Clinically Relevant Functional Neuroanatomy 2: Neuroanatomy of Memory

1. Clinically Relevant Functional Neuroanatomy 2: Neuroanatomy of Memory Russell M. Bauer, Ph.D. University of Florida Functional Human Neuroanatomy 3 August, 2006

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

3. Multiple Forms of Memory

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

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

8. Temporal Lobe Pathology Associated with Herpes Simplex Encephalitis

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

13. Bauer, Grande, & Valenstein, 2003

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

16. CA3 CA1 DG subic

18. Bauer, Grande, & Valenstein, 2003

22. Delayed Nonmatching to Sample

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

24. 6-8 weeks postsurgery 2 years postsurgery

26. Anterior Posterior Zola-Morgan & Squire, 1990

27. Bauer, Grande, & Valenstein, 2003

28. Zola-Morgan & Squire, 1990

29. Murray & Richmond, Curr Opin Neurobiol, 2001 -perirhinal cortex obviously important in memory, but also apparently important in fine-grained visual discrimination

30. 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)

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

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

34. Lesion Profile in a Case of Thalamic Amnesia

35. Graff-Radford, et al, 1990

36. 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 Lateral Medial (Papez)

37. 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

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

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

42. Encoding • Definition: process of transforming to-be remembered in formation into memorable and retrievable form • Encoding I: bringing information-processing capacity to bear on stimuli • Encoding II: ability to use the results of E-1 mnemonically • Relevance: levels-of-processing accounts of memory (memory as by-product of information processing) • Clinical manifestation: poor immediate (superspan) recall

43. Consolidation/Storage • definition:process of making new memories permanent • basis:anatomic and physiological changes at cellular level; hippocampalsystem important • when?during study-test interval • duration:hours? days? years? • clinical symptom:delayed memory <<immediate memory (forgetting)

44. Retrieval • definition:process of locating, selecting, and activating a memory representation • basis: re-enactment of pattern of excitation occurring at encoding • when? at point of test • clinical symptom: recall << recognition (also true of shallow encoding), inconsistent errors

45. Key Points • Extended memory systemincluding hippocampus, amygdala, and basal forebrain • We (basically) understand anatomy, now we need to understand computation • Notion ofdistinct subtypes of amnesia generally less favorablenow than 10 years ago • Certain structures are‘wired’ for associational processing; these structures are reciprocally connected to cortical processors