Memory Systems Flashcards
Types of memory
- Declarative/explicit memory
- Nondeclarative/implicit memory
Declarative/explicit memory
- Localized to medial temporal lobe, especially hippocampus and diencephalon
- Facts and events
Nondeclarative/implicit memory
- Hard to learn, hard to forget
Procedural memory (localized to the striatum): skills and habits e.g. playing the piano
Classical conditioning (type of nondeclarative memory:
- Skeletal musculature (localized to cerebellum)
- Emotional response (localized to amygdala)
Declarative vs. nondeclarative memory
Declarative memory acts through conscious recollection – nondeclarative memories operate smoothly without conscious recollection
Declarative/explicit memory is localized to ___
Medial temporal lobe, especially hippocampus and diencephalon
Procedural memory is localized to the ___
Striatum
Skeletal musculature (type of classical conditioning) is localized to the ___
Cerebellum
Emotional responses (type of classical conditioning) is localized to the ___
Amygdala
Long-term memories
Can be recalled days, months, years after they’ve been stored and are only a fraction of what we experience
Short-term memories
Are vulnerable to disruption (head trauma, electroconvulsive therapy) that does not affect long-term memories
Memory consolidation
It is hypothesized that facts and events are stored in short-term memories and only a subset are converted to long-term memories through a process called memory consolidation
Suppose you were telling a friend about the amazing holiday cookie you ate the week before and you, ironically, trip on a large box of Girl Scout thin mints someone left on the sidewalk. You hit your head
and afterwards you are unable to recall the holiday cookie. Memory for the cookie was stored in what type of memory
a) Long term
b) Short term
c) working
B) short term
What is working memory?
An entirely different form of temporary shortage from short-term memories
Characteristics of working memory
- Only lasts for seconds
- Sharply limited in capacity and requires rehearsal ex. getting somebody’s
number - Commonly measured with digit span (max number of randomly chosen numbers read from a list that can be repeated back)
- More effectively held in mind through chunking (ex. breaking group of
numbers into meaningful groups (ex. 326-523-9843)) - Experimental evidence suggests digit spans in different modalities can be
separately damaged → there may be multiple temporary storage areas in the brain
How long does working memory last?
Seconds
Examples of experiments in working memory
- Delayed response task
- Identity & location tasks
Delayed response task
- Experiment Design: Monkey sees food be placed in one well → curtain closed for short delay period (monkey can’t see wells) → curtain reopens with wells covered → monkey chooses correct well with food in it
- What we learned: neurons in the prefrontal cortex showed activity during the delay period when the monkey must hold the information in working memory
Identity & location tasks
- Experiment Design: 2 types of tasks, identity and location tasks, where a participant must memorize the face or location of a face photo and then recall that after a short delay when tested
- What we learned: Delay-period activity found in different but overlapping areas for the two tasks → working memory delay activity exists at various brain locations depending on the task being done
What did the Delayed Response Task reveal about working memory?
a) Working memory is primarily stored in the hippocampus.
b) Neurons in the prefrontal cortex show activity during the delay period when information is held in working memory.
c) The task requires only short-term memory, not working memory.
d) The experiment showed that monkeys cannot retain information beyond a short delay.
B
What factors affect the consolidation process?
Salience and emotion
Consolidation of working and short-term memory
- Sensory info divided into working memory or short-term memory
- Short-term memory (hippocampus) is converted to long-term memory (cortex) through consolidation
- Working memory can apply things in long-term memory through retrieval
What structures does the medial temporal lobe include?
- Hippocampus
- Entorhinal cortex
Medial temporal cortex
- Includes hippocampus and nearby cortical areas such as the entorhinal cortex (functions as input to hippocampus)
- Critical for declarative memory formation and storage
Entorhinal cortex
Functions as input to hippocampus