15_Anterograde.ppt

Anterograde Amnesia Retrograde Amnesia Impairment of memory for events before the injury. Anterograde Amnesia Impairment of memory for events after an injury. That is, an impairment in learning. Types by Duration Temporary Drug induced Lithium Alcohol tricyclic antidepressants e.g., valium (Judd et al. 1987) Shock/Trauma e.g., ECT used for depression Chronic Alcohol - reversible with abstinence (over years) Trauma ? e.g., injury, disease, toxins, anoxia Progressive Alzheimer?s Huntington?s Medial Temporal Amnesia 1 Bilateral damage to medial temporal region including hippocampus Medial Temporal Amnesia 2 Most famous cases are: H. M. (surgery) S. S. (encephalitus) R.B. (blood supply to area cut off by atrial tear) (Zola-Morgan, Squire, & Amaral, 1986). Medial Temporal Amnesia 3 The semantic (logogen) network remains intact. Normal intelligence Normal autobiographical memory (no RA) Normal implicit memory and priming effects observed (Graf, Shimamura, & Squire, 1985). Skill learning unimpaired. Patient?s skill improves despite being unable to recall having done the task before. Wernicke?s-Korsakoff (KD) Syndrome 1 Caused by thiamine deficiency that results from alcoholism and starvation MRI comparison with alcoholics shows damaged diencephalon Wernicke?s-Korsakoff Syndrome 2 As with Medial Temporal Amnesia, procedural and implicit memory are functional. Warrington & Weiskrantz (1970; 1974). Graf, Squire, & Mandler (1984). Gardner, Boller, Moreines, & Butters (1973). Nature of Learning Deficit Semantic Because the cortex is intact in medial temporal and diencephalic amnesia, semantic priming is normal. Hence, an individual will respond with a word she or he has recently heard in response to a specific cue without recognizing that he has recently been seen or heard. Orientation to time and place Consider what Leonard knows of his circumstances in Memento A person who cannot learn information must become lost, even if he or she never moves.