Control

Question 1

EXECUTIVE CONTROL MECHANISMS/EXECUTIVE FUNCTIONS

Answer 1

• brain/mind has many available specialised/domain-specific modules for categorising/analysing/language generation/calculating/action choice/rehearsing/mental rotation etc.
• BUT many aren’t automatic/constant/linked up
• must select/activate subset of processing modules then organise/link/tune then to accomplish task

Question 2

SELECT/ACTIVATION OF SINGLE TASK SET

Answer 2

• each encountered object afford many tasks
• task-set = appropriate perceptual/cognitive/motor resource organisation to carry out task
• “wilful” selection of adopted task-set according to goals/environment automatically triggering familiar task-sets (reading/emotion recognition) = to some extent

Question 3

OTHER FUNCTIONS ATTRIBUTED W/EXECUTIVE CONTROL

Answer 3

• inhibiting inappropriate actions
• updating = selecting WM info for maintenance/suppression
• managing LTM search
• monitoring performance/trouble shooting/adjusting accuracy + performance speed balance
• multi-tasking aspect coordination (ie. keeping dif info streams segregated/prioritising tasks)
• sequencing/planning multistep tasks especially where required actions = nonhabitual

Question 4

LURE OF THE CONTROL HOMUNCULUS

Answer 4

• attribution of control to unitary inner agent ie:
  BADDLEY & HITCH (1974)
• visuo-spatial sketch-pad central executive phonological buffer
  NORMAN & SHALLICE (1980)
• environment -> sensory perceptual systems -> trigger data base -> contention scheduling supervisory attentional system -> action
  GILBERT & BURGESS (2008)
• sensory info -> schemas -> response systems
• schemas supervisory system

Question 5

INVESTIGATING CONTROL PROCESSES

Answer 5

• natural history of control = obvs: IRL control failures (action errors)/pathological control failures post TBI)
• beh exps = engage control processes isolating/studying performance contribution in pps/patients ie: response conflict/task-switching/stop-signal/dual-task/multitasking exps
• we measure brain activity correlated w/control function exercise in paradigms

Question 6

EVERYDAY CONTROL ERRORS

Answer 6

• systematic error analysis = diary studies (ie. NORMAN (1981))/accident enquiries (REASON (1990))
• control error examples =
• capture errors; habitual/recently-exercised action patterns seize beh control
• cross-talk errors; failure to separate concurrent task elements (ie. concurrent writing/speaking)
• lost intentions; failure to initiate intended action when trigger conditions set in prospective memory occur

Question 7

BRAIN DAMAGE -> CONTROL PROBLEMS

Answer 7

HARLOW (1868)
- patient Gage; lost control (ie v rude) w/brain damage
LURIA
- most lost w/prefrontal cortex damage
- PFC = high beh organisation suggested initially via clinical descriptions of patients w/damage (ie. Luria)
- neuropsych testing revealed many control problems
- not always associated; dissociations = executive function fractionation

Question 8

PFC DAMAGE IMPAIREMENT EXAMPLES

Answer 8

UTILISATION BEH/MEDIAL PFC
- inability to suppress habitual action to familiar object (aka. "normal" capture errors)
PERSERVATION
- ie. Wisconsin card-sorting test
EVALUATIVE DECISION MAKING DIFFICULTY/ORBITO-FRONTAL PFC
- ie. Damasio's patient J (1999)
DISORDERED PLANNING
- ie. strategy application disorder

Question 9

STRATEGY APPLICATION DISORDER

Answer 9

SHALLICE & BURGESS’ MULTIPLE ERRANDS (1991)

• pp given money + instruction sheet (items to buy/info to find/rendezvous w/time/rules (ie. don’t go beyond line/enter only to buy)
• PFC patient (w/good Wisconsin) performance =
• disorganised performance (subtasks incomplete/ignored/repeated/inefficient)
• rules broken (crossed line/entered irrelevant shops)
• social convention violations (not paying/inappropriate)
• BUT not via motivation lack (work-rate = high)

Question 10

NO SINGLE EXECUTIVE HOMUNCULUS

Answer 10

• observed dissociations w/executive control impairments post brain damage argue against unitary central executive
• instead = distributed control mechanism network (in dif PFC parts ie. basal ganglia/parietal cortex)
• maintaining/controlling temp storage buffers = small aspect of executive control mechanisms

