W9 - Memory Flashcards
What are the main components in the original cognitive model (Baddeley and Hitch, 1974)
STM
- ) Phonological Loop
- ) Visuospatial Sketchpad
- ) Central Executive
What are 3 properties of the phonological loop
Phonological Loop
- Hold memory traces for few seconds before they fade (7 +- 2)
- Articulatory rehearsal process, like subvocal speech
- Limited capacity because articulation occurs in real time
- (as items increases, point reached when first item faded before latest item is rehearsed)
What are the 4 evidences to support existence of a phonological loop
- Phonological similarity effect
- Word-length effect
- Irrelevant sound effect
- Lesion
What is the task typically used in phonological loop and outcome factors
- Digit span task
- Examine how much load size
- Backwards digit span
- Central executive manipulation
What is the phonological similarity effect. Contrast this with LTM
Accurate recall:
- Similarity of sound is more important than meaning of sound
- vs LTM, where Meaning > Similarity
What is the word-length effect
- Span declines as word length increases from one to five syllabus
What is the irrelevant sound effect. What is the crucial requirement
- Impaired recall due to concurrent or subsequent presentation of irrelevant spoken material
- Includes speech, music
Crucial requirement:
- Fluctuation in state of irrelevant stimulus stream
What is lesion data evidence to support phonological loop
Patients with verbal deficit and broca area lesions in absense of an articulation deficit show:
- No phonological similarity effect
- No word length effect
- Appear to avoid articulation
What are properties of the visuo-spatial sketchpad.
What is the typical task?
What does the visuos-spatial sketchpad account for?
Task: Corsi blocks
- Limited capacity (4 +- 1 objects)
- Capaciy to hold and manipulate visuospatial representations
- Accounts for change blindness
- No distinction between vision and spatial (How do we imagine vision without a space?)
Verbal and Spatial WM architecture
Shared hemispheric and neuroanatomical archiecture for both verbal and spatial WM.
No hemispheric specialisation
What are properties of the central executive. What is the task?
Concept of the Homonculus:
- Divide, switch, focus attention
- Connects working memory and LTM
- Required for WM tasks that require manipulation of information held in storage
Tasks
- Orientation Span Task
- Backward digit span
Explain the orientation span task. Why is it used?
Orientation Span Task
- Reads the equation aloud as soon as it appears
- Indicate whether provided answer was correct and read the word at the end aloud
- Do an operation (phonological/visuo-spatial)
- Write down the five words in correct order
- OSPAN score = Sum of recalled words for sets recalled in perfect order
Why?
- Requires manipulation of information and storage in working memory
When do neurons fire in a WM task?
Cells in PFC specifically fired in the delay period of a delayed response test
Spatially selective DLPFC neurons in non-human primates show what pattern of activity
Persistent and location specific activity for a particular location in visual space during the delay period of a WM task
Persistent activity of PFC neurons in delayed period:
When does it persist (2 Things)
What happens if it does not?
When does PFC persist?
- Persist during delay period
- Persist during time epoch when representative is active
- Activity dissipates when representation is no longer needed
- If activity does not persist through retention interval, memory performance is compromised
Persistent activity of PFC neurons in delayed period:
Two more properties (2 things)
Properties:
- Magnitude of persistent activity commensurate or correlated with memory load
- Selective
- Spatially selective (Specific visual space)
- Subsequently identified PFC neurons selective for cues, delay, response
Does persistent activity represent maintainance of past stimulus?
What has it shown to represent?
And what does it suggest?
Persistent PFC activity for
- Visual stimuli in absense of WM demands
- Maintainance
- Anticipation of future stimulus
- Representing or Maintaining abstract information
- e.g. rules, associations, told to maintain
(a) Maintainance; (b) Manipuation; (c) Selection
Not represent
- Maintenance of physical stimulus presentation
Delay is Process of maintainance, not stimulus itself
Describe the Sternberg. What did the Sternberg Task results reveal?
Sternberg
- Hold some items before a delay
- Ask which items come before the item flashed
Results
- As number of items or WM load increases
- Accuracy decrease
- Reaction time increase
- PFC activity increase
- But we don’t know whether it’s maintainance, selection, or manipulation
How have people tried to tease apart maintainance, selection, or manipulation? What are the results
Sternberg
- Number of items is the case, but the structure is different
Results
- Structural items had more PFC activity than unstructured items
- Mean Span (Structured > Unstructured)
- Suggest configuration is represented by PFC
EEG studies/Oscillations of working memory
- Theta (4-7Hz)
- Organisation of sequentially ordered WM items
- Alpha (8-13Hz)
- Active inhibition of task-irrelevant information
- Gamma (30-200Hz)
- WM Maintenance
TAG
What is the task combining WM and EF. What are the results (And implications)
Task requiring maintance of WM load while performing congruent or incongruent responses (EF Task).
