Rob (Not Edited) Flashcards
What is cognitive control
Conscious internal goal take precedence over automatic processes
Three behaviors demonstrating top-down cognitive control
- Inhibitory Control
- Impulse Control
- Selective Attention
What is the neural network needed for cognitive control based on initial studies. What study did they use.
Stroop Task:
- ) Anterior Cingulate Cortex (ACC)
- ) Dorsolateral Prefrontal Cortex (DLPFC)
What is the brain areas in charge of cognitive control doing in the stroop task?
- Dorsal ACC
- Detects response conflict present in an incongruent word
- i.e. Greater level of control
- Detects response conflict present in an incongruent word
- DLPFC
- Implement top-down control over performance
- e.g. biasing visual system
- Implement top-down control over performance
How did they resolve the questions regarding how the neural network on cognitive control resolves conflict in the stroop task?
Egner and Hirsch (2005) fMRI study
- Stroop Task with congruent/incongruent face-name stimuli
- Faces are known to elicit BOLD response in FFA
- Could test whether:
- Amplified processing of face (Faces target)
- Suppressed processing of face (Face distractor)
- Both
- Could test whether:
Results and conclusion:
Face-name stroop task with fMRI
1.) When faces were target
- Higher cognitive control performance associated with increased FFA activity compared to low control trials
2.) When faces were distractor
- Control performance not associated with FFA activity
Conclusion
Better cognitive control performance associated with amplified neural representation of task-relevant information (In this case, amplified processing of faces)
When tested on functional interactions between regions associated with higher cognitive control and FFA, what did they find?
Psychophysiologic Interaction Analysis (PPI):
Only functional coupling between DLPFC and FFA increased under high control in face target condition,
but not in the face distractor condition
What are common tasks examining inhibitory control.
Why?
Go/No-Go and Stop Signal Task
- Requires participants to withhold a prepotent, or automatic, motor response
- Ideal for neuroimaging, EEG, TMS, as it allows events of interest (success/failed inhibition) to be isolated in time from on-going task-related activity
Inhibitory Control: What did fMRI find
Successful response inhibition involved:
- ) Right IFG
- ) Right parietal
- ) Dorsal ACC
(Note: fMRI only allows correlation)
Inhibitory Control: What did leision studies find
Volume of lesion damage to the right IFG exclusively, correlated with SSRT (Faster times = Better Control)
- Right IFG
Inhibitory Control: What did TMS studies find?
SSRT
- Right IFG
- TMS of middle frontal or angular gyrus had no effect
- TMS of all three sites did not significantly affect the speed or accuracy of go trial responses
- Speed of responding is important in response inhibition studies, because the faster you respond the harder it is to inhibit
Based on fMRI, leision and TMS studies on IC, what is the critical region for inhibitory control?
What is the point of running so many different methods?
Right IFG
- Combination of methods allows discrimination of the network of regions important to response inhibition
- Which can then be tested with causation using either TMS or a lesion study
Disadvantage of leision studies
Inability to specify discrete neuroanatomical regions
What is the DSM Criteria for Substance Use Disorder. What is the key thing they are looking out for?
- Larger amount or longer period than intended
- Persistent desire or unsuccessful efforts to cut down
- Relative, not absolute, loss of control.
Is cognitive function related to treatment success? Why?
How does treatment success assist with this?
Cognitive function is related to treatment success
- Ability to inhibit the immediate pursuit of pleasurable stimuli
- Development of adaptive patterns of behaviour
- Key factors in drug dependence
Treatment
- Assist directly, or
- Indirectly through greater cognitive capacity from CBT
What is the evidence that dependent drug users and gamblers have poor self control (Results and Neurological Implications)? What is unclear?
Dependent drug users and gamblers: SSRT and GNG
Behavioural
- Poorer performance on self-control tasks
Neurological
- __Significantly lower activity in PFC and ACC
Unclear
- Causal relationship between drug use and brain
- To what extent dysfunction is caused by or causes drug use
What is the evidence that drug users suffer interference from drug-related stimuli? Results?
