Executive Function

Question 1

What are executive functions?

Answer 1

The ability to plan actions to reach a goal, guide, or control behaviour towards the goal
— use information flexibly, think abstractly, make references
Must be exerted in situations when there is no existing plan/ template/ experience for how to act
Required when typical responses must be overridden or inhibited
AKA Cognitive control

Question 2

Cognitive control

Answer 2

A term indicating a process in which someone is guiding their own thoughts and actions

Question 3

How many functions contribute to the performance of executive abilities?

Answer 3

More than one, therefore, it’s difficult to link each function to a specific brain region

Question 4

Executive deficits

Answer 4

Most commonly observed after damage to the frontal lobe, including the white matter area connecting frontal regions to other area
— difficulties in executive functioning can occur despite normal functioning in other “intellectual processing areas”

Question 5

The lateral prefrontal cortex

Answer 5

• Dorsolateral
• Ventrolateral
• Orbitofrontal
• Premotor
  (check slides to practice labelling location)

Question 6

Goal-directed behaviours

Answer 6

• guiding behaviour towards a goal is multifaceted
• losing a facet can derail the entire plan
• completing a task requires a number of skill
• functions rely on a pattern of activity within overlapping portions of the frontal lobe + the degree it interacts with other brain regions

Question 7

Skills needed to complete a task

Answer 7

• staying on task
• sequencing information
• modifying strategies
• using knowledge in your plans
• monitoring actions

Question 8

Creating and maintaining a goal

Answer 8

• required for executive functioning
• most basic prerequisite for meeting a goal is staying on task
• those with frontal lobe damage have issues staying on task

Question 9

Creating and maintaining a goal: Task sets

Answer 9

Task set: process that designated which information is task relevant
Stroop test can test this: a cue 1.5 seconds before the stimulus says what information should be identified
Lateral prefrontal cortex becomes active during the cue period, before the stimulus
—– greater degree of activation causes a less competing colour name causing slowed responses
Prefrontal areas help us stay on task

Question 10

Sequencing and Planning

Answer 10

• to reach a goal, you need to know what steps need to be taken and what order to take them in
  »> requires knowing what comes before and after, what’s been a accomplished, what needs to be performed
  »> dorsolateral prefrontal regions may be important in sequencing items because they support executive processes that act on information maintained in working memory

Question 11

Self-Ordered Pointing Task (slides)

Answer 11

(6 items are given on a screen, participant must pick any item they haven’t picked before, items change location each time)
- reveals deficits in sequencing
- observed after frontal lobe damage, notably laterally
- regions also active neurologically-intact individuals when they must make a recency judgement

Question 12

Choosing a Sequencing Strategy

Answer 12

• Another important aspect is the ability to choose which sequence/ strategy allows a goal to be attained
• Patients with frontal lobe damage are less likely to report they are using strategies
• One way to assess strategy is the Tower of London Task (move balls to the goal position in as little moves as possible/ in recommended number of moves)

Question 13

Task-switching

Answer 13

• reaching a goal is not always linear
  — there are often things that require task-switching
• The neuropsychological test used is the Wisconsin Card Sorting Test (WCST) (told to sort cards in a certain way, then told to sort in another way)
  —– neurologically intact people adjust their responses accordingly in this test
  —— A variety of brain areas are activated during the WCST: Dorsolateral Prefrontal Cortex, Ventrolateral prefrontal cortex, inferior parietal lobe, temporoparietal association cortex, the basal ganglia

Question 14

Task-Switching and the Brain

Answer 14

A variety of brain areas are activated during the WCST:
- Dorsolateral Prefrontal Cortex, Ventrolateral prefrontal cortex, the inferior parietal lobe, temporopariteal association cortex, the basal ganglia
Task switching is likely directed by an executive control system that is independent of the systems that perform each individual task

Question 15

Frontal lobe damage and task switching

Answer 15

patients with left frontal lobe damage have a specific deficit in task-switching
Increasing activity in this area (the left DLPFC) via transcranial direct current can augment task-switching abilities
- inferior frontal junction is also implicated in task-switching

Question 16

Psychological Intertia

Answer 16

Hard to start an action, once engaged, hard to stop
- damage to medial frontal areas, including the supplementary motor area and anterior cingulate
- regions of the medial prefrontal cortex may be involved in determining how much effort will be exerted to reach a goal

