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Re-examining episodic amnesia with patient and fMRI studies

Re-examining episodic amnesia with patient and fMRI studies. Jenny Rabin Neuropsychology Rounds September 9, 2013. What is Amnesia?. Impaired Abilities Episodic memory (EM). Spared Abilities General intelligence Semantic m emory Procedural memory Working memory Attention. Amnesia.

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Re-examining episodic amnesia with patient and fMRI studies

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  1. Re-examining episodic amnesia with patient and fMRI studies Jenny Rabin Neuropsychology Rounds September 9, 2013

  2. What is Amnesia? Impaired Abilities • Episodic memory (EM) Spared Abilities • General intelligence • Semantic memory • Procedural memory • Working memory • Attention

  3. Amnesia

  4. Amnesia • For a long time it was thought that amnesia results in an isolated deficit in EM • However, there is growing evidence that other abilities may be impaired in amnesia • E.g., Future thinking • Early support came from conversations EndelTulving had with K.C. (Tulving, 1985) • Systematically replicated in other amnesic cases (Andelman et al., 2010; Kwan et al, 2010; Race et al., 2011)

  5. EM and Future Thinking Remembering Future Thinking • Both abilities supported by a common core network Addis et al., 2007, Neuropsychologia

  6. EM and Future Thinking Remembering Future Thinking • Both abilities supported by a common core network • EM and the hippocampus contribute to imagining the future • draw on details from past experiences to imagine future events Addis et al., 2007, Neuropsychologia

  7. Are there other abilities impaired in amnesia?

  8. Theory of Mind (ToM) • The ability to infer other people’s thoughts, feelings, beliefs, desires, and intentions (Premack & Woodruff, 1978) • Recognize that other people can have different mental states from our own • Use ToM automatically and effortlessly

  9. Theory of Mind (ToM) • How do we do infer others’ mental states? • We rely on our own past experiences to simulate another person’s mental state (Buckner & Carroll, 2007; Gallagher & Frith, 2003; Spreng & Mar, 2012)

  10. EM and ToM • There is evidence supporting the idea that ToM may rely on EM • Both abilities emerge around the same time during development (Perner & Ruffman, 1995) • Impaired together in several patient populations (Corcorran & Frith, 2003; Dimaggio et al., 2012) • Supported by a common set of brain regions that includes the hippocampus (Buckner & Carroll, 2007)

  11. EM, Future Thinking, and ToM EM Future Thinking ToM Addis et al., 2007 Saxe & Kanwisher, 2003 Buckner & Carroll, 2007

  12. EM, Future Thinking, and ToM Schacter, Addis & Buckner, 2008, Nat. Neurosci.

  13. Outline Study 1: Is ToM impaired in amnesia? Study 2: What are the unique neural correlates of EM and ToM? Study 3 and 4: Are there certain conditions under which ToM depends on EM?

  14. Outline Study 1: Is ToM impaired in amnesia? Study 2: What are the unique neural correlates of EM and ToM? Study 3 and 4: Are there certain conditions under which ToM depends on EM?

  15. Study 1 • Evidence that a core network of regions supports EM, future thinking, and ToM(Buckner & Carroll, Spreng et al., 2009) • Draw on past experiences to imagine the future and to simulate other people’s mental states • Amnesic people have difficulty imagining the future (Andelman et al., 2010; Kwan et al, 2010; Race et al., 2011) • Do amnesic people also have difficulty with ToM?

  16. Study 1 • Participants: • H.C., an individual with amnesia • A group of demographically matched controls Rabin et al., 2012, Neuropsychologia, see also Rosenbaum et al., 2007, Science

  17. Patient H.C. • 20-year old woman • Hypoxia one week after birth • 30 - 50% bilateral hippocampal volume loss (Olsen et al., 2013) • Therefore, she never developed normal episodic memory (Rosenbaum et al., 2011) • Graduated from a mainstream high school and completed one year of technical college

  18. Patient H.C. cont.

  19. ToM Tests • Tested H.C. and controls on a battery of ToM tests • Same ToMtests that have been shown to activate the core network of regions involved in EM (Buckner & Carroll, 2007; Spreng et al., 2009) • ToMtests that are sensitive to ToM impairment in a variety of patient groups (Gregory et al., 2002; Stone et al., 1998; Stone et al., 2003; Stuss et al., 2001) Rabin et al., 2012, Neuropsychologia, see also Rosenbaum et al., 2007, Science

  20. Mind in the Eyes Test Hateful Jealous Arrogant Panicked Rabin et al., 2012, Neuropsychologia, see also Rosenbaum et al., 2007, Science

  21. Mind in the Eyes Test Hateful Jealous Arrogant Panicked Rabin et al., 2012, Neuropsychologia, see also Rosenbaum et al., 2007, Science

  22. Faux Pas Task Jill had just moved into a new apartment. Jill went shopping and bought some new curtains for her bedroom. When she finished decorating the apartment, her best friend, Lisa, comes over. Jill gives her a tour of the apartment and asks, "How do you like my bedroom?" "Those curtains are horrible," Lisa replies. "I hope you're going to get some new ones!" Did anyone say something they shouldn't have said or something awkward? If yes, ask: Who said something they shouldn't have said or something awkward? Why shouldn't he/she have said it or why was it awkward? Why did they say it?

