950’s Severe anterograde amnesia Severe anterograde amnesia

H. M. Patient H. M. - bilateral resection of medial temporal lobes (containing hippocampus) Patient H. M. - bilateral resection of medial temporal lobes (containing hippocampus) William Beecher Scoville and Brenda Milner - late 1950’s William Beecher Scoville and Brenda Milner - late 1950’s Severe anterograde amnesia Severe anterograde amnesia Retrograde amnesia for years before surgery Retrograde amnesia for years before surgery

H. M.

Patient H. M. - bilateral resection of medial temporal lobes (containing hippocampus) Patient H. M. - bilateral resection of medial temporal lobes (containing hippocampus) William Beecher Scoville and Brenda Milner - late 1950’s William Beecher Scoville and Brenda Milner - late 1950’s Severe anterograde amnesia Severe anterograde amnesia Retrograde amnesia for years before surgery Retrograde amnesia for years before surgery Disconnection of autonomic responses such as hunger/satiety and Galvanic Skin Response (GSR) 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) Some aspects of memory were spared (at least to some extent)

H. M. Some aspects of memory were spared (at least to some extent) Some aspects of memory were spared (at least to some extent) Procedural memory was largely unaffected - amnesia was largely restricted to episodic memory 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) Some aspects of memory were spared (at least to some extent) Procedural memory was largely unaffected - amnesia was largely restricted to episodic memory Procedural memory was largely unaffected - amnesia was largely restricted to episodic memory Some implicit awareness of recent events Some implicit awareness of recent events

H. M. Some aspects of memory were spared (at least to some extent) Some aspects of memory were spared (at least to some extent) Procedural memory was largely unaffected - amnesia was largely restricted to episodic memory Procedural memory was largely unaffected - amnesia was largely restricted to episodic memory Some implicit awareness of recent events Some implicit awareness of recent events Normal digit span (short-term memory) ! Normal digit span (short-term memory) !

E. P. Suffered acute viral disease in brain Suffered acute viral disease in brain Damage sustained in temporal lobes, notably the hippocampus Damage sustained in temporal lobes, notably the hippocampus

E. P. Suffered acute viral disease in brain Suffered acute viral disease in brain Damage sustained in temporal lobes, notably the hippocampus Damage sustained in temporal lobes, notably the hippocampus Displays anterograde amnesia Displays anterograde amnesia Short term memory intact Short term memory intact Lives in a permanent present Lives in a permanent present

E. P. Suffered acute viral disease in brain Suffered acute viral disease in brain Damage sustained in temporal lobes, notably the hippocampus Damage sustained in temporal lobes, notably the hippocampus Displays anterograde amnesia Displays anterograde amnesia Short term memory intact Short term memory intact Lives in a permanent present Lives in a permanent present What else can we infer from the interview seen? What else can we infer from the interview seen?

Hypermnesia - S. “Photographic” extreme memory ability (a mnemonist) “Photographic” extreme memory ability (a mnemonist)

Hypermnesia - S. “Photographic” extreme memory ability (a mnemonist) “Photographic” extreme memory ability (a mnemonist) Able to recall complex test stimuli Able to recall complex test stimuli

Hypermnesia - S. S. used two “strategies” or abilities typical of mnemonists: S. used two “strategies” or abilities typical of mnemonists: Rich synesthesia-like quality to his perception of stimuli - leads to stronger associative links 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: S. used two “strategies” or abilities typical of mnemonists: Rich synesthesia-like quality to his perception of stimuli - leads to stronger associative links Rich synesthesia-like quality to his perception of stimuli - leads to stronger associative links Vivid and elaborate mental imagery of things he should remember 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...” “ 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 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” Memory systems are “doubly-dissociated”

Dissociation of Memory Systems Memory systems are “doubly-dissociated” 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 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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