Chapter 11: Amnesia Flashcards
Describe types of amnesia: retrograde, anterograde (post-traumatic amnesia), transient global amnesia
~Retrograde: loss of access to event s that happened in the past, prior to a trauma
~Anterograde: a deficit encoding, storing, or retrieving new events occurring after a trauma
-Transient global amnesia: sudden impairment forming and retrieving new memories
-tends to resolve rapidly
-develops rapidly in apparently normal individuals
-cause is yet unclear
Describe main goals of the three approaches to studying amnesia: neurosurgical, pathological, and cognitive.
- Neurosurgical: anatomical localization to guide neurosurgical treatment
- Pathological: develop a better understanding of a specific disease with its many complexities
- Cognitive: focus on pure and theoretically important deficits
What do anterograde amnesiacs have deficits in?
~episodic learning:
- visual and verbal - recall and recognition
What is typically preserved in anterograde amnesiacs?
~intellect and language
~nondeclarative memory
-classical conditioning: handshake study, avoidance conditioning pairing a light with a puff of air so that the light elicits blink response
-priming
-motor skills
-controlling complex systems
-hedonic adaptation
~digit span
~normal recency effect in free recall (no primacy effect doe)
~Brown-Peterson short-term forgetting task that there is no frontal lobe damage
Describe theories of amnesia that aren’t true.
~Levels of processing deficit
-Korsakoff patients are helped by deep encoding instructions and humorous materials
~Faster forgetting is also not likely
-Hypothesis: LTM traces decay especially rapidly in amnesiacs
-Test: after equating the initial level of learning, the rate of forgetting remains constant
~Retrieval interference
-Hypothesis: w/o hints like word stem, amnesiacs are overwhelmed by interfering alternatives
-Later conclusion: since explicit instructions using the word stems did not benefit retrieval, rejected hypothesis
Describe the assumptions and predictions of the contextual processing theory of amnesia.
Assumption: individual episodes are linked to specific time and place of the experience
-Allows selective retrieval of specific memories
Prediction: inability to link experience to spatio-temporal context would disrupt recollection
Give human evidence for the contextual processing account of amnesia.
Task: amnesiacs and controls saw pictures either once or twice on successive days and were asked on which day they saw the picture
Results:
~Amnesiacs more likely to say doubly-presented items from Day 1 were presented more recently on Day 2
-relied on familiarity in the absence of context
~Controls more accurate in dating if presented twice
-added repetitions increased contextualization
So? Amnesiac patients have source amnesia
-bad at recalling when source info is required
-tend to confuse recency with degree of familiarity
Give assumptions of modal model of amnesia. How can it be tested?
Assumptions:
~Episodic memories are normally consolidated when a mnemonic glue binds items together with their contexts
~Recall and recog involve same underlying storage processes (but place different constraints on subsequent retrieval)
~Semantic memory represents the residue of many episodes
-over time, individual episodes may be forgotten
-features shared by the repeated episodes can still be retrieved by a separate semantic system
Testing
-given generalities of model, it is difficult to test
-cases of developmental amnesia cast doubt on the main assumptions of the model
What was impaired and unimpaired in Jon?
remember, Jon had damage to hippocampus as an infant
Impaired: ~learning ~recall Unimpaired: ~recognition ~above average intelligence ~good semantic memory skillz
How does Jon pose problems for the modal model of amnesia?
~Semantic memories depend on episodic memories BUT Jon could not form episodic memories and had normal semantic memory
~Crystallized intelligence from prior learning should be impaired BUT Jon has normal intelligence and roughly average linguistic abilities
~Recall and recognition essentially same BUT Jon has good recog despite strong recall impairment
Describe difference between remembering and knowing.
~Remembering: recollecting a learning episode
-traveling backward in time to re-experience the event
~Knowing: familiarity with a learning episode without the recollective experience
Can Jon experience remembering?
~No! Jon can learn by building up familiarity so that he knows information
~However, he has difficulty remembering
-He would use familiarity strength as a stand-in for recollection
-Generally lacks electrophysiological and neuroimaging signatures of remembering
-subsequent evidence suggests a lingering ability to recollect a few memories
How can we quantify the degree of retrograde amnesia? What are some problems with these first methods?
First attempt:
~Task: presented patients with photos of people famous at specific points in time
~General findings:
-Amnesiacs perform more poorly than controls
-Earlier memories better preserved (Ribot’s law)
Similar scales using: news events, horsie races, TV shows aired for 1 season
Problems:
~Degree of knowledge of the events is likely to vary across patients
~Scales require continuous updating to add new, relevant events
Describe the probe method of evaluating RA.
~Probe patient’s memory for autobiographical recollections
-validate memories with family/caretakers
-Galton provided cue words to spark memories, and similar methods used on patient RA
BUT, hard to code
Describe the autobiographical memory interview. (semantic vs. personal autobiographical scale)
~Semantic scale: asked to remember specific factual information from certain time periods
~Personal autobiographical scale: also asked to recollect a specific personal event from each period
-rated for amount and specificity
Valid, sensitive, and reliable, and doesn’t needa be updated all the fuggin time
