Learning and Memory: Biological Perspectives

1. Learning and Memory: Biological Perspectives

2. 17 Learning and Memory: Biological Perspectives • Many Kinds of Brain Damage Can Impair Memory • There Are Several Kinds of Memory and Learning • Memory Has Temporal Stages: Short, Intermediate, and Long • Different Regions of the Brain Process Different Aspects of Memory

3. 17 Learning and Memory: Biological Perspectives • Brain Imaging Provides Insights about Regions Involved in Different Kinds of Memories • Comparative Approaches Yield Insights about the Evolution of Learning and Memory • Learning and Memory Change throughout Life

4. 17 Many Kinds of Brain Damage Can Impair Memory Learning is the process of acquiring new information. Memory is: • The ability to store and retrieve information • The specific information stored in the brain (English tenses)

5. 17 Many Kinds of Brain Damage Can Impair Memory Patient H.M. suffers from amnesia, or memory impairment. Retrograde amnesia is the loss of memories formed before onset of amnesia. Anterograde amnesia is the inability to form memories after onset of a disorder.

6. 17 Many Kinds of Brain Damage Can Impair Memory Disease can cause memory loss by damaging the medial temporal lobe. • Herpes simplex virus • Ischemia – an episode of reduced blood supply to the brain, through stroke or heart attack

7. 17 Many Kinds of Brain Damage Can Impair Memory Damage to the hippocampus can produce memory deficits. H.M.’s surgery removed the amygdala, the hippocampus, and some cortex. H.M.’s memory deficit was confined to verbal tasks.

8. Figure 17.1 Brain Tissue Removed from Patient H.M.

9. Figure 17.2 H.M.’s Performance on a Mirror-Tracing Task (Part 1)

10. Figure 17.2 H.M.’s Performance on a Mirror-Tracing Task (Part 2)

11. 17 Many Kinds of Brain Damage Can Impair Memory Two kinds of memory: • Declarative memory – facts and information acquired through learning that can be stated or described • Nondeclarative memory, or procedural memory – shown by performance rather than recollection

12. Figure 17.3 Two Main Kinds of Memory: Declarative and Nondeclarative

13. 17 Many Kinds of Brain Damage Can Impair Memory Damage to other areas can also cause memory loss. Patient N.A. has amnesia due to accidental damage to the dorsomedial thalamus. Like H.M, he has short-term memory but cannot form declarative long-term memories.

14. Figure 17.4 The Brain Damage in Patient N.A.

15. 17 Many Kinds of Brain Damage Can Impair Memory Korsakoff’s syndrome is a memory deficiency caused by lack of thiamine – seen in chronic alcoholics. Brain damage occurs in mammillary bodies and basal frontal lobes. Confabulate – to fill in a gap in memory with a falsification

16. 17 Many Kinds of Brain Damage Can Impair Memory Two subtypes of declarative memory: • Semantic memory– generalized memory • Episodic memory– autobiographical Patient K.C., due to damage to the cortex, cannot retrieve personal (episodic) memory.

17. Figure 17.5 Subtypes of Declarative and Nondeclarative Memory

18. 17 There Are Several Kinds of Memory and Learning Types of learning: Skill learning – learning to perform a task requiring motor coordination Priming – repetition priming – a change in stimulus processing due to prior exposure to the stimulus Conditioning – the association of two stimuli, or of a stimulus and a response (S-S or S-R)

19. 17 There Are Several Kinds of Memory and Learning Nonassociative learning involves a single stimulus at t1 – three kinds: • Habituation – a decreased response to repeated presentations of a stimulus • Dishabituation – restoration of response amplitude after habituation • Sensitization – prior strong stimulation increases response to most stimuli

20. 17 There Are Several Kinds of Memory and Learning Associative learning involves relations between events. In classical conditioning – Pavlovian conditioning – a neutral stimulus is paired with another stimulus that elicits a response. Eventually the neutral stimulus by itself will elicit the response.

21. 17 There Are Several Kinds of Memory and Learning In instrumental conditioning – or operant conditioning – an association is made between: • Behavior (the instrumental response) • The consequences of the behavior (the reward)

22. 17 There Are Several Kinds of Memory and Learning Animals may learn by: • Stimulus-response chains (more chains to cognition) • Cognitive maps – mental representations of spatial relationships Latent learning is learning that takes place but is not yet demonstrated.

23. 17 Memory Has Temporal Stages: Short, Intermediate, and Long Multiple-trace hypothesis of memory classifies memory by duration: • Iconic memories are the briefest. • Short-term memories (STMs) are longer. • Anintermediate-term memory (ITM) outlasts a STM, but is not as permanent as long-term memories (LTMs), which last for days and years.

