1 / 43

Amnesia What is it?

Amnesia What is it?. Memory . Proposed Types of Memory. 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:

telma
Download Presentation

Amnesia What is it?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. AmnesiaWhat is it?

  2. Memory

  3. Proposed Types of Memory

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

  5. 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

  6. 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

  7. Amnesia • Short-term and sensory memory are typically functional

  8. Amnesia • Amnesia patients exhibit recency effect but not primacy effect

  9. 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

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

  11. 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

  12. 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

  13. Amnesia Thalamus Hippocampus

  14. Diencephalic Amnesia • Damage to the medial thalamus and/or mammillary bodies • stroke • Korsakoff’s syndrome • Caused by thiamine deficiency as a result of chronic alcoholism

  15. Korsakoff’s Syndrome The Lost Mariner - What happened to Jimmie? What was his life like?

  16. Korsakoff’s Syndrome (The Lost Mariner) • Lesions to Medial Thalamus • Results from chronic alcoholism and consequent thiamine deficiency

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

  18. 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

  19. 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

  20. 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

  21. Medial Temporal lobe amnesia • Hippocampus is most important site of damage

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

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

  24. 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

  25. 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

  26. H. M.

  27. 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)

  28. H. M. • Some aspects of memory were spared (at least to some extent)

  29. 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

  30. 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

  31. 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) !

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

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

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

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

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

  37. 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

  38. 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

  39. 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

  40. Amnesia What pattern of result can be seen across these patient’s cases? What does it suggest about memory systems?

  41. Dissociation of Memory Systems • Memory systems are “doubly-dissociated”

  42. 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

  43. Have a good Week

More Related