Drug-related Emotional Stroop
Results
Active and abstinent drug users:
- Slower RTs for the drug-related words or pictures compared to neutral words or pictures
- Cocaine users suffer significant interference from cocaine related words and pictures in comparison to controls
- Both groups are distracted by evocative stimuli
How do drugs (natural or unnatural) attain salience?
- Drugs (including natural rewards) produce euphoria
- Overactivates limbic centres in the brain via dopamine release in nucleus accumbens (NAc)
- Limbic system closely tied to hippocampus
- Repeated pairing drug-induced euphoria with drug-related stimuli creates association
What is the evidence suggesting that drug users are attentionally biased towards drug stimuli
Change Blindness Task
Attentional Bias
- Heavier alcohol users were more sensitive or attentional biased to alcohol-related stimuli
- Required less latency to detect
What is attentional bias predictive of in drug-users
Predicts treatment outcomes and success (cocaine users and alcohol users)
What are evidences suggest that drug-naive children has poor control?
It was found that drug-naive children:
- Prefrontal dysfunction
- Poor cognitive control performance in drug-naïve children predicts risk for subsequent drug addiction
What kind of behavior does PFC activity in IC predict (Whelan)
PFC activity during IC task:
- Predicted binge drinking
- At age 16 using model of parameter at age 14
- Predicted relapse
- More than >89% accuracy
What is ADHD characterised by?
What are neuropsychological deficits in ADHD?
What are ADHD symptoms
ADHD
- Inattention
- Hyperactivity
- Impulsitivity
Neruopsychological Deficits
- Response inhibition
- Motor timing
Symptoms
Response inhibition
- Reactive responses + problems delaying
- Poor protection of interference
Motor
- Motor Clumsiness
Social and Emotional
- Disruptive Social Behaviour
- Emotional Dyscontrol
Improving control: Psychopharmocology.
What is the outcome variable (IC Tasks)
-
SST (Inhibitory Control) and Attentional Task
- Improved by Noradrenrgic
- Improved by MPH (Ritalin)
- MPH associated with right IFG increases during stop trials
-
Reward Learning Task
- Improved by Serotonergic
Outcome Variable: IC Task
What are the neurobiology behind MA users.
What are the 4 things it predict?
Depleted D2 receptor levels and metabolism
Level of depletion: Predicts
- Relapse Risk
- Development of Parkinsonian Symptoms
- Associated with 4x greater risk of developing Parkinson
- Associated with greater reward impulse
Can we improve control in diseases?
Cognitive enhancers have NOT generally improved treatment outcomes for psychostimulant users in RCTs, or have mixed results at best
- Modafinil
- Methylphenidate/Ritalin
Outcome: Relapse
TLDR: Improve task performance, not treatment outcome
What are recent trials demonstrating neuroenhancers improving treatment outcomes
Dexaamphetamnie
What is ADHD and Drug Addiction characterised by neurobiologically?
Low tonic levels of dopamine
What is the role of dopemine in response inhibition
Role for dopamine in response inhibition is unclear
- Either
- Transform top-down inputs into context-dependent signal; or
- Modulate between seeking stimulation and avoiding overstimulation
What disease is a good example of the complex relationship between dopemine and cognitive control
Parkinson Disease
- Associated with low inhibition and low dopamine
- No evidence that dopemine replacement therapy improves cognitive control
- Subset of PD patients who begin DRT develop impulse-compulsive behaviors
What does showing drug-related stimuli do to drug users
- Activate limbic regions associated with use of the drug
- Strength of cravings reflected in cue-related limbic activity
What does drug-related cue activation in limbic and frontal regions predict?
Magnitude of drug-related cue-induced activation of limbic and medial prefrontal regions predicts subsequent relapse
What cognitive deficits do MA users show
- Poor verbal memory
- Slowed Processing speed
- Executive function
- Disinhibition
- Selective attention
- Decision making
- Cognitive flexibility
What is the magnitude of cognitive deficits are MA users compared to cocaine users, marijuana users, AD
Significant magnitude across domains (Learning, EF, Memory)
- Higher than cocaine and marijuana
- Slightly lower/Comparable to Alzheimer.
Does behaviour (frequency, duration and quantity) of MA use predict level of cognitive impairment?
Though MA use has been associated with impairment, use behaviour does not predict.
