Learning & Memory June 17, 2014

1. Learning & MemoryJune 17, 2014

2. Learning

3. What is Learning? Acquiring or modifying • Knowledge • Behavior • Skills Increasing understanding New perspectives, interpretation of the world

4. The Study of Learning Effect of experience on the brain Different types of learning Simple, complex Who can learn? Humans, animals, even some machines

5. Types of Learning Rote learning Avoid complexities Memorization, exact recall Meaningful learning Understanding – relate new/established knowledge

6. Types of Learning Habituation Decrease in response to repeated stimulus Sensitization Increase in response to stimuli (generally motor)

7. Types of Learning Episodic learning Response to specific event Associative learning Two stimuli, or stimuli & behavior Classical & operant conditioning

8. Conditioning Classical conditioning: neutral stimulus becomes non-neutral – paired w/ stimulus naturally producing response Pavlov’s dogs Operant conditioning: behavior reinforced or punished, alters likelihood of happening again

10. Importance of Learning Why is learning important? • Adjust, adapt behaviors • Avoid harmful situations • Assists w/ motivation, goals, choices • What something means, and means to you Intricately linked to memory • What came before? What will happen after?

11. Memory

12. Some Definitions… “Short-term”, working memory: information held briefly while attending to something Limited (digit span) Strategies – chunking, visualization/association

13. Some Definitions… Long-term memory: transferred to “storage” • Consolidation Semantic memory: general facts, events • Who is the President? What year is it? Episodic memory: personal history • First day of school

14. Some Definitions… Explicit memory: w/awareness Implicit memory: w/out awareness • Skill learning • Memories associated w/ conditioning Spatial memory: location • Navigation • Morris water maze, radial arm (animal models)

16. Case Studies in Memory

17. The Case of H.M. • Medial temporal lobes removed - seizures • 1953, 27 years old • After surgery – no new memories • Memories from childhood, things attended to • Motor learning w/ practice Changed the field of memory research – died in 2008

18. Jimmy G – The Lost Mariner • Discovered in 1975 (49 years old), “stuck” in 1945 • Believed he was 19 • Korsakoff’s syndrome – damage to medial temporal lobe, thalamus - severe alcoholism • Nutritional deficiency (thiamine) • Mammillary bodies (limbic circuit) • Confabulation

19. Jimmy G – The Lost Mariner “He is man without a past (or future), stuck in a constantly changing, meaningless moment” – Oliver Sacks

20. “You have to begin to lose your memory, if only in bits and pieces, to realize that memory is what makes our lives. Life without memory is no life at all ... Our memory is our coherence, our reason, our feeling, even our action. Without it, we are nothing…” - Luis Bunuel

21. Importance of Memory What would you lose without memory? • Connection to the world, past & future Memory gives you a “self”, a history…

22. Importance of Memory Flexible use of information – what is important to recall, and when What things to you remember? What events from your past? • How affects you (significance) • Emotional context (limbic system) • Firsthand, secondhand

23. Biology of Memory

24. Structures for Memory Hippocampus • Spatial memory • Spatial context for episodic memory Amygdala • Emotional significance • Conditioned fear

25. Structures for Memory Rhinalcortex Representations of objects for memory Mammillary bodies Recognition memory Olfactory cues Cerebellum Learned sensorimotor patterns

28. Storage & Retrieval How does experience alter neurons, and how does this produce a “memory”? How are changes in the brain coded as memories, stored, and retrieved? Many questions… not well understood

29. Long-Term Potentiation (LTP) • Cooperation/coordination of neurons - structural changes in neurocircuits, efficiency of transmission • Intense, coordinated transmission at synapse • Long-term strengthening of synapse

30. Long-Term Potentiation (LTP) • Post-synaptic firing depends on simultaneous activation • Association of several stimuli • “Coincidence detector” • Role in memory • Disruption of LTP -- disrupts memory formation/learning

31. Memory Storage No one site for “memory”, space for each “event” … • Stored diffusely, areas involved in experience – throughout cortex • Influence of sensory systems

32. Memory Retrieval • Recall not exact • Mood, stress • When “remember” – remove, use, re-consolidate • Susceptible to alteration • Not always reliable • Change reconsolidation, change the memory?

33. Disordered Memory

34. Amnesia (Memory Loss) Retrograde amnesia: things before Retrieval problem Older memories more “stable” Anterograde amnesia: things after Consolidation problem Usually for episodic memory

35. Alzheimer’s Disease Generalized memory loss • Associating context w/ memories • Spatial memory • Working (short term) memory • Implicit memory

36. Alzheimer’s Disease • Other cognitive functions • Neurophysiological changes • ACh depletion • Accumulation of beta amyloid protein (plaques) • Increased tau protein (tangles)

38. Language & Speech

39. Communication

40. Evolution of Communication Why communicate? How do we use this information? What is the benefit? How do the sensory systems aid in communication? • Visual signals, gestures • Auditory sounds, speech • Odor cues • Physical contact

41. Evolution of Communication Many species communicate • Calls, vocal signals • Ex. Honeybee dance Primates – our closest relative • Calls w/ distinct meanings • Alarm/warn kin • Gestures

42. Human Communication What is unique about human communication? • Fine motor control of voice – distinct sounds • Directed – ask questions, make comments • Relate to past/future • Combine ideas, concepts

43. Human Communication • Express limitless # of ideas • Highly verbal + use of gestures • Sign language • Hand shape, hand motion, relationship to body

44. Language Development Communication through language • Not “taught” – readily learned • Ability to express & understand words, sentences • Sensitive period – early in development • Adults have trouble learning new languages

45. Language Development • Language of parent • Distinguish sounds only for language of choice • Result in accent when speaking new language

46. Lateralization

47. Division of Labor First need to understand how the brain is lateralized (division of labor between the hemispheres) • A system of pairs (eyes, ears, limbs) - hemispheres • Slightly different roles for each – esp. for language

48. The Split Brain • Corpus callosum – connects hemispheres • Each can function independently • Most behavior relies on coordination • Split brain patients – inability to communicate between hemispheres • Transection of corpus callosum

50. Cerebral Dominance Idea that one hemisphere dominant for process • Language one of the most lateralized behaviors Be careful: avoid thinking of dominant hemisphere as most “important”, does “more” • Larger role in particular behavior