Lecture 10 - The Executive Brain

Question 1

What is executive function?

Answer 1

Control processes that enable an individual to optimise performance, requiring coordination of basic cognitive processes - CONTROLLED BEHAVIOUR

Question 2

What domain is linked to executive functioning?

Answer 2

Not tied to a specific domain (such as memory or language) - meta-cognitive, supervisory / controlling role

Question 3

What do disorders of executive functioning cause?

Answer 3

Difficulty in decision making, organising, planning and multi-tasking etc.

Question 4

Bottom-up processes of decisions

Answer 4

Arise out of an interaction of environmental influences

Question 5

Top down processes of decisions

Answer 5

Influences related to the motivation and goals of the person

Question 6

How many cortical surfaces does the prefrontal cortex have?

Answer 6

3 - lateral, medial and orbital

Question 7

Where does the lateral prefrontal cortex lie?

Answer 7

Anterior to the premotor areas, closest to the skull

Question 8

Where does the medial prefrontal cortex lie?

Answer 8

Between the two hemispheres and to the front of the corpus callosum and anterior cingulate cortex

Question 9

Where does the orbital prefrontal cortex lie?

Answer 9

Functionally and anatomically related to the ventral part of the medial surface - ventromedial prefrontal cortex

Question 10

Role of the anterior cingulate cortex

Answer 10

Monitoring in situations of response conflict and error detection.
Emotions
Pain
Executive functions

Question 11

Phineas Gage 1848

Answer 11

Non fatal traumatic brain injury - damage in left orbitofrontal / ventromedial region and left anterior region = impaired impulse decision making, planning and social regulation of behaviour. Poor decisions and planning

Question 12

What is problem solving?

Answer 12

Related to generalised measures of intelligence

Question 13

What is task setting?

Answer 13

When presented with a goal and starting point, then coming up with a solution.

Question 14

Which brain area lesions lead to poor task setting and problem solving?

Answer 14

Prefrontal cortex

Question 15

What is the Tower of London task - Shallice, 1982

Answer 15

Beads moved from one position to a specific end point. Patients with unilateral prefrontal cortex lesions (especially left anterior) = poor performance- take significantly more moves (trial and error instead of PLANNING)

Question 16

Cognitive estimates tests - Shallice & Evans, 1978

Answer 16

‘How many brushings from a tube of toothpaste’ - those with damage to prefrontal cortex do worse

Question 17

what are FAS tests - Miller, 1984

Answer 17

PPTs asked to produce as many words starting with the letters F, A or S
Damage to left frontal dorsolateral cortex = particularly bad at this task

Question 18

What lesions impair ability at Tower of London task

Answer 18

Left anterior lesions - impairment in generating, selecting and remembering moves

Question 19

what lesions impair FAS tests

Answer 19

Left dorsolateral - poorer letter fluency, impairment in generating new strategies and selecting between alternatives / avoiding repeated responses

Question 20

WHAT is the STROOP TEST

Answer 20

Response interference from naming the ink color of a written color name (e.g., the word BLUE is printed in red ink and participants are asked to say the ink color, i.e., “red”).

Question 21

what brain areas are involved in the stroop test

Answer 21

False positives - lesions in ventrolateral PFC
Lesions in right superior medial region, anterior cingulate cortex, pre-supplementary motor area and dorsolateral areas = SLOW REACTION TIMES, DECREASED CORRECT RESPONSES

Question 22

What is the GO/NO GO TEST

Answer 22

response to certain stimuli, inhibit response for another stimuli
e.g) stage 1 : A = go, B,C,D = no-go
stage 2 : B,C,D = go, A = no-go
- PPT have become habituated to original stage

Question 23

Which brain areas are involved in the GO/NO GO TEST

Answer 23

Superior medial frontal lobe - response inhibition. Lesions in this area are slowest at the task.
Lesions in this area had more false alarms - reacting to impulsivity. Reaction time decreases after making a false alarm in stage 2

Question 24

Task switching - Wisconsin card sorting test

Answer 24

Match a card to 1 out of 4 reference cards
Symbols on the card vary in shape, number, colour
If matched incorrectly - switch trial (causes reaction time to decrease)

Question 25

What is the switch cost?

Answer 25

When there is a big change in reaction time between no-switch and switch trials. A slowing of response time due to discarding a previous schema and having to set up a new one.

