Neurophysiology of Memory Flashcards
what is amnesia?
intelligence and attentional span is intact
personality is unaffected
ability to take in new information is severely and usually permanently affected
verbal and visual short term memory is intact (phonological store and visuospatial sketchpad intact)
what happened to HM?
underwent surgery to treat severe epilepsy
bilateral removal of medial temporal lobes, including hippocampus
completely lost memory for events after the surgery
what can cause amnesia?
usually caused by damage to medial temporal lobe or anatomically connected regions
can occur in head injuries, Alzheimer’s disease, epilepsy and stroke
what is anterograde amnesia?
cannot form new memories since injury occurred
episodic memories severely affected
Corkin: HM was severely impaired, no matter what memory test given - words, faces, tones, public events
regardless of sensory modality or test format
how can long term memory be divided?
declarative (conscious) and implicit (not conscious)
declarative includes episodic (personal events) and semantic (facts, knowledge) memories
implicit includes priming effects and procedural memory
what evidence is there for procedural memory?
amnesiacs can learn new skills - mirror tracing (Corkin), mirror reading (Corkin & Squire)
Butters et al: pursuit rotor task
healthy controls and patients with Alzheimer’s showed normal learning
patients with Huntington’s were impaired
evidence that procedural memory is independent
dedicated systems exist for procedural memory (basal ganglia)
what is episodic memory?
Tulving
memory for events and occurrences which are specific in place and time
‘what’ ‘where’ ‘when;
what is semantic memory?
Tulving
knowledge of facts, concepts, word meanings etc
cam be retrieved without knowledge of where and when the information was acquired
what is the declarative memory theory?
Squire
all declarative memories (episodic and semantic) depend on medial temporal lobes for their acquisition and short-term memory retention
what is the standard model of consolidation?
Squire
over time, declarative memories become consolidates to other brain regions (away from medial temporal lobes)
evidence that amnesiacs cannot form new semantic memories
Bayley et al
tested new vocab in adult amnesiacs
each test contained 1 target words and 8 foil words
amnesiacs couldn’t remember new vocab (compared to controls)
supported Squire’s declarative memory theory
evidence that amnesiacs can form new semantic memories
Vargha-Khadem
3 typical amnesiacs - damage to hippocampus just after birth
grossly impaired episodic memory but completed normal schooling, have good vocab and world knowledge
Sharon et al
new learning in adult amnesiacs
when learning was incidental names of objects could be remembered, but complete failure when explicitly asked to remember name
does not support Squire’s declarative memory theory
what is retrograde amnesia?
cannot recall events prior to brain injury
some degree is almost always present
extent of retrograde for episodic memory is highly contested
evidence that episodic memory for distant memory is intact
Bayley et al
8 amnesiac patients
semantic memory for past similar to controls
episodic memory sometimes better than controls
supports Squire’s standard model of consolidation
evidence that episodic memory for the distant past is not intact
Viskontas et al
25 patients with unilateral temporal epilepsy
investigated memory for 3 time periods in patients lives
episodic: amnesiacs perform worse than controls
semantic: amnesiacs and controls performed equally well
does not support Squire’s standard model of consolidation
