PFC

Question 1

PFC

Answer 1

Must be doing something imp to distinguish us from other animals

see notes

Shows development trajectory of brain devel between 5-20

Scale shows density of gray matter across brain

Thins over whole brain

Biggest changes in red region – PFC

see notes

Question 2

connections of the frontal cortex

Answer 2

Connected to most regions – role in behav

see notes

Question 3

Phineas Gage

Answer 3

“The equilibrium or balance…between his intellectual faculties and animal propensities, seems to have been destroyed.

He is fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, at times obstinate, yet capricious and vacillating, devising many plans of future operations, which are no sooner arranged than they are abandoned in turn for others appearing more feasible. …

In this regard his mind was radically changed, so decidedly that his friends and acquaintances said he was “no longer Gage”

Question 4

Wisconsin Card Sorting Task

Answer 4

Set shifting task

Set = approach to a problem

Given single card and must choose which of 4 decks to place card on

Have to learn rule governing which deck should be placed on and continue to place diff cards on same deck according to correct rule

Rule could be based on colour, shape, no. of shapes etc

Patients must use trial and error to find correct rule

After 10 consecutive correct responses, rule changed and patient must discover new rule

Task-set switching/shifting

Must acquire ‘set’ for task perf = rule/set of rules

Set can switch repeatedly throughout task

see notes

Question 5

errors on WCST pre- and post-surgery - Milner (1963)

Answer 5

Deficit of inhib (inhib previously relevant ‘set’ and responding appropriately using currently relevant set)

Those w/ frontal lobe injuries showed disproportionate impairment on task

Perseverated – after rule changed, tended to carry on responding according to same rule

Conclusion that PFC doing something related to inhibition – enabling flexible behav by inhibiting (suppressing) previously relevant, but no longer relevant, responses

see notes

Question 6

Shallice and Burgess

Answer 6

Patients with frontal lesions often perform normally on ‘frontal’ tasks such as Wisconsin Card Sorting Task

Still fail at simple tasks such as going to shops
o Disconnect
o Deficit may be more complex than previously thought

Question 7

deficits of patients w/ frontal lobe lesions on standard neuropsych tasks - Shallice and Burgess (1991)

Answer 7

Patients w/ frontal lobe lesions not v. impaired on tasks that measure frontal exec functions

E.g. Stroop task (attentional interference), Tower of London task (planning), even modified WCST

see notes

Question 8

six elements task - Shallice and Burgess (1991)

Answer 8

Limited total time (e.g. 10 mins)

6 diff tasks to work on, such as picture naming, arithmetic, visual cancellation task

Goal is to work on all 6, and hopefully complete all 6 in 10 mins

Score based on no. tasks attempted, and score penalties given for rule infractions/not spending equal amount of time on each task

Question 9

deficits of patients w/ frontal lobe lesions on the six elements task

Answer 9

“The problem arose from an inability to reactivate after a delay previously generated intentions when they are not directly signalled by the stimulus situation….

These processes lie in the domain of the creation and maintenance of goals and intentions, of their realization at appropriate times (prospective memory) and of planning…where a task cannot be adequately carried out through the application of well-learned action or thought routines alone, it requires the use of a Supervisory System, which is anteriorly located in the cortex”

Only attempted 2/3 of tasks and spent large amount of time on each sub-tasks

Deficits due to breakdown in unitary supervisory system, located in PFC

Worse on tasks that mirror real-life

see notes

Question 10

the SAS model - Norman and Shallice (1980)

Answer 10

Supervisory Attentional System

Explains how behav can operate in non-routine situ’s – where well learned behav sequences not sufficient

WCST could been seen to be model of type of behav – patient leanrs rule governing responding but then has to re-learn rule repeatedly

see notes

Question 11

problems with the SAS

Answer 11

‘Homunculus’ criticism

Who controls controller?
o Problem then is how second system is controlled

Explains what is controlled but not how control exercised
o Black box without any attempt to explain how it carries out its function
 Very influential in psych
 Control system in PFC used as explanation in neuropsychiatric disorders
 Addiction/ADHD/Sz can be partly explained by deficit in PFC control systems
 All it does is re-describe behav symptoms using diff (technical) words

Question 12

fractionating exec function - Monsell and Driver (2000); Verbruggen et al. (2014)

