Working memory
- keep info active for short amount of time
- prefrontal cortex
- > after longer time -> activity in hippocampus
Encoding - 3 types
1) structural encoding: translating visual info into physical structure
2) phonemic encoding: translating visual info into sound
3) semantic encoding: translating visual info into meaning
Atkinson-Schiffrin Model
- sensory input goes to sensory memory
- through paying attention and repeated rehearsal information is kept in short term memory
- prolonged maintenance leads to automatic transfer to LTM
- info can be retrieved from LTM to STM
Controlled updating: N-back task
- delayed response task used to measure working memory activity and capacity
- N refers to the number of items that have to be held in WM
Stroop task
- used to study the mechanisms of stimulus selection/response inhibition
- color telling, ignoring text
Tower of Hanoi
- planning
- game requires several mental control mechanisms:
- what subgoals have been accomplished
- what subgoals remain
- what is the next subgoal
Wisconsin card sort test
- switching
- rules of game change in the process
Left hemisphere and working memory
-verbal WM
Right hemisphere
-visuo-spatial working memory
Dorsolateral prefrontal cortex
- associated with higher executive control functions
- damage: dysexecutive syndrome -> disrupts ability to plan and integrate new information
Ventrolateral prefrontal cortex (VLTPF)
-associated with encoding and retrieval
-> left VLPFC: phonological loop:
Anterior-> semantic
Posterior -> phonological
-> right VLPFC: visuospatial-spatial sketchpad
Consolidation period
-time where memories are still vulnerable to being forgotten or altered
Organization effect
- a story is read and a picture is shown either before reading, after or not at all
- > only participants seeing the picture BEFORE scored better in recalling
transfer appropriate processing
-things are more easily remembered when cues from the moment of learning are present
Transient memories
- sensory memories
- short-term memories
Sensory memories
- eg visual sensory memory: short representation of what just has been seen
- iconic memory: rapidly decaying visual sensory memory
- probably present for all senses
Short term memories
- maintained by active rehearsal and easily displaced by new information (distraction)
- limited in capacity and duration
Phonological similarity effect
-a series of letters is more easily recalled if they are different
Word-length effect
-the longer the words, the lesser words you can remember
Evidence for Baddeley Hitch Model
Articulacy suppression ?
-
Problem Atkinson-Shiffrin Model
- rehearsal does not ensure LT storage , rather Depth of Processing
- patients with damage to partial lobe were able to store information in LTM without having STM
Goldman -Rakic research monkeys
Various neuronal activity in DLPFC when:
- cue is presented
- during delay phase
- when ganze is shifted
-> ‘Delay-Neurons’ tuned to sensory and movement response
Schizophrenia
- tasks requiring activity of central executive are impaired
- phonological and visuospatial memory tasks are not impaired
- patients performing poorly in N-back task usually have a very high number of D1 dopamine receptors
ADHD
- generally tasks that require working memory are impaired
- neuroimaging indicated reduction in regions associated with working memory (right PFC)
- similar to schizophrenia dopamine irregularities seem to be at work