Question 11

CAPTURING CONTROL IN LAB

Answer 11

• situations examined where:
• task-set suppressed
• reset control parameters
• inhibit actions/thoughts/memories/emotions
• manage multiple info flows
• try isolating effects of above demands on performance/brain activity from task-specific processes/arousal/emotion effects

Question 12

STROOP’S RESPONSE CONFLICT

Answer 12

• already have colour-naming/reading (^ practiced/habitual/automatic) task-sets in brain
• we try selectively attending colour + apply naming task-set BUT can’t completely suppress reading task-set
• RT difs between 2cs = response conflict (indexes incompleteness of control)

Question 13

FLANKER EFFECT

Answer 13

GRATTON et al (1992)

• response conflict triggered via instructed task application set to irrelevant objects
• 5 letters appear; attend central; left = S; right = H
• incongruent (slow) - neutral - congruent (fast)
• found lateralised readiness potential
• attentional spotlight spread allows response activation via flankers

Question 14

COMPARING TASK SWITCHES W/REPEATS IN TASK-CUEING EXP

Answer 14

• on each trial, 1/2 tasks cues appear (letter/string; number/digit); compound stimulus follows ie. E2
• classify letter/vowel/consonant OR digit = odd/even
• stimulus interval response = 1500ms

Question 15

RESPONSE CONGRUENCE EFFECT

Answer 15

• indicates facilitation/conflict from activation of response appropriate for the other task
• other task-set is still active not completely disabled
• reduction in switch cost given time to prepare measures mental configuration for task change
• irreducible residual cost measures limits on preparation ability (inter via task-set inertia)

Question 16

BRAIN ACTIVITY ASSOCIATED W/TASK-SET RECONFIGURATION

Answer 16

ELCHLEPP, LAVRIC & MONSELL (2015)

• stimulus = word w/coloured letters
• cue specifies task:
• categorise word semantically (living/non-living)
• decide if colour pattern = symmetrical

Question 17

NEURO-IMAGING RESPONSE CONFLICT + TASK-SET PREPARATION

Answer 17

MACDONALD et al (2000)

• conflict detector = ACC (anterior cingulate cortex) activated ^ post incongruent than congruent stimuli
• task-set maintenance/stronger task-set suppression = L.DLPFC = left lateral prefrontal cortex activated via harder colour-naming prep > via word-naming prep

Question 18

IMAGING TEST-SET INERTIA W/FMRI

Answer 18

YEUNG et al (2006)

• stimulus = word on face
• classification tasks in runs of 4 (word/syllable number; face/gender)
• RT switch cost on first run trial
• localiser tasks establish word/face selective regions of activation in separate blocks (left inferior temporal gyrus/right fusiform gyrus respectively)
• switch trial related face specific area activation predicts RT cost of switching to word task; word-specific area predicts RT cost of switching to face task

Question 19

PROLONGED PROCESSES ON TASK-SWITCH TRIAL

Answer 19

ECHLEPP et al (2015)

• manipulated word frequency = effect shows in ERP from 280ms
• frequency effect onset delayed on switch trials via substantial residual residual RT switch cost fraction
• early processes prolonged on switch trials; attentional inertia?

Question 20

STOP-SIGNAL RT: RESPONSE INHIBITION MEASURE

Answer 20

• choice RT (circle/square); on some trials, tone signals “don’t respond”
• stop-signal RT (SSRT) = vary stop-signal delay to find time required to inhibit response
• fMRI = IFG (right inferior frontal gyrus)/pre-SMA/basal ganglia associated w/stopping; rTMS-IFG impairs stopping NOT going
• ADHD adults = stopping impaired BUT go RT isn’t; abnormal also in OCD/Tourette’s

Question 21

SUMMARY

Answer 21

• executive control mechanisms are:
• essential human cognition component
• observed to fail sometimes in action errors
• may be selectively impaired by brain damage
• can be captured/studied in some lab paradigms
• non-unitary
• dissociate neuropsychologically (dif PFC regions)/via fMRI dif brain region association/individual difs