Executive Functioning

Question 1

What are executive functions?

Answer 1

Executive functions refer to higher‐order cognitive control processes that enable goal‐ directed strategic behaviour.

Question 2

What are some examples of executive functioning?

Answer 2

Inhibitory control
Mental flexibility
Working memory

Question 3

What is inhibitory control?

Answer 3

The ability to inhibit prepotent behaviours.

Question 4

What are three clinical tests of executive functioning?

Answer 4

Wisconsin Card Sorting
Tower of Hanoi
Trail Making Test Part B

Question 5

What is the wisconsin card sorting task?

Answer 5

The one where the patient has to guess the rule about how to sort the card (based on colour, shape or number). The assessor changes the rules without telling the patient and the patient needs to figure out and switch between rules.

Question 6

What is the tower of hanoi task?

Answer 6

Three pegs with three rings. Try to rebuild what exists but on a different peg and you’re not allowed to put a larger ring on top of small ring.

Question 7

What fMRI activity was observed during a task similar to the tower of hanoi task?

Answer 7

Prefrontal cortex activation.

Question 8

What is the trail making test - part b?`

Answer 8

Scattered numbers and letters. Trace a trail switching between numbers and letters.
There’s no switching aspect to part a so to isolate frontal lobe related function, you do a subtraction of the time taken.

Question 9

Who struggles with the trail making task - part b?

Answer 9

People with damage to the prefrontal cortex.

Question 10

What are three cognitive tests associated with inhibitory control?

Answer 10

Anti-saccade task
Stroop task
Flanker task

Question 11

What is an anti-saccade task?

Answer 11

When the correct response is in the opposite direction of the stimulus. A reflexive error is if you initially look at the stimulus.

Question 12

Who struggles with anti-saccade tasks?

Answer 12

Old people, people with frontal eye field lesions and Parkinson’s Disease patients.

Question 13

What is the stroop task?

Answer 13

For each word, report the colour of the ink.

Question 14

Who struggles with the stroop task?

Answer 14

Patients with frontal lobe damage exhibit increased stroop effects.
Older adults also have a lot more trouble; make more reflexive errors and slower to respond even when they are correct.

Question 15

When it comes to aging and brain structure, wha decline is seen at an early age?

Answer 15

The lateral prefrontal cortex shows declines staring from twenties.

Question 16

What is the flanker task?

Answer 16

Press the left button if the central stimulus is ‘’, and the right button if it’s ‘’. The distractor stimulus is either compatible or incompatible. It measures how distracted the person is.

Question 17

Who struggles with the flanker task?

Answer 17

Healthy older adults have more difficulty ignoring the distracting letter

Question 18

Is the flanker effect a pure measure of inhibitory control?

Answer 18

No, the flanker effect does not provide a pure measure of inhibitory control (as is the case with the Stroop task). The flanker effect can reflect a combination of distractor inhibition and target amplification.

Question 19

What task allows for isolation of the executive functions inhibitory control and task switching?

Answer 19

Like the flanker task; three types of trial:
Pro = press the button on the same side of the stimulus
Anti = press the button on the opposite side of the stimulus
Pro/Anti = press the button on the same side when stimulus is green, and the button on the opposite side when stimulus is red.

Anti represents inhibition, and Pro/Anti represents task switching.

Question 20

Regarding the task that allows for isolation of the executive functions inhibitory control and task switching. What functions are common to pro and anti trials?

Answer 20

• stimulus detection
• stimulus localisation
• response selection
• response execution

Question 21

Regarding the task that allows for isolation of the executive functions inhibitory control and task switching. How would you isolate inhibitory control?

Answer 21

Anti minus Pro

Question 22

Regarding the task that allows for isolation of the executive functions inhibitory control and task switching. How would you isolate task switching?

Answer 22

Pro/Anti minus Anti

Question 23

What do we know in terms of older adults and inhibitory control and task switching?

Answer 23

Older adults are significantly worse in terms of inhibitory control abilities and then worse again for task switching.
Without any brain disease at all, these deficits associated with normal aging.

Question 24

What’s a good measure on working memory?

Answer 24

The n-back task

Question 25

How do n-back task fMRI data and patient data compare?

Answer 25

fMRI = In healthy adults prefrontal brain regions showed increased activation with increasing working memory load during the letter n‐back tasks. These data indicate prefrontal involvement in working memory.
Patient data = - Patients with dorsal and ventral PFC damage exhibited impaired n‐back performance, especially on the harder task (2‐back). These data indicate that working memory performance depends on prefrontal cortex.

Question 26

Did Machado and colleagues find an association between age and executive functioning?

Answer 26

Yes, age positively correlated with Anti reaction time and the inhibitory isolate (Anti minus Pro), even in young adults (18-30).
Pair this with the fact that lateral prefrontal cortex volume declines are seen in peoples’ twenties.

Question 27

Other than volume, what two other changes are happening in the brain with age?

Answer 27

Declines in cerebral blood flow and declines in cerebral blood flow regulation.

Question 28

What were the two methods that we looked at to assess cerebral blood flow regulation?

Answer 28

1. Blood flow responsiveness to metabolic demands (neurovascular coupling) = Look at CBF response to visual stimulation (specifically PCA response)
2. Blood flow responsiveness to CO2 levels = Give gas mask to increase levels globally, expect to see global response