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Amnesia

Amnesia. Answer the following questions in your journal. . What type of memory is lost in patients who suffer from episodic amnesia? Which part of the brain is typically damaged in people who suffer from episodic amnesia? What is psychogenic amnesia? What was Karl Lashley’s hypothesis?

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Amnesia

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  1. Amnesia

  2. Answer the following questions in your journal. • What type of memory is lost in patients who suffer from episodic amnesia? • Which part of the brain is typically damaged in people who suffer from episodic amnesia? • What is psychogenic amnesia? • What was Karl Lashley’s hypothesis? • What region of the brain is responsible for explicit memory? How do we know? • Why was Karl Lashley unable to find evidence to support his hypothesis? • What region of the brain is responsible for implicit memory? How do we know?

  3. Episodic Memory Episodic memory = autobiographical memory • Personal memory of our presence and role in specific events. • It’s what allows us to create a sense of time and a personal role in the changing world What would life be like without personal memories?

  4. Episodic Amnesia • A form of amnesia associated with a loss of personal memories only • Memory for events are intact, but patients don’t recall their personal role in these events.

  5. Case study: patient K. C. • Short term memory intact • Cognitive abilities intact (can still play chess) • He knows facts about himself but has no memory for events that included him personally • Ex: he is unable to describe an event that took place in school that specifically included him but could recall going to school and the knowledge he gained there

  6. Episodic amnesia • Associated with frontal lobe injuries • May be unique to humans, due to their highly developed frontal lobes. • Not only associated with brain injury, also occurs in patients with psychiatric disorders  called psychogenic amnesia • These patients have reduced activity in the frontal lobe of their brain, which blocks the retrieval of autobiographical memories.

  7. Episodic Amnesia is associated with brain damage in the frontal regions Amnesic patient with a brain infection Patient with psychogenic amnesia Figure 14-6:

  8. Early studies of Memory • Karl Lashley’s hypothesis: • Memories are represented in the circuitry of the brain used to learn solutions to problems • If this circuitry is removed or damaged, amnesia should result. • Wasn’t able to find evidence to support his theory

  9. Case Study: Patient Henry Molaison (H. M) • In 1953, William Scoville performed a bilateral medial-temporal lobe resection on patient H.M. for relief of severe epilepsy.

  10. Patient H. M. • Brain regions removed in H. M.’s surgery: • Hippocampus • Amygdala

  11. Post surgery- Patient H. M. • Following the surgery, H.M. suffered from a severe amnesia • He could not recall any specific events that happened after the surgery (no explicit memory) • Despite this deficit, H.M. had an above average IQ, he performed well on perceptual tests, and he could still recall events from his childhood and faces • H.M.’s performance on implicit memory tests was intact

  12. What did Karl Lashley do wrong? • Most of his tests were measures of implicit memory, not explicit memory. • Had he used a test of explicit memory, he would have found a memory deficit in his rats similar to H.M.s

  13. Case Study- patient J.K. • Developed Parkinson’s disease in his mid 70s • causes damage to dopaminergic cells in the basal ganglia • Impaired ability to perform tasks that he had done all his life • Example: turning off the radio • Could still recall explicit events • Thus selective damage to the basal ganglia causes impaired implicit memory but leaves explicit memory intact.

  14. Article:Korsakoff’s Syndrome Read the article and answer the following in your journal Who? What’s the problem? Signs and symptoms. Cause. Cure?

  15. Important points 1. Who? : Joe R, 62 year old man, average intelligence, no obvious sensory or motor difficulties 2. What’s the problem?: Korsakoff’s syndrome 3. Signs and symptoms: • Severe loss of memory, both anterograde and retrograde amnesia • Make up plausible stories of past events rather than admit they don’t remember • Indifferent to suggestions that they have a memory problem • Apathetic to things going on around them

  16. Anterograde vs. Retrograde Amnesia

  17. Korsakoff’s Syndrome Normal patient Korsakoff patient

  18. 4. Cause: • Thiamine (Vitamin B1) deficiency from prolonged intake of large quantities of alcohol • Death of brain cells in the thalamus, mammillary bodies and hypothalamus • Cortical atrohpy(shriveling) in the frontal lobe 5. Cure? • Only 20% of patients show recovery after a year on a vitamin B1 –enriched diet

  19. Alzheimer’s Disease 1) Define the following words: • brain atrophy: partial or complete wasting away (shrinking) brain tissue • neuropathology: A disease of neural (brain) tissue • Afflicted: To be affected by • Postmortem: After death dementia (or demented): The loss of brain function that occurs with certain diseases. It affects memory, thinking, language, judgment, and behavior. http://www.hbo.com/alzheimers/the-films.html

  20. 2) What is the only reliable diagnostic test for Alzheimer’s disease? Postmortem examination of cerebral tissue revealing the presence of neuriticplauqes (amyloid protein) and neurofibrillary tangles 3) What 2 principal neuronal changes take place in Alzheimer’s disease? - Loss of cholinergic cells in the basal forebrain - Development of neuriticplauqes in the cerebral cortex 4) What is a treatment for Alzheimer’s disease? Cognex - cholinergic agonist: it increases levels of the neurotransmitter acetylcholine

  21. 5) What is a neuritic plaque? A bundle of cells often found in the cerebral cortex of Alzheimer’s patients. It consists of a protein (amyloid) core surrounded by bits and pieces of degenerated cells. 6) Where in the brain of Alzheimer’s patients are neuritic plaques more commonly found? In the temporal lobe areas related to memory. 7) Where in the brain of Alzheimer’s patients are neurofibrillary tangles most commonly found? In the cerebral cortex and hippocampus

  22. http://www.hbo.com/alzheimers/supplementary-understanding-and-attacking-alzheimers.htmlhttp://www.hbo.com/alzheimers/supplementary-understanding-and-attacking-alzheimers.html

  23. Thursday, May 3rd:Test on Learning and Memory Unit • Learning vs. memory • Studying Learning and Memory in the Laboratory • Different kinds of learning • Reinforcement • What Makes Explicit and Implicit Memory Different? • What Is Special about Personal Memories? • Amnesia case studies • K. C., H. M., J. K. Joe R. • Alzheimer’s Disease

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