- Individual (potentially genetic) variation in susceptibility to MA toxicity
- Older participants
- Men
- Confounded by co-morbidity (other psychiatric conditions)
D2 Levels. Which has been linked to vulnerability to addictions or protetive factors?
- Lower D2 = Vulnerable to addictions.
- High D2 = Protective factor in siblings of drug dependent individuals
What is the Inverted U-shaped curved in dopemine (Volkow). Compare low D2 and high D2
Optimal level of Dopamine stimulation to be ‘pleasant’
- Low level of d2 receptors
- Large drug-induced increases in DA result in optimal stimulation
- High levels of d2 receptors
- Large drug-induced increase pushes them to far and into the unpleasant range of the curve
What gene has been proposed to affect D2 receptors in the midbrain? What has possession of this gene been associated with?
What is associated with greater dopamine stimulation?
And what do they benefit from?
What do they predict?
Gene
- Taq1A allele. Possession of 2 copies associated with:
- Reduced D2 density
- Hypodopaminergic State
- Low dopaminergic tone
- Reduced D2 density
Why
- Positive reinforcement (euphoria) and negative reinforcement (stress reduction) associated with dopamine stimulation is linked to source of stimulation, giving it greater salience and desire
- Limbic System
- Benefits from external dopamine stimulation
- Directly (cocaine) or indirectly (risk-taking)
Predicts
- Predicts drug dependence (2-5x)
- Predicts poor responses to treatment and high relapse
What is ‘supersensitivtiy’ in Taq1A
‘Supersensitivity’:
After abstinence, Taq1A experience more powerful euphoria upon taking their previously addicted substance, making them vulnerable to relapse
What is the underlying principle of human learning. Elaborate.
Prediction error
- Difference between what expectations and outcome
- Size of difference (Prediction error) is represented in dopamine cell activity
- Greater magnitude = More likely behaviour will change to move closer to perceived ‘succesful state’
What does prediction error system aim to maximize. What else influences the system?
Reward.
- Feedback indicating an outcome much better than expected
- More likely to be learnt
- Individual differences and maturational changes in the desire to (a) seek reward or (b) avoid punishment also influence the prediction error system
Dopemine and Games: What is it sensitive to
Dopamine release is sensitive to:
- Difficulty
- Game gets harder, rewards more intermittent
- Probability
- E.g. poker machines
- Never know when you win, but win just often enough to entice
- Satiation
- Hedonic adaption is the effect that satiation has on dopamine release to intermittent rewards
People who self-report high impulse has been associated with..? What does amphetamine help with and what hypothesis was it consistent with?
Low D2.
Small amount of amphetamine led to greater D2 release.
- Consistent with hypothesis
- Individuals with low D2 have enhanced response to D2 stimulation
- Enhanced response associated with stronger subjective desire or ‘wanting’ of the drug
How do we operatinalise impulsitivity
Baratt Impulsitivity Scale
What does selective attention require
Selectively attending to stimuli in the presence of incongruent or salient stimuli requires top-down control
High sensation seekers have been associated with…
- Low reward sensitivity
- (Need high sensations to bump up)
- Poor inhibitory control
Does the limbic system pattern of activation found in alcholic extend to children?
Yes in drug-naive children of alcoholics
- More sensitive to reward
- Less sensitive to punishment
How do we operationalise impulsiveness for reward
- Delay discounting task
- Immediate reward vs Large delayed reward
How do we operationalise decision making
Gambling Task - Good decks vs bad decks
Gambling task in drug users individuals
Drug abusers showed impaired performance (bad decisions)
- Cocaine users show poorer decision making
- Less DLPFC and ACC activity
- Greater Orbitofrontal activity
What is a cool way of treating substance use disorders
Contingency management.
Provide tangible, positive, reinforcement for objective evidence of behaviour change.
What is the neuro and bio behind ADHD and drug addiction
Combination of
- High drive for reward
- Low ability to control reward impulse
- Low sensitivty to punishment
- Modulated by Dopamine (Low levels)
What is the key role of dopamine
Key: Reward Sensitvity
- Vulnerability to drugs
- Novelty-seeking
What is performance monitoring
Identification and correct differences between an intended and executed response
Neuropsychological symptoms of performance monitoring deficits
- The difference between knowing and doing
- Perseverative behaviour
- i.e. no learning
- Lack of insight
- i.e. denial
What do many clinical group show neurologically in performance monitoring?