Question 26

Meuter & Allport, 1999 bilingual study

Answer 26

BILINGUALS SLOWER AT SWITCHING FROM 2ND LANGUAGE (HARDER TASK) TO 1ST LANGUAGE (EASY TASK) - SWITCH COST IS GREATER BECAUSE INHIBITING THE MORE COMPLEX SCHEMA HAS A COST

Question 27

Neural correlates of task switching

Answer 27

Process of task switching involves superior medial regions (lesions = greater switch cost), but making ERRORS is related to interior medial regions.

Question 28

Role of Inhibition in these tests

Answer 28

Slowing of response time when switching from hard to easy tasks - discarding previous schema and setting up a new one. Reflects difficulty in inhibiting old task. SWITCH COST

Question 29

Hot vs Cold control processes

Answer 29

Hot stimuli - affective or reward related (food or money) , associated with ORBITOFRONTAL CORTEX (connections with posterior affective areas) Cold stimuli - cognitive (sensory dimensions such as shape or colour) - lateral frontal cortex - tests of executive functions

Question 30

What is reversal learning?

Answer 30

learning that a previously rewarded stimulus or response is no longer rewarded - HOT CONTROL PROCESS

Question 31

Task switching

Answer 31

discarding a previous schema and establishing a new one - COLD CONTROL PROCESS

Question 32

Dias et al 1996 - monkeys study

Answer 32

Trained to respond to certain items through reward Post lesion training - reversal learning, same shapes and lines but rewarded for different shape (UNLEARN OLD RULE) Dimension shift - new shapes, rewarded for a certain line (learn a new rule)

Question 33

What did Dias et al 1996 find?

Answer 33

Orbitofrontal lesion = impaired reversal learning, intact set shifting Lateral frontal lesion = intact reversal learning, impaired set shifting

Question 34

What does the Dias et al 1996 findings show?

Answer 34

Dissociable neural correlates for control of reward related (hot) VS cognitive (cold) Distinction between brain areas responsible for hot and cold control processes could explain individuals with PFC lesions who are: - Impaired in the real world - impaired social behaviour - hot salient rewards for appropriate social interactions (in group benefits) - SPARED in lab tests of executive function - cognitive dimensions such as shape and colour without salient rewards (cold)

Question 35

What is the somatic marker hypothesis (Damasio 1996)

Answer 35

Emotional and bodily states associated with previous behaviours are used to influence decision making

Question 36

Where are somatic markers stored?

Answer 36

In orbitofrontal / ventromedial pre frontal cortex

Question 37

What is the Iowa Gambling Task - Denburg & Hedgcock 2015

Answer 37

Participants given a loan of £2000 Choose cards from one out of 4 decks Gain vs Loss A + B = big gain but bigger loss C + D = smaller steady gain but less loss

Question 38

What does the Iowa Gambling Task find

Answer 38

- Control group - learn to switch from bad decks to good decks and show anticipatory skin conductance response when selecting from risky deck - Patients with orbitofrontal prefrontal cortex lesions fail to switch from bad to good decks. Don't show anticipatory skin conductance response when selecting from risky decks - Show intact performance on other executive function tests : could be a failure of reversal learning

Question 39

Posterior prefrontal cortex and executive functioning

Answer 39

Implements tasks with a single goal - Response mapping (red stimulus = press left button)

Question 40

Anterior prefrontal cortex and executive functioning

Answer 40

Implements multiple tasks simultaneously - complex mapping (red stimulus = press left button only if stimulus is a vowel) - Involved in multi tasking - requires task switching and maintaining future goals in mind, whilst dealing with current goals

Question 41

Koechlin & Summerfield, 2007 - Hierarchical organisation of executive functioning.

Answer 41

Anterior -> posterior gradient for complex to simple tasks

Question 42

What is the left lateral prefrontal cortex involved in?

Answer 42

Task setting - maximised when open ended such as problem solving

Question 43

What is the right lateral prefrontal cortex involved in?

Answer 43

Task monitoring - linked to sustained attention and maintaining focus / keeping on task

Question 44

What task is impaired after lesions of both left and right lateral PFC?

Answer 44

WISCONSIN CARD SORTING TASK Left = longer switch costs Right = error prone (failure of response inhibition)

Question 45

Anterior cingulate cortex dorsal region

Answer 45

implicated in executive functioning

Question 46

Anterior cingulate cortex ventral region

Answer 46

implicated in emotional processing

Question 47

What is the role of the anterior cingulate cortex?

Answer 47

How we change our behaviour after making an error - slower / more accurate. Lesions involved in error rates not accuracy.

Question 48

What is error related negativity

Answer 48

ERP detected at the scalp when an error is made