Lecture - learning and memory Flashcards
learning
Changes in our nervous system as a result of experience
memory
How these changes are maintained over time and how they are expressed (recall)
amnesia
incapacity to remember
retrograde amnesia
Inability to remember events prior to injury (i.e., some sort of damage to your brain). Can’t remember the past.
anterograde amnesia
Inability to remember events after injury. Incapacity to form new memories.
Bilateral Medial Temporal Lobectomy (HM case)
Removal of the medial temporal lobe (MTL) bilaterally to alleviate serious epilepsy (1953). included the hippocampus, amygdala, rhinal cortical areas. Epilepsy improved, but had devastating amnesic effects.
after surgery (HM case)
Intellect was above average, IQ actually improved from 104 to 118. Normal perceptual and motor abilities and a well-adjusted individual. but, he was left with very poor memory abilities. Mild retrograde amnesia (~ 2 years prior to surgery) and profound anterograde amnesia.
HM
- HM is the most famous patient in the history of neuroscience research.
- He has made a valuable contribution to research on the neurobiology of memory. He has been extensively tested for over 50 years.
- Demonstrated that the medial temporal lobe is critical for forming new memories.
what can HM do
Remember a list of 6-7 digits.
- Digit-Span + 1 Test
- Performance in normal range.
Tap a sequence of 5 blocks
- Block-Tapping Memory Span Test
- Performance in normal range.
So, HM has relatively intact short-term memory.
HM can learn new behavioral skills
Mirror-Drawing Task and Rotary-Pursuit Test:
- HM’s performance improves with training sessions. Normal sensory-motor learning. He has no conscious recollection of ever performing it before.
HM can show normal priming
More likely to use a word if you have heard it recently. Repetition Priming Test: He has no conscious recollection of the words on the original list.
HM can learn conditioning tasks
Pavlovian Conditioning: HM’s performance improves with training sessions. He has no conscious recollection of ever performing it before.
what HM has taught us
- Evidence that there are different kinds of memory.
- Different brain regions are more important for some kinds of memory, but not others.
- Consolidating episodic memories depends on the medial temporal lobe.
- Evidence for two parallel memory systems.
how long does short term memory last
seconds - minutes (okay in HM)
how long does long term memory last
hours - years (sort of okay in HM; can form some kinds of long-term memories).
working memory
active maintenance (okay in HM)
declarative (explicit) memory
things you know that you can tell others
episodic (explicit)
impaired in HM
semantic (explicit)
okay in HM
procedural (non-declarative, implicit)
things you know that you can show by doing.
skill learning (implicit)
okay in HM
priming (implicit)
more likely to use a word you heard recently. okay in HM
conditioning (implicit)
okay in HM
Although subjects with MTL amnesia can form procedural (implicit) memories
they can not transfer that memory to a new or different context (situation)
The conscious (explicit) system may have evolved to confer
flexibility, that is, ability to use implicit learning in different ways or contexts.
memory storage equals
memory consolidation.
storing (consolidating) memories
Change the memory from a labile/vulnerable state to a stronger, more permanent state.
Concussion or Coma (closed head trauma)
Usually results in amnesia for events occurring just after regaining consciousness. Failure to convert short-term memories to long-term memories. Permanent retrograde amnesia for events just prior to the injury. Older memories are spared! Suggests that these memories have been protected by some mechanism and are stronger than newly formed memories.