Hypoactive ERN/ACC after mistake
- Cocaine users, SZ, AD, Alcohol, borderline personality disorder; medication-naïve adolescents with ADHD;
- However, this could be due to a number of different explanations: task is too boring, doesn’t evoke enough emotion when a mistake is made etc.
What is the exception group which shows hyperactive ERN
OCD and OCD students
Heightened error-related ACC and ERN response
What is the ERN and what does it correlate with?
- ERN in ACC (Medial Frontal Region) approx 50 to 100ms after making an error
- ERN correlates with error awareness
- Confident they made an error = Higher ERN
What is the “Rabbitt effect” and who shows it
“Rabbitt Effect”
Cautious, or slowing, of response times immediately following an error
- SZ Patients, or any group with hypoactive ACC/ERN
What is the two-factor theory of delusion. What does it explain
Explains monoethetic delusions.
- Factor 1
- Depends on where brain has damaged cortex
- Factor 2
- Each share a common dysfunction in belief evaluation
What is the one-factor theory of delusion
- Dynamic relationship between top-down and perception.
- Impaired prediction error system to update beliefs.
What are the 3 hypotheses on what ERN represents?
- Emotional impact of an error #1
- Response conflict #2
- Two competing responses
- Reward less than expected #3
- Relative outcome
The conflict monitoring theory of dorsal anterior cingulate cortex (dACC) function argues that it responds to the response conflict inherent to many executive function tasks, such conflict arises from what
Competition between two competing responses, which are typically congruent and incongruent to the task requirements
What is the evidence that ERN represent conflict monitoring (#2)
What is the caveat?
2 Evidence:
- ACC activity during error correlates with slowing of response speed on the following trial
- Greater ACC during an error thought to reflect response conflict in trials
Caveat
- Separating the “response” from “accuracy feedback” results in greater ACC activity for the “feedback“ compared to “response”
What is the neurobiology behind ERN and the proposed role of ACC based on #2
#2
- ERN in ACC
- Decrease dopamine in Midbrain (Basil Ganglia)
- Correct response
- Increase dopamine in Midbrain (Basil Ganglia)
Proposed Role of ACC
Trasmit value of response to regions critical for behaviour
(.e.g DLPFC for inhibition; hippocampus for learning)
What is the underlying principle underlying human behaviour and how does it relate to prediction errors?
Prediction error
- Greater magnitude of prediction error
- Greater dopamine cell activity
- Likely behaviour will be ‘successful’
The reward prediction model of error:
How does ERN represent outcome relative to expectation (#3)
Reward prediction model of error #3
ACC activity or ERN reflects outcome relative to prediction
Evidence: Gambling Task
ERN influenced more by relative loss or gain, than whether a participants was correct or incorrect
- Gain + Correct / Loss + Error was greater than
- Gain + Error / Loss + Correct
How does ACC lesion relate to prediction error based on animal studies?
What does it suggest?
ACC Lesion in Monkeys
- No impairment in performance immediately after an error
- Intact learning from immediate feedback
- Unable to sustain rewarded responses
- Impaired ability to integrate feedback over time
Suggests ACC integrates value of outcome information
Do PD Patients learn better from Reward or Punishment (Experiment)
Patients off-medication (Low Dopemine)
- Better learning from punishment than reward
Patients on-medication (High Dopemine):
- Better learning from reward than punishment
[Note: Uncommon weird pattern in PD as usually low dopamine means greater sensitivity to seek reward]
Taq1A and learning patterns: Rewards vs punishment
- Low D2 receptors (Taq1A) learn better from reward
- But ‘Typical’ pattern (Normal D2) learn better from negative feedback/punishment
How does ACC represent perceived and unperceived errors? Evidence from antisaccade task.
ERN represents both perceived and unperceived errors similarly (Unconscious detection)
What is Error Awareness Task
Simiar to stroop task
Incongruent: Repeat words or correct colour words, leading to many unperceived errors
What did the Error Awareness Task reveal?