24. Figure 17.6 The Multiple-Trace Hypothesis of Memory

25. 17 Memory Has Temporal Stages: Short, Intermediate, and Long Mechanisms differ for STM and LTM storage, but are similar across species. The primacy effect is the higher performance for items at the beginning of a list (LTM). The recency effect shows better performance for the items learned most recently (STM).

26. Figure 17.7 Serial Position Curves from Immediate-Recall Experiments

27. Figure 17.8 Recognition Memory Curves for Humans, Monkeys, and Pigeons (Part 1)

28. Figure 17.8 Recognition Memory Curves for Humans, Monkeys, and Pigeons (Part 2)

29. Figure 17.8 Recognition Memory Curves for Humans, Monkeys, and Pigeons (Part 3)

30. 17 Memory Has Temporal Stages: Short, Intermediate, and Long Long-term memory has a huge capacity, but can be altered. The memory trace, or record of a learning experience, decays or fragments over time. Each time a memory trace is activated and recalled, it is subject to changes.

31. 17 Different Regions of the Brain Process Different Aspects of Memory Testing declarative memories in monkeys: • Delayed non-matching-to-sample task – must choose the object that was not seen previously Medial temporal lobe damage causes impairment on this task.

32. Figure 17.9 The Delayed Non-Matching-to-Sample Task

33. 17 Different Regions of the Brain Process Different Aspects of Memory Visual paired comparison task – measures the tendency to look at a novel object in comparison with a familiar one Patients with amnesia and monkeys with lesions of the medial temporal lobe are impaired on this task.

34. Figure 17.10 Behavioral Scores as a Function of Medial Temporal Lobe Lesions (Part 1)

35. Figure 17.10 Behavioral Scores as a Function of Medial Temporal Lobe Lesions (Part 2)

36. 17 Different Regions of the Brain Process Different Aspects of Memory Different brain regions are involved with different attributes of memories such as time or sensory perception. Working memory, or short-term memory, holds memories ready to be accessed during a task.

37. Figure 17.11 Basic Attributes of Memory and the Region of the Rat Brain That is Thought to Process Each

38. 17 Different Regions of the Brain Process Different Aspects of Memory In a spatial-location recognition task, only lesions of the hippocampus produce a deficit. A locomotor response task requires an intact caudate nucleus. Sensory perception can be measured by the object recognition task and depends on the extrastriate visual cortex.

39. Figure 17.12 Experiments to Test Specific Attributes of Animals’ Memory (Part 1)

40. Figure 17.12 Experiments to Test Specific Attributes of Animals’ Memory (Part 2)

41. Figure 17.12 Experiments to Test Specific Attributes of Animals’ Memory (Part 3)

42. 17 Different Regions of the Brain Process Different Aspects of Memory There is a (triple)dissociation among brain regions and Kesner’s tests of memory. Brain lesions in one area do not affect performance on the other tests, and performance on each test is only affected by brain lesions in one area.

43. 17 Different Regions of the Brain Process Different Aspects of Memory In rats, place cells in the hippocampus are more active as the animal moves toward a particular location. In monkeys, spatial view cells in the hippocampus respond to what the animal is looking at.

44. 17 Different Regions of the Brain Process Different Aspects of Memory Successive stages of memory: Encoding – sensory information is encoded into short-term memory Consolidation – information may be consolidated into long-term storage Retrieval – stored information is retrieved

45. Figure 17.13 Hypothesized Memory Processes: Encoding, Consolidation, and Retrieval

46. 17 Different Regions of the Brain Process Different Aspects of Memory fMRI shows brain regions involved in successful encoding of memories. For recalling pictures, the right prefrontal cortex and right parahippocampal cortex are activated. For recalling words, the same structures on the left side are activated.

47. 17 Different Regions of the Brain Process Different Aspects of Memory Consolidation of memory involves the hippocampus and takes some time to occur, as shown by lesion studies. The hippocampal system does NOT store long-term memory – that may occur in the cortex, after processing.

48. Figure 17.14 Retention by Monkeys of Object Discrimination Problems

49. 17 Different Regions of the Brain Process Different Aspects of Memory Emotions can modulate memory formation by enhancing or weakening memories according to emotional content. Beta-blockers can block the memory enhancement caused by emotional arousal.

50. 17 Different Regions of the Brain Process Different Aspects of Memory In posttraumatic stress disorder (PTSD), memories produce a stress hormone response that further reinforces the memory. Beta-blockers may help prevent formation of PTSD – other amnestic treatments may diminish the impact of traumatic memories.