Task 1 Flashcards
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
Prefrontal cortex during WM
-monkey experiment
- cells are highly activated during delay period (monkey experiment)
- > can be active up to 1 minute
- involved in maintaining cue related info about visual field location
- activity represents combination of visual memory and motor planning
Executive functions - W.M.
- miller experiment
- showing monkey pictures (butterfly)
- protecting memory from interference
- miller study
- showing visual pictures to monkey
- cells are preferentially active to particular picture (butterfly)
- if information is removed ( no picture at all is represented)
- > cell that likes butterfly tries to keep info active
- > miller propose that PFC has ability to sustain activity despite distractions
-> activity in visual areas was very easily disrupted by distracting info (when pictures of butterfly etc were not shown)
Long term memory =
- lasts out working memory
- in many cases, LTM is associative/context dependent
Short term plasticity
- strong pre-synaptic stimulation leads to functional (post) synaptic changes
- post synaptic response gets potentiated to pre synaptic output
- lasts for minutes to few hours
Cooperatively
- multiple temporally coinciding small inputs can lead to depolarization & LTP
- > forms an memory , hippocampus forms an Engram
A popular working memory paradigm
- delayed saccade task
- monkey fixates a cross in the middle
- somewhere on the screen a square is presented
- then square disappears
- monkey is supposed to look at the place where the square was -> so the remembered location
- some neurons respond only to sensory onset of cue
- some respond after eye movement is made
- other neurons respond to delay!
- > but not sure if this is actually working memory , visual representation
- > Delay response is spatially specific but is it perhaps related to motor preparation?
- > anti saccade task: monkey is supposed to look in other direction of where cue was presented
2 results:
- > results show that it’s not spatial WM
- > show it IS spatial WM
- Could the Delay activity maintain object information rather than just spatial information?
- object related delay activity