Results
- Longer RT for high WM load
- PFC activity greater for high WM load
- Greater processing in face-processing areas in high WM load
- Greater distraction and obligatory processing of irrelevant information (Faces)
- WM influence can be examined in level of FFA activity (Quantify)
Response inhibition with a WM load in drug-dependent and depressed patients.
Why?
- Inhibitory control affected by simultaneous working memory load of a craving
- Cocaine
- Depression/Anxiety
- Eating Disorders
- Thoughts are subvocally produced and rehearsed, loading on phonological loop capacity (Verbal memory load)
When there is chocolate craving, what is impaired
Significant impairment in visuospatial WM
When there is cigarette craving, what is impaired
- Significant impiarment in verbal WM that worsened with longer periods of abstinence
- Phonological loop
As WM demands increases, what predicted better performance and differentiated groups among cocaine users?
Response inhibition with WM load
- As WM load increases, inhibition performance usually worse
- Increasing DLPFC activity predicted better performance and differentiated groups as WM demands increases
What are other correlations of WM (other than EF)
Developmental type-ish
- General fluid intelligence (gF)
- Reading comprehension
- Language
- Non-verbal problems solving
Is WM related to EF. Why? Which one (WM/EF) do clinical patients show deficits in?
WM and EF are highly related (Predictive one another)
Why?
- WM is critical to goal-maintenance required for top-down EF control
- Clinical patients often show impairments in both domains
Why is low WM correlated with poor developmental type skills
Children with poor WM have failure to cope with simultaneous processing and storage demands (dual task, mental task)
fMRI research has demonstrated a relationship between working memory and intelligence, which can be best described as
- Efficiency with which DLPFC activity supports WM predicts IQ; or
- “Efficiency with which DLPFC activity supported WM mediated the relationship between gF and WM”
According to early behavioural research, does training WM improve performance?
Training WM significantly improved performance on standard WM tasks (those that have been trained), with some generalisations to other domains
What are the 2 principles relating WM and training
Training WM Task:
1.) Increase WM Capacity
(physiological change)
or
- ) Increase efficiency of using WM capacity
(via. strategy use such as chunking)
Principle 1: Increase WM capacity. What should happen
- 2 Outcomes
- ) Induce brain signatures observed in high-capacity individuals
- ) Benefits and pattern changes observed independent of specific task
What is the task to train WM
N-Back Task
Remember each item and respond to each item that occurs 2 words before
N-back task training results and caveat?
Results
- Increases in PFC activity after training
- Regions where brain activity correlated with increased WM capacity
However, they did not examine if:
- PFC increase are associated with post-training increase in WM capacity
What was argued as to how training increases WM? What might influence this benefit?
Increases efficiency (not capacity)
- Induces plasticity in intraparietal-PFC network
- Improves the control of attention
- Individual difference in dopamine may influence training benefits
- By influencing both WM performance and plasticity effects
Does WM Training improve IQ
- N-Back training shown to increase gF scores by about 4 Points
- More training = More IQ
What are some specific suggestions as to how WM training improves IQ? What do strategies include
WM-training increases strategy use. Strategies includes
- Greater use of chunking
- Automatisation of basic processes
- Shorter times on the distractor task
- More time for refreshing the memoranda
- More time for removing interfering distractor representations from WM
3 Criticisms of WM and Training Benefits
- Cost-Benefit Analysis
- Financial+Time Cost > Benefits
- Genersaibility
- No evidence of generalisation to other skills/tasks
- Sustainability
- Weak/mixed evidence after cessation of training
WM training on ADHD children in a randomized-controlled trial.
Results.
What does it suggest.
Good:
- Raters: Lower symptoms
- Parental and Teacher rating: Increase in EF performance
- WM Performance: Increase (Specific)
No Change
- Independent Raters: No change
- Lab Test: No Change
- Academic performance: No change
Suggest strong placebo effect by parents
Study: Neuroracer Descriptives and Results
N = 47, 67 years old
- Both behavioural and neural support
- Increases WM performance, supported by EEG
- Midline theta power and theta coherence improved
- Only WM performance, no evidence of far transfer
Criticism of Neuroracer’s publications.
- Most comparision are not significant but not reported
- Far transfer did not occur
- Multiple comparision not corrected
- Competing financial interest (founder of company)
- Publication Bias
- Excluded many participants in screening
Academic outcomes of WM Training in children
No outcomes.
In fact, Math scores were worse
Does Far Transfer of WM Training occur?
Why/Why not?
And what is the implication?
No.
- Placebo (Most far transfers observed is due to this)
- Premorbid cognitive ability predicts engagement in cognitively demanding actvities
- Skill acquisition rely on domain-specific information (e.g. chunking). Neural patterns observed in these people reflect change in domain-specific abilities
Implication
- Neural plasticity and skill acquisition are related but domain-specific
- Most effective way to acquire a new skill is to train that particular skill