Answer 12

“Dissolve, deconstruct/fractionate executive! Let a hundred idiots flourish”
o Identify basic cog processes underlying cog (behav data – FA)
 Can produce coord, goal-directed behav through coord functioning
 Identify underlying common and distinct variables that diff tasks rely on further idea that should be possible to identify diff regions of PFC that are responsible for controlling diff cog processes, through neuropsych and neuroimaging
o Identify diff brain regions underlying different cog control processes (neuropsych/neuroimaging)
o Fractionate SAS into many component processes

Question 13

subdivisions of the PFC

Answer 13

Some broad agreement

see notes

Question 14

how can we fractionate exec function at the behav level? - Miyake et al. (2000)

Answer 14

Gave healthy subjects variety of tasks:
o E.g. task switching – subjects have to perf 2 tasks – odd/even or vowel/consonant – depending on location of letter/numbers
o Slower in switch trials than are in repeat trials on task

Question 15

FA of exec function - Miyake et al. (2000)

Answer 15

3 distinct, latent variables that accounted for perf diffs on 9 tasks

Variables (/factors) shown in central part
o Shifting = shifting between task sets
o Updating = updating contents of WM
o Inhib = inhib prepotent responses

Influential model – used as template for understanding how exec functions can be fractionated

Idea that any complex exec task can be accomplished by drawing on (mixture of) 3 functions

Real test is whether can map these diff functions onto diff brain regions

see notes

Question 16

is there a dysexecutive syndrome? - Stuss and Alexander (2007)

Answer 16

“Our goal was to determine whether all focal frontal lesions produced a similar impairment in cognitive supervisory control or whether lesions in different regions produced specific impairments that might or might not appear on a task depending upon the particular demands of the task.”

Tested frontal lobe patients (n = 40) on range neuropsych tasks inc. classic frontal tasks (WCST, Stroop), language and memory tests requiring exec functions and attentional tests

Brain lesions mapped out and location of brain damage defined by registration to standard anatomical template

Question 17

neuropsych ev - Stuss (2007)

Answer 17

Right lateral PFC
o Monitoring
o Process of checking task over time for ‘quality control’ and adjustment of behav
o Miyake’s “updating”

Left lateral PFC
o Task setting
o Ability to set stim-response r’ship
o ‘Shifting”

Left medial PFC
o Energising
o Process of initiation and sustaining of any response

Where is inhib?
o Stuss suggests it may not exist at psych level/not necessary component to explain perf on tasks used

see notes

Question 18

medial PFC - the view from neuroimaging - Carter et al. (1998)

Answer 18

Stuss = ‘energising’

ACC as “error detection” module?

Asked healthy subjects to perf ‘AX-CPT’ task (continuous perf task) in MRI scanner

See 2 letters on each trial, one after other

First can be A/B and second can be X/Y

Press button when see X but only when preceded by A

Leads to high error rates because on some trials see A which primes them to make response, but then see Y – press accidentally

Measure brain activation during error and correct trials and found increased activation in ACC for errors relative to correct trials

see notes

Question 19

medial PFC - the view from neuroimaging - Bush et al. (1998)

Answer 19

fMRI - counting Stroop

say how many words were on screen on each trial

Interference (word 2 when 4 words on screen) v neutral trials (dog)

ACC activation higher in interference than neutral trials even when subject responded correctly

ACC involved in conflict detection

Tasks that require resolution of conflicts between competing info streams by sensory and/ response selection

Results inconsistent with previous study as show ACC activation not simply associated with errors

Suggests error-related activation occurs because of detection of conflict between competing info streams

On error trials, conflict arises due to mismatch between subject’s expectation that they got trial correct, and incorrect feedback they actually receive

see notes

Question 20

role of the medial PFC in cog control

Answer 20

Neuroimaging inconsistent with lesion ev
o Bush/Carter – ACC activation related to conflict monitoring
o Stuss – ‘energising’ behav

Possible role for ACC in evaluating effort associated with a choice
o Grinband et al. (2008) – Stroop task
 ACC activation linked to time-on-task – greater activation for slow RTs than fast even on congruent trials
 Potential resolution to inconsistency
 ACC sensitive to amount of effort involved in task perf

see notes

Question 21

left lateral PFC - the view from neuroimaging - Kim et al. (2012)

Answer 21

Results of meta-analysis of 36 task switching studies
o Compared switch trials v no switch trials
o Bilateral pattern of activation, distributed across frontal and parietal regions – greater activation for switch trials than non-switch trials
o DLPFC preferentially left lateralised
o Some convergence w/ neuropsych ev but suggests more distributed network involved

