Memory and its Disorders: The Three Amnesias

1. Memory and its Disorders: The Three Amnesias Russell M. Bauer, Ph.D. University of Florida Human Higher Cortical Function March 24, 2008

2. The Three Amnesias Russell M. Bauer, Ph.D. (DON’T BELIEVE HIS LIES)

3. Where’s the Lesion? • Patient presents to you with memory complaints. • Where’s the lesion? • Answer: Above the cervical vertebrae.

4. Where’s the Lesion? • Patient presents to you with a severe and profound impairment in the ability to remember new information that disables them in everyday life. • Where’s the lesion? • Answer: In an extended memory system that involves a cortical-subcortical network including the medial temporal lobe, thalamus, basal forebrain, and their interconnections

5. The Human Amnesic Syndrome • Impaired new learning (anterograde amnesia), exacerbated by increasing retention delay • Impaired recollection of events learned prior to onset of amnesia (retrograde amnesia), often in temporally graded fashion • Not limited to one sensory modality or type of material • Normal IQ, attention span, “nondeclarative” forms of memory

6. Multiple Forms of Memory Familiarity (not deliberate or conscoius) Recollection (deliberate, conscious)

8. IntegratedCircuitry Linking Temporal, Diencephalic, and Basal Forebrain Regions

9. Medial Temporal Syndromes • Anoxic-hypoxic syndromes • cardiac arrest • CO poisoning • Amnesia associated with ECT • CNS Infections (Herpes) • MTS and complex-partial epilepsy(material-specific) • MCI/Early AD

10. Temporal Lobe Pathology Associated with Herpes Simplex Encephalitis

11. Patterns of Atrophy in Subtypes of MCI Amnestic-Single Domain (88) Amnestic-Multiple Domain (25) Nonamnestic-Single Domain (25) Nonamnestic-Multiple Domain (7) Whitwell, et al. (2007). Arch Neurol, 64(8), 1130-1138.

12. The Case of Henry M (H.M.)

15. Bauer, Grande, & Valenstein, 2003

16. IntegratedCircuitry Linking Temporal, Diencephalic, and Basal Forebrain Regions

17. Two Limbic Circuits Anterior Thalamus Dorsomedial Thalamus Mamillothalamic Tract Mammillary Bodies Cingulate Gyrus Orbitofrontal Amygdalofugal pathways Fornix Uncus Hippocampus Amygdala Lateral Medial (Papez)

19. CA3 CA1 DG subic

20. Classical Trisynaptic Circuit

22. Bauer, Grande, & Valenstein, 2003

23. 2 x 103 each <100 each <100 each

24. Long-Term Potentiation (LTP)

27. Delayed Nonmatching to Sample

28. Delayed Nonmatching to Sample, multiple trials, trial-unique objects

29. 6-8 weeks postsurgery 2 years postsurgery

30. Anterior Posterior Zola-Morgan & Squire, 1990

31. Bauer, Grande, & Valenstein, 2003

32. Zola-Morgan & Squire, 1990

33. Murray & Richmond, Curr Opin Neurobiol, 2001

34. Two Limbic Circuits and the Two-system theory of amnesia Anterior Thalamus Dorsomedial Thalamus Mamillothalamic Tract Mammillary Bodies Cingulate Gyrus Orbitofrontal Amygdalofugal pathways Fornix Uncus Hippocampus Amygdala PRPH Lateral Medial (Papez)

35. Recollection v. Familiarity Figure 3. Anatomy of the MTL region. (a) Approximate locations of the hippocampus (red), the PRc (blue) and the PHc (green) shown on T1-weighted magnetic resonance images. (b) Representation of the anatomical connections among, and the proposed roles of, the hippocampus, PRc and PHc in episodic memory according to the BIC model. The arrow between the PRc and PHc indicates the anatomic connection between the two regions; the PRc receives more inputs from the PHc than vice versa. The connections shown here are based on results from anatomical studies of rats and monkeys. Diana, Yonelinas, and Ranganath, TICS, 2007)

36. Figure 1. Activation of MTL subregions in studies of recollection and/or familiarity. Shown is the percentage of contrasts of each type (recollection, familiarity or associative recognition) in which activation was reported for the hippocampus, the posterior parahippocampal gyrus (PPHG) and the anterior parahippocampal gyrus (APHG). Data are summarized from Tables 1 and 2. Recollection v. Familiarity Diana, Yonelinas, and Ranganath, TICS, 2007)

37. Diencephalic Syndromes • Korsakoff Syndromeassociated with ETOH abuse or malabsorption • prominent encoding deficits • role of frontal pathology • Vascular disease • Thalamic trauma

38. Mamillary Body Lesions in a case of Korsakoff’s Disease

40. Lesion Profile in a Case of Thalamic Amnesia

41. Graff-Radford, et al, 1990

42. Two Limbic Circuits and the Two-system theory of amnesia Anterior Thalamus Dorsomedial Thalamus Mamillothalamic Tract Mammillary Bodies Cingulate Gyrus Orbitofrontal Amygdalofugal pathways Fornix Uncus Hippocampus Amygdala PRPH Lateral Medial (Papez)

43. IntegratedCircuitry Linking Temporal, Diencephalic, and Basal Forebrain Regions

44. Basal Forebrain Syndromes • Anterior Communicating Artery (ACoA) infarctions • prominent anterograde, variable retrograde amnesia • prominent confabulation • frontal extension of lesions • Basal forebrain and cholinergic projections to hippocampus

46. Hippocampal Damage: Hypoxic Injury Basal Forebrain Damage due to ACoA Rupture Myers, et al. (2006). Neuropsychologia, 44, 130-139.

47. Qualitative Differences between MTL and ACoA patients in conditioned reversal (Myers, et al., 2006) Cheese on right if background is light; on left if dark (reversal = opposite) Acquisition Reversal

48. Two Limbic Circuits and the Two-system theory of amnesia Anterior Thalamus Dorsomedial Thalamus Mamillothalamic Tract Mammillary Bodies Cingulate Gyrus Orbitofrontal Amygdalofugal pathways Fornix Uncus Hippocampus Amygdala PRPH Lateral Medial (Papez)

50. Two Limbic Circuits Anterior Thalamus Dorsomedial Thalamus Mamillothalamic Tract Mammillary Bodies Cingulate Gyrus Orbitofrontal Amygdalofugal pathways Fornix Uncus Hippocampus Amygdala PRPH Lateral Medial (Papez) Bauer, Grande, & Valenstein, 2003