  23. Study 1: Results & Discussion • H.C. performed at the same level as controls on all ToM tests • Suggests that EM is not necessary for ToM, at least as measured by standard tests • H.C. may be relying on her intact semantic knowledge to perform these tasks Rabin et al., 2012, Neuropsychologia, see also Rosenbaum et al., 2007, Science

  24. Study 1: Results & Discussion cont. • Activation of a particular region during a task does not necessarily indicate that the region is necessary for that task • Activation of the hippocampus during ToM, does not necessarily mean that the hippocampus is necessary for ToM

  25. Outline Study 1: Is ToM impaired in amnesia? Study 2: What are the unique neural correlates of EM and ToM? Study 3 and 4: Are there certain conditions under which ToM depends on EM?

  26. Study 2 • Evidence of a shared brain network underlying EM and ToMbased on independent fMRI studies (Buckner & Carroll, 2007; Spreng et al., 2009) • Objective: To investigate EM and ToM in the same study using the same participants • Goal 1: Replicate the common pattern of activity observed across studies • Goal 2: Are there differences in activation? • Naturalistic paradigm using closely matched conditions

  27. Study 2: Details Participants: • 18 healthy, middle aged adults (9 males; 9 females) • Mean age = 57.2 years; SD = 8.0 years;

  28. Family Photos Paradigm Rabin et al., 2010, JOCN

  29. Family Photos Paradigm EM ToM Participant Unfamiliar people Rabin et al., 2010, JOCN

  30. Family Photos Paradigm EM ToM Participant Unfamiliar people Rabin et al., 2010, JOCN

  31. Family Photos Paradigm EM ToM Participant Unfamiliar people Create a novel event and focus on what one person in the photo was thinking and feeling at the time. Recall each event in as much detail as possible and focus on what you were thinking and feeling at the time. Rabin et al., 2010, JOCN

  32. Task 20 sec Button Press Rabin et al., 2010, JOCN

  33. Task Construction Phase Elaboration Phase 20 sec Button Press Rabin et al., 2010, JOCN

  34. Post Scan Interview Viewed the same photos they saw in the scanner Rate the vividness of each EM and ToMevent they generated in the scanner 0 1 2 3 4 5 6 vague vivid Rabin et al., 2010, JOCN

  35. Post Scan Interview Viewed the same photos they saw in the scanner Rate the vividness of each EM and ToMevent they generated in the scanner 0 1 2 3 4 5 6 vague vivid Rabin et al., 2010, JOCN

  36. Common Areas of Activation EM EM Base ToM ToM Base Rabin et al., 2010, JOCN

  37. Common Areas of Activation EM EM Base ToM ToM Base Rabin et al., 2010, JOCN

  38. Common Areas of Activation EM EM Base ToM ToM Base Rabin et al., 2010, JOCN

  39. Common Areas of Activation EM EM Base ToM ToM Base Rabin et al., 2010, JOCN

  40. Differences in Activation Construction Phase • All regions activated were engaged to a greater extent during EM vs. ToM Rabin et al., 2010, JOCN

  41. Differences in Activation Elaboration Phase EM • Midline regions showed greater activity during EM • Self-related processes (Craik et al., 2002) • Realness of events (Summerfield et al., 2009) • Lateral regions showed greater activity during ToM • Involved in semantic memory (Martin & Chao, 2001) ToM Rabin et al., 2010, JOCN

  42. Differences in Activation Elaboration Phase EM • Midline regions showed greater activity during EM • Self-related processes (Craik et al., 2002) • Realness of events (Summerfield et al., 2009) • Lateral regions showed greater activity during ToM • Involved in semantic memory (Martin & Chao, 2001) ToM Rabin et al., 2010, JOCN

  43. Differences in Activation Elaboration Phase EM • Midline regions showed greater activity during EM • Self-related processes (Craik et al., 2002) • Realness of events (Summerfield et al., 2009) • Lateral regions showed greater activity during ToM • Involved in semantic memory (Martin & Chao, 2001) ToM Rabin et al., 2010, JOCN

  44. Differences in Activation Elaboration Phase EM • Midline regions showed greater activity during EM • Self-related processes (Craik et al., 2002) • Realness of events (Summerfield et al., 2009) • Lateral regions showed greater activity during ToM • Involved in semantic memory (Martin & Chao, 2001) ToM Rabin et al., 2010, JOCN

  45. Differences in Activation Elaboration Phase EM • Midline regions showed greater activity during EM • Self-related processes (Craik et al., 2002) • Realness of events (Summerfield et al., 2009) • Lateral regions showed greater activity during ToM • TPJ is a key region involved in ToM(Saxe et al., 2006) • VLPFC and lateral temporal cortex; regions known to support semantic memory (Martin & Chao, 2001) ToM Rabin et al., 2010, JOCN

  46. Differences in Activation Elaboration Phase EM • Midline regions showed greater activity during EM • Self-related processes (Craik et al., 2002) • Realness of events (Summerfield et al., 2009) • Lateral regions showed greater activity during ToM • TPJ is a key region involved in ToM(Saxe et al., 2006) • VLPFC and lateral temporal cortex; regions known to support semantic memory (Martin & Chao, 2001) ToM Rabin et al., 2010, JOCN

  47. Differences in Activation Elaboration Phase EM • Midline regions showed greater activity during EM • Self-related processes (Craik et al., 2002) • Realness of events (Summerfield et al., 2009) • Lateral regions showed greater activity during ToM • TPJ is a key region involved in ToM(Saxe et al., 2006) • VLPFC and lateral temporal cortex; regions known to support semantic memory (Martin & Chao, 2001) ToM Rabin et al., 2010, JOCN

  48. Study 2: Discussion • Replicated common network supporting EM and ToM • Healthy people may rely on EM during ToM • For the first time showed differences between the two • Lateral regions engaged during ToMare the same regions known to support semantic memory • Rely on scripts/schemas about how the average person would respond in a given situation • Amnesic patients may rely on these lateral regions to carry out ToM tasks

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