Question 22

further neuroimaging evidence suggesting a role for parietal cortex in task-switching – decoding of task rules from patterns of activation in lateral PFC and parietal cortex - Bode et al. (2009)

Answer 22

see notes

Analysed fRMI data with MVPA method – decoding cog states from patters of activation

Gave subject task-switching task in which subjects saw cue (letter A/B), followed by 1 of 2 coloured patterns

If cue was A, subject had to make left button press response for pattern 1 and right button press response for 2

If cue B, had to flip stim-response association and make right button press for 1 and left for 2

Used pattern classifier

Found task rules could be decoded from parietal and PFC

Line graphs - bin 1 = cue presentation, bin 3 = target presentation, bin 5 = response)

Top graph shows decoding perf for region in parietal cortex (left intraparietal sulcus)

Bottom graphs show decoding perf for regions in PFC

Successful decoding of task earliest in parietal region (before target presented) whereas task could only be decoded later in trial from PFC activation (after target presentation)

Question 23

left lateral PFC - view from neuroimaging

Answer 23

Partial support for the Stuss idea that left lateral PFC involved in task setting/switching

Neuroimaging reveals more distributed system inc. right lateral PFC and inferior parietal cortex

Possibly key role for parietal cortex

Question 24

right lateral PFC - ev from neuropsych

Answer 24

Stuss: monitoring – process of checking the task over time for ‘quality control’ and adjustment of behav

Aron et al. (2003) demo’d imp of right inferior frontal cortex for response inhib

Gave Ps w/ diff brain lesions Stop Signal RT task in which had to respond whether arrow was pointing to left/right but sometimes had to withhold response when heard loud beep

Found perf strongly related to size of lesion in right inferior frontal gyrus – pos correlation between Stop Signal RT (measure of how good subject is at inhib response) and lesion size in region – bigger lesion, worse at inhib

see notes

Question 25

right lateral PFC - ev from neuroimaging

Answer 25

Imaging studies supported findings, showing increased activation in right inferior frontal cortex during response inhib

see notes

Many studies put healthy people in scanner and given them go/no-go tasks in which subject simply has to press key when see certain letters and withhold responding when see diff letter

Activation in right inferior frontal cortex higher for no-go trials than for go, suggesting specific role in region in inhib prepotent response

Question 26

right lateral PFC - ev from neuroimaging - Hampshire et al. (2010)

Answer 26

More recent research suggests this may be due to an attentional role for the right inferior frontal cortex

In go/no-go tasks and stop-signal tasks, subject must monitor for occurrence of ‘target’ stim that indicates should withhold response

Strong attentional component, requiring target detection

Possible that activation in inferior frontal cortex during tasks actually reflects more basic target detection processes rather than response inhib

Gave subjects v. simple task in which required to monitor for occasional targets and found increased activation in right inferior frontal gyrus (and less extent left) when detected target

More basic attentional role

see notes

Question 27

convergence of ev

Answer 27

Some agreement between behav, neuropsych and neuroimaging ev for how to fractionate PFC

Also disagreement:
o Functions carried out by regions not v. precisely specified – disagreement about what specific regions ‘do’ e.g. right inferior frontal cortex
o Neuroimaging generally implicates wider networks of regions other than just PFC
o Even existence of certain exec functions (e.g. inhib) point of debate

Question 28

methodological considerations may partially account for lack of convergence

Answer 28

Neuroimaging methods show regions generally involved in task perf, not necessarily those necessary for task perf

Neuropsych reveals regions that are necessary for task perf but cannot reveal info about networks of brain regions

Is it possible to fractionate PFC?

Question 29

an alternative perspective from neuroimaging – frontoparietal cortex as a ‘multiple demand’ network - Duncan and Owen (2000)

Answer 29

Meta-analysis of neuroimaging studies of exec function, in which plotted activations associated w/ multiple diff processes, e.g. response conflict, task novelty, on single brain

Rather than there being separate regions of PFC dedicated to diff processes, diff processes all activated similar regions

No clear separation between diff processes – more like there was network of regions, encompassing regions in lateral PFC, anterior insula, medial PFC and inferior parietal cortex, that all showed increased activation when Ps did something cog difficult

Called frontoparietal ‘multiple demand’ network

see notes

Question 30

what does the ‘multiple demand’ network do?

