WEEK 7 CCC- 1 : LTM and Amnesia

Amnesia

  • HM

    • extreme epilepsy

    • had to undergo a surgery in which he lost his memory for events after the surgery

    • parts of his medial temporal lobe were removed - including the hippocampus

  • Amnesia is normally caused be damage in the temporal one or connected regions

    • HM had anterograde (meaning after the surgery amnesia)

    • he was impaired no matter what kind of memory test was given - recent occasions, recognitions, words, faces, etc.

    • verbal and visual STM

      • Digit Span (repeating numbers, tapping same blocks as interviewer)

    • Procedural memory

      • amnesiacs can learn new skills - mirror tracing (Corkin, 1968), controlling a joystick, mirror reading, etc.

    • Priming

      • degraded picture identification - Elizabeth Warrington

      • 5 amnesia patients

2 Types of LTM - Edsel Tulving (1972)

  • Episodic

    • memory for events that happened at a particular place and time.

    • impaired in amnesia

  • Semantic

    • knowledge about facts, concepts, word meanings, etc.

Memory for the past

  • retrograde means before brain injury

  • some retrograde memory loss is almost always present in amnesia

  • HM’s retrograde memory only had a few years

  • instead of retrieving memory from his hippocampus, as it was all connected before the circuit, HM is able to remember some information from the cortexes around the hippocampus as they held some information when connected with the hippocampus.

cortex → Hippocampus ← cortex

  • Standard Theory of Consolidation is controversial

    • semantic memories are likely to be consolidated

    • episodic memories may never be fully consolidated

    • retrograde amnesia for some things can last for decades

  • Impairments of semantic memory

    • semantic dementia

      • difficulty remembering the meaning of words or concepts

      • naming errors

      • problems nor confined to a single modality

      • semantic knowledge associated with lateral temporal cortex (on the left side).

LTM Processes

encoding → storage → retrieval

  • TEST

    • study lists of words and asked to made judgements about them

      • upper or over case letters?

      • does the word rhyme with plate?

      • does it fin in the sentence “…”?

    • memory improves depending on the processing used p there are different levels

  • Levels of Processing - Craik & Lockhart (1972)

    • processing can be deep or shallow

      • “deep encoding” - better way to learn and maintain information

    • reasoning for different levels is circular

    • 2 codings

      • semantic (deep): “the …. had a silver engine”

      • phonological (shallow): “… rhymes with legal”

    • 2 testing conditions

      • standard recognition

      • rhyming recognition

    • memory is better when processing matches between encoding and retrieval.

  • Context Dependent Memory

    • scuba diving ppts

    • learning list of words in land vs under water

    • remembering the list in land vs under water

    • better retrieval when conditions are matched

  • Retrieval Practice Effect

    • ppts tested to reread the passage after 5 min vs 2 days vs 1 week

    • studying and then testing yourself leads to much better retention.