- ACC activity was necessary, but not sufficient, for awareness
- ERN was similar, does not vary in whether participants were aware
- ACC is important for awareness, but does not determine if we are aware
- Insula and parietal activity predicted awareness.
(GSR reveals that they truly were unaware, not just forgetting to tell the experimenter)
What brain areas in drug-abusers/others are associated with poor awareness (independent of task perforamance)
Cocaine, Cannibis, ADHD, SZ, Traumatic Brain Injury, AD
Reduced activity in both ACC and insula are associated with poor error awareness, independent of task performance
- Hypoactive ERN
- Poor insight into their own symptoms
- Poorer inhibitory control performance
- Poorer awareness of inhibitory failures
- Only in repeated trial errors
- Conscious error perception in congruent trials comparable to controls
In cocaine-dependent users, what is the hypoactive ERN associated with and what did it predict?
Hypoactive ERN
- Associated with reduced insight into effects of drug use
- Predicted likelihood of relapse and extent of cocaine use following relapse
What does insula do?
- Involved in all subjective feelings
- Awareness/ Interoception, of afferent representations of the feelings from the body
Why do drug addicts not seek help
It is partly due to lower awareness = don’t realize need for help
What happened to smokers when the insula is damaged. Why
Likely to quit.
Insula critical to awareness of cravings > lost cravings
How does the insula and ACC work together
- Insula
- Limbic sensory
- Site of awareness on basis of afferent representations
- ACC
- Motor cortices
- Initiation of behaviour.
Why does Methylphenidate influence the magnitude of the error-related negativity?
Methylphenidate influences prefrontal dopamine release
Can we use drugs to enhance ERN (specifically ERN only). What is the underpinning physiological changes
Yes.
- Single dose of MPH can improve error awareness without much change in response speed, accuracy, or inhibitory control
- Underpinned by physiological changes in ACC (Or parietal in sustained attention)
Neural mechanisms of learning
Strengthening of synapses.
Learning must be associative (emotions, motor planning)
How to maintain durable and flexible encoding
- ) Meaningful encoding upon broader framework
- ) Retrieval Practice
What is the relationship between sensitivty to reward and dopamine
- Less D2 = Increased sensitivty to reward
- Less D2 = Decreased senstiivty to punishment
What is the monetary incentive GNG task
Adding a punishment factor into GNG task
Results of monetary GNG task in drug-abusers vs control (Include Brain Parts)
Punishment manipulation
Significantly improved performance for both groups
However,
- Controls more sensitive to punishment
- Greater post-error slowing
- Insula: r = 0.40; dACC: r = 0.37
- CD shows dimished response to punishment
- Less post-error slowing
- Hypoactvity in dACC and insula
- Insula: r = 0.04 ; dACC: r = -.05
Why was paired-associative learning task developed?
Examine confound: Do gambllers perform badly because of failed learning or risk-taking?
Paired-associative learning in cannabis users - Behavioural and neural results
- Reduced ability to correct
- Reduced ACC and hippocampus
- ACC trasmit value to hippocampus to learn
What is the outcome measure of paired-association learning task
Number of repeated errors
(Number repeats down the sequence. See whether they learn)
What were the results of the associative learning task - Brain Parts implicated
Mistake Learning/Corrected
ACC and hippocampus (learning)
ACC trasmit value to hippocampus to learn
What were the results of the associative learning task when punishment is involved - Neurological results
(What is the implication)
- ACC not modulated by punishment/size of penalty
- ACC detects how it should influence future behaviour
- Insula modulated by punishment/size of penalty
- Insula learn from adverse outcomes, and if no insula, we don’t learn from severity of outcome.
What is ACC related to in learning outcomes
ACC activity reflects the extent to current outcome should dictate future actions. It is NOT modulated by punishment.
- Rmb: leisioned ACC in monkeys showed only last outcome affected and they are unable to integrate feedback over time
ACC and Insula: Summary
ACC
- Detect error (conscious and unconscious)
- Both perceived and unperceived errors.
- Not modulated by severity of punishment.
- Determines how current outcomes should predict future behaviour by transmitting information to other relevant regions
Insula
- Afferent representations
- Detect error (conscious)
- Perceived erorrs
- Modulated by severity of punishment
Both needed for learning
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