Answer 30

Construction of ‘attentional episodes’

“Neurons have highly dynamic response properties, adapting to code the specific information and events within the current attentional focus”

“With the transition between one episode and the next, neural coalitions for one kind of information processing dissolve and coalitions for the next episode form, producing a system in constant flux.”

Adaptive coding – PFC neurons adapting responses depending on task demands

Question 31

fMRI ev for coding of more abstract info about task rules in frontoparietal cortex (Woolgar et al., 2011)

Answer 31

Ps learned diff rules governing mappings between stim and responses

When saw blue screen had to remember particular mapping between locations and button presses etc.

see notes

Used multivoxel pattern analysis to see which brain areas encoded diff info about task such as rules, colours and responses

Found that although frontal and parietal regions did encode info about position of stim, colours and responses, regions showed strongest coding of rules

Results demo that primary role of PFC in this kind task is encoding info about quite abstract aspects of task perf such as rules governing stim-response mappings

Could be claimed that regions not simply directing attention to specific stim in WM but are perf more complex function

see notes

Question 32

the gateway hyp of BA10

Answer 32

Region at front of PFC

Key distinction between stim-oriented (SO) and stim-independent (SI) attending

SO – behav required to focus on current sensory input

SI – mental processing that accompanies self-generated thought

Hypothesised to play a v. high level, abstract role in cog control

One theory says it perfs gating function, allowing us to act according to either internal goals/external stim

Idea that there are 2 gates, one that allows sensory input and one that allows output (via effector systems – e.g. muscles)

When both gates in position B, organism in SO mode, fully focused on interacting with external world

When both in A, organism in SI mode, fully focused on internal thought processes

see notes

Question 33

neuropsych ev for gateway hyp of BA10

Answer 33

Patients with lesions to BA10 have deficits in multitasking on the 6 elements task (Burgess et al., 2000)

Pattern suggests a deficit in prospective memory – difficulty disengaging from externally driven behav to switch to an internal, goal-driven mode

Question 34

role of frontopolar cortex (BA10) in cog control - neuroimaging ev - Gilbert eet al. (2005)

Answer 34

Gave subjects 3 tasks, all of which required switching between SO and SI processing modes

In task 1, in SO version a clock hand moved around clockwise once per s and subject pressed when passed red mark
o SO as responding fully based on properties of stim in external world

In SI version a clock hand moved anticlockwise once per 300ms and subjects had to maintain same rate of pressing as before (1 press per s)
o Responding based on subjects own internal mental processing (sense of timing)

Task 2: SO: navigate around edge of shape using button presses

SI: imagine shape and continue to navigate around it

Task 3: SO: classified letters as composed of straight lines, curves/combo of 2

SI: subjects continued classifying letters in alphabetical order from last letter visually presented on screen

see notes

Double dissociation between lateral and medial parts of BA10

Across all 3 tasks, medial BA10 showed stronger activation for external than internal processing

Lateral BA10 shows greater activation when subjects switched between internal and external types of processing

Interp is that BA10 acts as switch between internal and external (SI and SO modes of processing)

If true, would partially help solve key problem in cog neuroscience, which is how to tell from patterns of brain activity when someone attending to external stim and when attending to internal stim (e.g. contents of WM)

Often v. similar patterns of activation observed for 2 types processing

Makes sense if assume initial switch determines focus of attention – focus of attention (internal/external) not determined by activation of diff brain regions, but by operation of switch that occurs prior to processing taking place

see notes

Question 35

abnormal activation in BA10 in never-medicated patients w/ Sz - McDonald et al. (2005)

Answer 35

see notes

Patients with Sz have abnormal activation in BA10 during perf of simple contextual processing task requiring subjects to identify targets (A followed by X) amongst nontargets (AY, BX, BY)

Could be argued that hallucinations and delusions experienced by patients due to difficulty distinguishing whether perceptions ‘real’ (in sense of arising from external world) or imaginary (in sense of being internally generated – e.g. voices in the head)

Deficient ‘gateway’ between SO and SI processing explains source of problem

Question 36

OFC

Answer 36

see notes

Question 37

role of OFC in cog control

Answer 37

Ps presented with 4 virtual decks of cards on computer screen

Told that each time choose card will gain some money

Every so often, however, choosing card causes them to lose money

Goal is to win as much money as poss

Every card drawn will earn P reward

Occasionally, card will also have penalty

Decks differ in no. of trials over which losses distributed

Some decks are “bad decks” and other decks “good decks” because some lead to losses over long run and others lead to gains

see notes

Question 38

“Patients fail to activate biasing signals that serve as value markers in the distinction between choices with good and bad future outcomes” – role of the OFC in value-based decision making - Bechara et al. (1994, 6)

