Memory IV Memory Systems Amnesia

1. Memory IVMemory SystemsAmnesia

2. Are there multiple LTM memory systems? • How do you learn a new skill? • How do you learn a new fact? • How about learning about an event? • Is there one long-term memory (LTM) system for these types of knowledge or are there multiple LTM systems?

3. A Taxonomy of Memory Systems LONG TERM MEMORY EXPLICIT (declarative) IMPLICIT (non-declarative) SEMANTIC (facts) EPISODIC (events) PRIMING (perceptual, conceptual) PROCEDURAL (skills & habits) ASSOCIATIVE LEARNING (classical & operant conditioning) Medial Temporal Lobe Cortex Striatum Amydala/ Cerebellum

4. Semantic and Episodic Memory • Semantic memory • memory for facts about the world • can a canary sing? • who is Secretary of State of the US? • Episodic memory • memory for events in our lives (temporal organization) • what did you eat for breakfast? • where were you for the Super Bowl game?

5. Semantic or Episodic Memory? • I remember that • I got soaked in the rain yesterday walking to class • Barack Obama is the President of the US • my first grade teacher could not pronounce my name the first day of school • California is facing severe drought conditions

6. Implicit and explicit memory • Implicit memory: past experiences influence perceptions, thoughts & actions without awareness that any information from past is accessed • Explicit memory: conscious access to info from the past (“I remember that..” ) -> involves conscious recollection

7. Explicit & Implicit Memory Tests Look at the following words. I will test your memory for these words in various ways.

9. Memory Test • Explicit test of memory: recall • Write down the words you remember from the list in the earlier slide • Implicit tests of memory • On the next slide, you will see some words missing letters, some “word fragments” and some anagrams. Guess what each word might be.

11. Implicit Memory Tasks • Word-fragment completion is an implicit memory task.Fragments are (often) completed with words previously studied in the absence of an explicit instruction to remember the word • Amnesiacs often show spared implicit memory dissociation suggest different systems for implicit and explicit memory systems

12. Implicit vs. Explicit Memory • Graf, Squire, & Mandler (1984): • Study words: cheese, house, … • Explicit memory test: cued recall. Complete fragment to a word from study list: ch _ _ _ _ • Implicit memory test: word stem completion. Complete fragment to form any word: ch _ _ _ _

13. Word-stem completion spared in amnesiacs Graf et al. (1984).

14. Implicit Memory • Other forms • Procedural Memory • Perceptual learning • Classical conditioning • Real-world applications • Unintentional plagiarism

15. Amnesia

16. Sources • Blow to head, Concussion • Korsakoff syndrome (severe vit. B1 deficiency) • Alzheimer’s • Damage to hippocampus, thalamic structures • ECT (electroconvulsive shock therapy) • Midazolam: artifically induced amnesia

17. Amnesia • Types: • Retrograde: cannot remember old memories • Anterograde: cannot form new episodic memories

18. Retrograde amnesia • Temporal gradient: • early memories are better remembered than memories before trauma (Ribot’s law) • Recently formed memories continue to undergo neurological change: memory consolidation

19. Temporal Gradient • Testing memory for diary entries from retrograde amnesiac (Butters & Cermak, 1986)

20. Anterograde Amnesia • Inability to acquire new information • Think of movie “memento” • Does not affect short-term memory • Does not affect general knowledge from the past • But, it is difficult to learn new facts • Affects memory regardless of modality (visual, auditory, tactile, etc). • Spares skilled performance

21. Famous Anterograde Amnesiac: HM • Surgery when 27 years old (1953) to deal with severe epilepsy • Removed bilaterally medial temporal lobes, including hippocampus • A NPR segment on HM Henry Gustav Molaison

23. H.M. • Could still retrieve memories acquired long before surgery • had normal vocabulary • average IQ • intact working memory • Profound anterograde amnesia: could not form new explicit/declarative memories • General knowledge intact but “stuck in time”: • Did not learn words introduced after 1953: “Jacuzzi”, “granola”, “flower-child”

24. HM able to form some new memories: mirror trace task Milner, 1965

25. Learning a new skill: mirror-reverse reading

26. Amnesics can learn to mirror-reverse read and are sensitive to repetitions

27. Clive Wearing • Accomplished British musician • Suffered from encephalitis • hippocampus destroyed in both hemispheres • frontal lobe damage as well • Retrograde as well as anterograde amnesia • memory lasts between 7-30 seconds

28. Clive Wearing • Diary entries: 8:31 AM: Now I am really, completely awake9:06 AM: Now I am perfectly, overwhelmingly awake9:34 AM: Now I am superlatively, actually awake

29. Clive Wearing: Video (~4min.) For full video segment see: http://www.youtube.com/watch?v=wDNDRDJy-vo&feature=&p=1DA172C40AC3B362&index=0&playnext=1

30. Clive Wearing • Spared implicit memory • emotional memory: gradual acceptance of his condition • procedural memory: layout of his residence

31. Claparède study (1911) • Claparède was a Swiss physician treating an amnesic woman • Patient never remembered having met Claparede (doctor) before • Claparade offers handshakes with pinprick • Next time, no explicit memory of event • Still, patient refuses to shake hands and offers explanation: “sometimes pins are hidden in people’s hands”

32. Amnesiacs and Trivia Questions • Korsakoff patients were given feedback, then retested. • No conscious memory for items but better performance. • Their explanation: “I read about it somewhere” (Schacter, Tulving & Wang, 1981).

33. Can amnesics acquire any new knowledge? Declarative memory (memory for information/knowledge, e.g. episodic & semantic memory)  impaired Procedural memory (e.g., how to ride a bike)  yes Implicit memories (using past information possibly without being aware of it)  yes

34. Implications • Hippocampus and surrounding structures in medial temporal love are responsible for transferring explicit memories from working memory to LTM • Separate memory systems: • working memory vs. LTM • explicit vs. implicit memory

35. Memory & The Brain • Prefrontal cortex: Short term storage of explicit memories • Hippocampus: Transfers explicit memories from working memory to LTM • Cerebellum: Implicit memories of skills, habits, conditioning