---antergrade amnesia--- Flashcards
anterograde amnesia
having difficulties forming memories after amnesia sets in
unable to form new memories
- Patient H.M.
- Milner, Corkin, and Teuber (1968).
- In general, very little retrograde amnesia.
- Can remember people who were famous before 1953 (Marslen-Wilson & Teuber, 1975).
- Severe but not total anterograde amnesia.
- e.g. could also remember 20% of people who became famous after 1953 (e.g. JFK, Ronald Reagan).
N.A. (Teuber, Milner & Vaughan, 1968).
- Persistent anterograde amnesia after stab wound of the basal brain.
- Fencing foil entered the brain through the right nostril.
- Verbal material was more affected than nonverbal.
- Perception and vigilance were intact.
- There were no seizures or seizure-equivalents, and in this respect the patient’s condition differed from that of H.M.
- Mild retrograde amnesia (last 6 months).
- Almost total anterograde amnesia.
was able to perform day-to-day activities, if instructed and/or inspired to do them.
the complexity of amnesia
- If life were simple then
- Retrograde amnesics would lose memory for everything which happened in the past.
- Anterograde amnesics wouldn’t be able to learn anything new.
- But amnesia is not that simple!…
intact implicit memory
- Claparede’s (1911) amnesiac patient.
- Patient could not recognise Claparede, he had to reintroduce himself every few minutes.
- One day he pricked the patient’s hand while checking her hand with hidden pin!
- Patient did not want to check his hand anymore!
intact implicit priming
- Perceptual priming
- List of words
- Word identification under fast exposure
- Cermak, Talbot, Chandler and Wolbarst (1985)
- Amnesics learned a series of pseudowords
- Afterwards cannot distinguish well between those presented and filler words
- Presented words still better recalled in a priming task
- Amnesics showed a typical priming effect, even though much worse explicit memory for the prime list words
Evidence for intact implicit learning?
Cermak, Talbot, Chandler and Wolbarst (1985):
Participants (either alcoholic Korsakoff patients or controls) were presented with a list of 10 words to be remembered. Each word was presented individually for 5 seconds, with a 5-second interval between each word. This was termed the ‘study phase’. Participants were instructed to say the word aloud and to try to remember it.
procedural memory
Skills
Schacter (1983) - Tested an amnesiacs memory in a naturalistic setting – playing - Golf!
Memory for the events of the round was severely impaired. (e.g., number of strokes, where the ball went after the tee)
Extensive general knowledge of golf and played the game with a substantial degree of skill.
▪ Old Skills were preserved
new skills can also be learnt
Dana (1894) - patient learnt to play billiards
Starr and Phillips (1970) - patient learnt new piano pieces
how do we measure procedural memory
- Mirror writing task.
- Participant draws between the lines until navigated around the shape.
- Unfamiliar visual feedback.
- We can test how long it takes for amnesiacs to learn these skills in comparison to controls and whether they remember them!
- Slower learning rate than controls.
- Did not remember doing the task on each subsequent day.
- Learning also less flexible.
semantic vs episodic memry
- Are semantic and episodic memory differentially affected in amnesia?
- Problems in defining semantic memory (Baddeley, 1984).
- Semantic memories linked to episodic memory.
Semantic vs episodic memory: retrograde amnesia
- In retrograde amnesia, does this selectively hit episodic or semantic memory?
- Butters (1984).
- See earlier slide on PZ (a professor who wrote his memoirs just before getting Korsakoff’s amnesia).
- Showed an identical temporal gradient for semantic and episodic information, suggesting that he had lost both in parallel and the two may be reliant on each other.
• Patient K.C. (Tulving, 2002; Rosenbaum et al., 2009)
- Damage to cortical and subcortical regions including medial temporal lobes.
- No episodic memory (no personal events).
- Semantic knowledge intact (history, geography, etc.).
- Yasuda, Watanabe and Ono (1997).
- Patient M.N. – bilateral lesions to the temporal lobe.
- No memory of public events, historical figures.
- Reasonable episodic memory.
- A Double Dissociation
Patient K.C. cannot remember any events from his own life, with the exception of the last couple of minutes that are still accessible to him.
He posses some fragmented general knowledge of his past, but cannot recall a single episodic memory
Semantic vs episodic memory: anterograde amnesia
- In Anterograde amnesia, can amnesics learn new episodic and semantic information?
- Spiers, Maguire and Burgess (2001).
- Reviewed 147 amnesiac cases.
- In all cases episodic memory was impaired.
- Many patients – only modest impairment to semantic memory.
- Suggests these types of memory are distinct.
episodic memory deficits supported by semantic memroes
- Case of Jon (Vargha-Khadem et al., 1997, 2001, 2002).
- Brain damage at age 4 – led to hippocampus being ½ size of that in a healthy brain.
- This occurred before semantic memories had developed.
- Poor episodic memory for days events, but fine subsequent semantic memory (Age 20, high IQ and good semantic memory).
- Some evidence that used semantic memory to boost episodic recall.
- Very strong evidence for separate episodic and semantic systems.
- Probably because damage was more localised in the hippocampus in Jon compared to other amnesics which also often have damage in underlying cortices (entohinal, perihinal, parahippocampal cortices) which is associated with sematic memory.