Answer 38

see notes

Normal controls generally learned to avoid risky decks and choose decks that would give overall profit

Patients with lesions to occipital, temporal and dorsolateral PFC regions showed equiv perf, preferring advantageous decks

Patients w/ OFC lesions showed overall pref for risky decks, resulting in overall loss of money – unable to learn about response-reward contingencies

Bechara et al. (1996) also tested SCR and OFC lesion patients’ perf task

SCRs during reward and punishment roughly equiv in patients and controls

Anticipatory SCRs (measured between choice of deck and receipt of reward/punishment) greatly reduced in patients with OFC lesions

Question 39

Somatic Marker Hyp (Damasio)

Answer 39

Emotional info, in form of phys arousal, needed to guide decision making

Somatic markers are bodily reactions to emotional stim

OFC supports learning of associations between somatic markers and complex situs

OFC can then use info to assess likely outcomes of behav choices

Question 40

role of OFC in reversal learning - Fellows and Farah (2003)

Answer 40

see notes

OFC represents “specialised neural circuitry for rapidly unlearning or suppressing the influence of an established stimulus-reinforcement association”

Reversal learning task, have to learn which card predicts reward and then contingencies shifted

Inc. patients w/ DLPFC and VM (OF) lesions

FLPFC unimpaired

OFC had specific deficit at reversal stage

Could learn initial response contingencies but had problems learning new contingency

Argued OFC necessary not for learning about stim-reward contingencies but for unlearning of established associations

Question 41

role of OFC in probabilistic reversal learning - neuroimaging ev - O’Doherty et al. (2001)

Answer 41

see notes

Large brain area may be divided according to diff functions

fMRI study, Ps perf probabilistic reversal learning task in which they were rewarded for choosing one reward and punished for choosing other

Once learned, contingencies changed and had to learn to respond to other stim

Found dissociable regions of OFC responded preferentially to rewards and punishments – medial OFC showed stronger response to reward

Lateral OFC showed stronger response during punishment phase just before reversal

Suggests diff regions in OFC respond to diff types of outcome – medial OFC = reward

Lateral OFC = punishment

Question 42

OFC and counterfactual thinking - neuropsych ev - Camille et al. (2004)

Answer 42

see notes

Ps choose one of 2 wheels w/ diff chances of winning

Either got partial feedback, where found out what they won and also know what possibilities were if chose other wheel, but don’t actually know what they would have won if chosen other wheel

Or got full feedback where found what they won and also what would have won if chosen other option

Asked Ps to rate level of satisfaction w/ outcome

In normal healthy subjects, show higher ratings of satisfaction when win compared to lose, but also show higher ratings of satisfaction when found would have won less/lost more if chosen other wheel

Show lower ratings when find out would have won more/lost less if chosen other wheel

OFC patients didn’t show pattern of counterfactual thinking – didn’t modulate ratings according to whether other wheel would have been win/lose

Suggests key role for OFC being able to experience consequences of winning and losing, but more imp to integrate info from diff sources of outcome

Question 43

OFC and counterfactual thinking - neuropsych ev - Coricelli et al. (2005)

Answer 43

OFC activation greater when non-obtained outcome is loss, only when complete feedback given

Key role for OFC in representing heightened emotional experience associated with avoiding loss

Phys response associated with loss avoidance (‘somatic marker’) interp by OFC and used to guide future responding

see notes

Question 44

role of OFC in cog control

Answer 44

Fac effects decision making based on knowledge of value of diff actions
o Retrieving value of goals that are outcome of decision making process
o Establishing relative preference ranking of goals
o Sending signals to other brain regions (parietal, motor cortex) to compute action values and guide responding

Question 45

corticostriatal loops

Answer 45

see notes

PFC strongly connected to diff brain regions

Some of strongest connections occur between regions in PFC and basal ganglia (/striatum) which is collection of old, subcortical structures inc. caudate, putamen, globus pallidus and ventral striatum

Loops occur in parallel, w/ diff loops connecting diff PFC regions and hypothesised to play diff roles – e.g. reward processing loop that connects ventral striatum to OFC and exec control loop that connects DLPFC to dorsal striatum

