Ch 11: Executive Function

What are executive functions?

Guidance/control of behavior toward a goal

Umbrella term to describe a set of abilities

• ability to plan

• actions to reach a goal

• use information flexibly

• think abstractly

• make inferences

What is the structure-function relationship for creating and maintenance of a goal/task set?

Lateral PFC aids in creating and maintaining an attentional or task set, designating which info is task-relevant

• Staying on task and guiding behavior

• Creating and maintaining a task set is likely to involve interactions between frontopolar, lateral prefrontal, medial prefrontal, and insular regions.

Stroop Task

What is the structure-function relationship for initiation of action and effort directed towards a goal?

Medial prefrontal cortex:

• Supplementary Motor Area

• Anterior Cingulate Cortex: Integrates info about effort and reward

• Ability to initiate action (especially under effortful conditions) appears to involve the medial PFC and the connections between them

What is the structure-function relationship for inhibition?

Go/No Go Task and Stop Signal Task

These tasks activate a wide range of brain regions (mainly in right hemisphere):

• dlPFC

• Inferior frontal

• ACC

• SMA and pre-SMA

• Insula

• Parietal regions

What is the structure-function relationship for sequencing and planning?

• Rostrolateral PFC specific with sequencing abilities by selecting overall or subgoals

• DLPF

• Frontopolar regions may also be involved

Tower of London/Tower of Hanoi Task, Self-Ordered Pointing Task

• If difficulty increases → DLPFC activity increases

What is the structure-function relationship for shifting set and modifying strategies?

Frontal lobe

• DLPFC (especially in right hemisphere) damage performed worst on WCST

What is the structure-function relationship for self-monitoring and evaluation?

Frontal region

• right region

ACC, lateral PFC, insula and their interactions

What is the structure-function relationship for abstract and conceptual thinking?

Frontal lobe

What is the structure-function relationship for rules and inference?

Frontal lobe

Neurons that code for rules

What is the structure-function relationship for response to novelty?

Frontal regions

• VAN for novel stimulus catching attention

• Orbitofrontal and frontopolar cortex for flexibility

What is the structure-function relationship for judgement and decision making?

Frontal Cortex

• vmPFC- solutions for real-world problems

What is the role of working memory in executive function?

Plays a central prominent role in executive function

• Most of the components of executive function rely on working memory

What is the organization of the brain in executive function?

1. MOST IMPORTANT: Difficult to localize function to specific areas of brain tissue. Multiple regions of PFC are involved. Interactions between these prefrontal regions (anterior → posterior and medial → lateral) and other cortical/subcortical regions allow for executive control.

2. Nested hierarchy of control from posterior → anterior portions of the frontal cortex

   • Most posterior regions influenced by most immediate aspects of situation while more anterior affected by considering larger context

   • Focuses on the type of information that is used to guide control

   • Emphasizes the context in which control is implemented

3. The hierarchy is based on the nature of representations that are competing for control over action selection

   • Emphasizes the level of abstraction of information that is used to guide the selection of your action

What is the role of the lateral prefrontal region in executive control?

Creation of top-down sets

What is the role of the medial prefrontal region in executive control?

Selection at a more response-based level

Instructions and what is measured in the Stroop Task

Instructions and what is measured in the Tower of London/Hanoi task

Measures sequencing and planning

Instructions and what is measured in the Wisconsin Card Sorting Task

Shifting Set and Modifying Strategies

Instructions and what is measured in the Delay Discounting Paradigm

Measures judgment and decision-making

• Person must decide if they want a $5 discount now or a $10 discount later (week later)

Instructions and what is measured in the Iowa Gambling Task