Question 17

Inhibition: Go? No-Go Task

Answer 17

Person responds by pushing a button when certain stimuli appear and withholding to other stimuli
- difficult when No-Go trials are rare, because Go is expected
- Witholding a response has consistently been found to engage a right-sided network of frontal brain regions

Question 18

Inhibition: Stop-Signal Task

Answer 18

The person must respond to a stimulus as quickly as possible
In some trials, quickly after the stimulus is presented another signal occurs quickly that indicates you should stop
- activiates similar right-side networds of brain regions
- Both this and go/no-go involve the dorsolateral prefrontal cortex, the anterior cingulate, the SMA (pre-SMA), insula, and parietal regions

Question 19

Self-Monitoring and Evaluations and Brain Damage

Answer 19

The ability to evaluate one’s own behaviour is affected by frontal lobe regions
— metacognitive awareness is distrupted by patients with left OR right frontal lesions
— frontal damage impairs the ability to detect errors and modify ongoing behaviours to take a corrective action (especially right)

Question 20

Error-Related Negativity

Answer 20

Occurs ~100ms after an error
Amplitude increases under conditions in which response accuracy is emphasized
The larger the error, the larger the ERN
A variety of converging evidence suggests that the ERN component arises from rostral regions of the anterior cingulate cortex (ACC)

Question 21

Self Monitoring and Evaluation

Answer 21

We have a set of brain mechanisms that helps to monitor our performance and detect error
- Theory: the anterior cingulate detects that an error has been made
—– but, even when someone is not aware they made an error, an ERN (Error-Related Negativity) can be detected
—– It could be the ERN is providing an undifferentiated signal that something is amiss

Awareness of an error is indexed by error positivity (Pe)

Question 22

Error Positivity (Pe)

Answer 22

Frequently follows ERN by about 200-300 ms
— likely generated by the insula, which is associated with interoception
Increases when there’s awareness of an aerror

Question 23

Introception

Answer 23

The ability to sense the physiological condition of the body

Question 24

ERN in people with ADHD and Anxiety

Answer 24

Anxious people have an increase ERN
Those with ADHD have decreases in ERN and Pe

Question 25

Higher-Order Thinking

Answer 25

- Conceptual Aspects of thought >> Being able to think abstractly and conceptually >> ability to deduce rules or regularity >> ability to be flexible and respond to new things One deficit by those with executive dysfunction is an inability to process things abstractly

Question 26

Nonverbal Analogical Reasoning Problemes

Answer 26

- Use to check executive dysfunction Wait for slides

Question 27

Reasoning and the Brain

Answer 27

- Various regions are activated during analogical reasoning >>> frontopolar, dorsolateral prefrontal regions and anterior insula, parietal cortex

Question 28

Frontopolar cortex and reasoning

Answer 28

Distinct areas in the frontopolar cortex activate more for visuospatial analogies compared to for semantic analogies

Question 29

Brain regions for Making rules and inferences

Answer 29

- A number of PFC (prefrontal cortex) regions are required to use rules to guide actions --- Ventrolateral PFC needed to retrieve knowledge of rukes --- Dorsolateral PFC with selecting or influecing how rules should be used to guide responding either directly or because it has rules in working memory --- Cells in the Lateral PFC discriminate between cateogories of items (slides) --- inference is involved in the prefrontal cortex

Question 30

Cognitive Flexibility

Answer 30

People with ED struggle with this, looking at situatings in various ways and producing a variety of behaviour ---- flexibility is needed in new situations and new reactions to old situations --- **orbitofrontal cortex** aids in flexible behaviour --- **Frontopolar Cortex** helps reorient task goals towards novel situations or opportunities

Question 31

Judgement and Decision Making

Answer 31

Frontopolar cortex: abandoning the current strategy and starting a new one Medial Orbitofrontal regions: calculate present vs. future rewards --- research uses delay discounting paradigm --- DLPFC (?) engaged when an individual overcomes the temptation to take an immediate reward

Question 32

Working Memory and Executive Function

Answer 32

DLPFC may be important in executive function because it supports working memory --- working memory -------- keeps a goal in mind -------- helps understand timing and relationships between items and events -------- needed to create, follow rules, + make inferences and/ or understand the relationships between items and the world

Question 33

Meidal and Lateral PFC

Answer 33

Lateral PFC Organization for EF slides/ figures