Question 46

role for the basal ganglia in cog control: ev from PD

Answer 46

gradual loss of dopamine neurons in striatum (basal ganglia)

Originally thought to be purely motor disorder
o Bradykinesia (slowed movement)
o Akinesia (impairment of voluntary movement)
o Tremor
o Studies in 1980s/90s found deficits in exec control functions
o Planning, WM, attentional set-shifting (WCST), Stroop

Motor and cog deficits have similar features
o Loss of flex in movement and thought
o Points to shared evolutionary origin for motor and cog systems

Question 47

impaired task-set shifting in PD - Cools et al. (2001)

Answer 47

see notes

Gave PD patients task set shifting task, in which they were required to either name letter/number on each trial depending on colour of background screen

In crosstalk condition, both numbers and letters presented together, and patient had to focus on relevant stim and ignore irrelevant

In non-crosstalk, no./letter presented on own

PD patients sig impaired relative to health controls on switch trials (when required to switch between naming letters and naming numbers) but only in crosstalk condition

PD patients have deficit in task set shifting, esp. under conditions of attentional distraction

Question 48

effects of DBS of subthalamic nucleus STN) and globes pallid us (GPi) on exec function in PD

Answer 48

Sig differential change of perseverative errors on WCST, which were reduced for STN group but increased for Gpi group – black bars = stim on, white bars = stim off

Stim resulted in greater improvement on TMT B and sig greater reduction of TMT B-A diff score on test for STN than GPi group

Change in X2 measure of RNG indicative of greater randomness of response for STN but not GPi group

Sig diff change of perseverative errors on WCST, which were reduced for STN group but increased for GPi group

see notes

Question 49

dopamine - more than just reward?

Answer 49

Brozoski (1979) – dopamine depletion in PFC of monkeys causes deficit in spatial WM nearly as severe as complete removal

Parkinson’s studies – dopamine in striatum also plays imp role in exec function

Indirect effects of striatal dopamine cell loss on PFC function via Corticostriatal loops

Question 50

effects of methylphenidate (‘Ritalin’) on brain activation during reversal learning - Dodds (2008)

Answer 50

see notes

Methylphenidate is dopamine reuptake inhibitor, which means that after dopamine released into synapse, prevents re-absorption, leading to overall increase in extra-cellular dopamine levels

Healthy subjects given reversal learning task in MRI scanner

On each trial, subjects presented w/ 2 abstract visual patterns

Using trial-and-error feedback, Ps must discover which of 2 patterns correct

Feedback presented as soon as P chosen

After several correct trials, contingencies switch and must select other pattern

Only region that showed modulation by methylphenidate when P switched response was putamen (part of striatum)

Results show key role for striatal dopamine in mediating cog flexibility

see notes

Question 51

Effects of bromocriptine (dopamine D2 receptor agonist) on fronto-striatal connectivity during task switching - Stelzel et al. (2013)

Answer 51

see notes

Task switching paradigm where Ps had to perf one of 2 tasks – either decide whether no. was odd/even/ decide whether no. >/< 5 – depending on shape around number

Bromocriptine modulated activation in striatum during switch trials

Bromocriptine modulated frontostriatal connectivity during switch trials

Therefore dopamine plays key role in cog flex and achieves function by modulating functional connections between striatum and PFC

see notes

Question 52

Effects of bromocriptine (dopamine D2 receptor agonist) on fronto-striatal connectivity during task switching - Van Schouwenberg et al. (2010)

Answer 52

Gating role for basal ganglia in cognition
o Flex updating of current goal states (represented by coalitions of neurons) into PFC
o Representations stable while subject focused on current task/goal
o When reward contingencies change/new info available, requiring switch in responding, dopamine signalling in basal ganglia prevents responding to previously relevant stim and allows establishment of new PFC representation, enabling diff stim to gain control of responding

Question 53

How can we fractionate executive function - Morris and Jones (1990)

Answer 53

letter memory task

Letter memory task that requires subject to remember letters but also update the letters in memory

Question 54

How can we fractionate executive function - Logan (1994)

Answer 54

Stop-signal reaction time task (Logan, 1994)

Required Ps to withhold prepotent responses

Respond as fast as can to direction of arrow but withhold responding if hear loud beep after arrow presented

Given 9 tasks in total measuring variety diff exec functions