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Department
Psychology
Course
PSYC 2650
Professor
Dan Meegan
Semester
Fall

Description
Amnesia 10/11/2012 3:18:00 PM Amnesia Neuropsychology:  Amnesia  Memory distinctions (different hypotheses) Amnesia: Causes of Amnesia  Head Injury (even in fairly mild cases)  Cerebral vascular incident (e.g., stroke, aneurism [cell loss and or increase in brain pressure, not just memory impairments])  Epileptic activity (Mike in video, temporal lobe also a common focal point for epilepsy)  Electroconvulsive Therapy (done deliberately)  Neurosurgery (H.M. became amnesic because of surgery for seizures)  Tumors (just like blood, increase in pressure and death of cells)  Chronic alcohol abuse (Korsakoff’s syndrome, vitamin B)  Alzheimer’s Disease (most prominent symptom of AD)  etc. Symptoms: Definitions  Anterograde amnesia (AA): inability to learn new things, or remember information learned after the onset of amnesia o Leonard from Memento, can have something in STM but fail to put it into LTM o Hippocampus damage (role in memory acquisition)  Retrograde amnesia (RA): difficulty in remembering events that occurred before the onset of amnesia o Losing one’s past Head Injury  Often experiences both AA and RA  Most likely reason for young people to have amnesia  Recovery with time (in many cases, especially ability to create new memories) o There will still be period in which they could not commit memories to LTM (when still regaining abilities)  Can commit pictures from events missed to LTM  Permanent loss of memory for events preceding injury (RA) and for events occurring during time of AA  Symptoms not limited to memory loss  Particular case study in case of traumatic head injury (7 week coma)  Time L-R  What we know about individual’s memory abilities at different times  A) Would not remember anything and no memory for anything 2 years prior to injury o Gross disturbance: temporal gradient, more likely to forget recent past (counter intuitive)  B) During 3 months, beginning to recover new memories, RA reduced and 4 years of patch memory prior to RA period  C) Now memory is precise (back to normal), still 23 week period of memory loss Neurosurgery  HM was a severe epileptic whose seizures originated in the medial temporal lobe  Bilateral (both sides) medial (towards middle) temporal lobectomy (to remove a lobe)  Successful surgery as far as epilepsy goes but developed severe AA o Surgery was never done afterwards  RA period of 3 years preceding surgery  Diagnosis  Korsakoff’s syndrome Korsakoff’s Syndrome  Chronic alcohol abuse can lead to vitamin B1 (thiamine) deficiency that causes brain damage, particularly to areas involved in memory  AA and RA  Unconscious awareness o Patient shakes hand and gets shock, next time sees person, does not remember them but knows not to take their hand (doesn’t know why though) o Trivia question set, if did not know the answer would be told and question replaced in stack, patient would eventually encounter the same question again and more likely than not got it right (had no recollection of learning the material) o Listened to melodies, then given list of melodies and they were asked which one they had heard before (performed poorly) then asked which one they preferred more and often chose familiar tune (not direct testing rather a preference)  No explicit memory but some implicit memory Alzheimer’s Disease  A wider range of memory impairments than other amnesic populations  A steady deterioration, with memory impairment in the early stages being followed by other cognitive impairments  Very broad as to how it effects the brain (not great to study specific brain damage and to understand distinct memory systems) Why are cognitive psychologists interested in amnesia?  Memory is too complex to be a single process in an information- processing model  Double dissociations… o Say that there are memory processes A and B (not necessarily damaged process A or B, maybe inability to or poor processes) o Could have 1 memory system, and memory processes are due to different tasks  Tasks that require most attention / hardest are first to go in memory damage Widespread brain damage…  less likely to make proof that there are 2 different memory processes (AD) Is STM distinct form LTM?  There are many amnesiacs with profound LTM deficits but with intact STM o LTM is harder than STM therefore first to go and more common in patients (Leonard in Memento) o Digit span: many amnesiacs are as good as “normal”  Test for STM o It is possible to have a normal conversation with most amnesic patients o AA only shows itself with sufficient delays (longer retention intervals)  Hold response for conversation in STM  STM intact, LTM deficient  There are a few reported cases of patients with STM deficits and intact LTM… (evidence for modal model) o Patient KF - brain injury from motorcycle accident o No difficulty on long-term learning and recall (normal performance) o Digit span was impaired (2 digits)  Normal in 7 +/- 2 o Small recency effect in free-recall  No second half to U function, more likely to recall first few words  This double dissociation was considered strong evidence for separate ST and LT memory storage (few suggest we have 1 memory system) o Difference between STM and LTM tasks  Digit span task is easy but as soon as you increase RI, becomes more and more difficult  Therefore law of parsimony  LTM deficits evidence is not impressive because first to go is the hardest things we tell memory to do  Importance of double dissociation Other Memory Distinctions (LTM): Episodic/Semantic
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