Executive Functions - Week 3

Executive Functions Definition

An umbrella term for a family of top-down mental processes that enable goal-directed behaviour, often called a 'mental toolkit for success'.

Three Core Executive Functions

Working memory, inhibitory control, and cognitive flexibility.

Working Memory

Actively holding and manipulating information in short-term memory while mentally working with it or attending to new information.

Short-Term Memory vs Working Memory

Short-term memory involves holding information in mind without actively processing, attending to, or inhibiting other information.

Inhibitory Control

The ability to control attention, behaviour, thoughts, or emotions to override a strong internal predisposition or external lure.

Response Inhibition

The ability to suppress a dominant or first response to give a more appropriate, non-impulsive response.

Attentional Control Components

Selective attention (focusing on a single task while ignoring distractions) and sustained attention (staying on task for a prolonged period).

Cognitive Flexibility

The ability to flexibly adjust to changed demands, switch between tasks/mindsets, and look at things from different perspectives.

Neural Underpinnings of EFs

Functionally depend on the prefrontal cortex and its connections with the anterior cingulate cortex and parietal cortex.

Prefrontal Cortex Development

One of the last brain regions to mature (usually early 20s), but retains lifelong plasticity to environmental influences.

Importance of Executive Functions

Stronger predictors of achievement, health, wealth, school readiness, and quality of life than IQ or socioeconomic status.

Infant Executive Functions

Infants (0-2 years) exhibit early goal-oriented behaviours such as searching for hidden toys or detour reaching.

Middle Childhood Executive Functions

During middle childhood (6-12 years), inhibitory control, working memory, and cognitive flexibility improve dramatically, though inhibitory control remains challenging.

What are the impairing symptoms of ADHD?

Inattention and/or hyperactivity-impulsivity.

What are the three dominant phenotypes of ADHD?

Inattentive, hyperactive/impulsive, and mixed.

At what age does ADHD typically begin?

Before age 12.

Can ADHD symptoms be explained by any other condition?

No, they cannot be explained by any other condition.

Critical vs Sensitive Periods

Critical periods result in irreversible changes with little/no residual plasticity, whereas sensitive periods show residual plasticity after the period ends.

Environmental Enrichment & Movement

Physical activity and environmental enrichment increase dendritic branches, synapses, and neurogenesis in the hippocampus.

Aerobic Fitness and EF in Children

Higher-fit school-aged children show greater accuracy and attentional resource allocation on executive control tasks like the flanker task.

Acute Exercise Effect

A single bout of ~20 minutes of moderate-to-vigorous aerobic exercise temporarily improves executive function performance.

FITKids Intervention Findings

A 9-month after-school physical activity program for children led to positive changes in aerobic fitness, BMI, inhibition, cognitive flexibility, and working memory.

Acute Exercise in ADHD

A single bout of 15-30 minutes of moderate-to-vigorous physical activity temporarily facilitates executive functions in children with ADHD.

ADHD and Health Risks

Children with ADHD are at risk for health conditions associated with reduced life expectancy.

Research on Enrichment and Movement

Most research on enrichment and movement is animal-based, while human research is limited.

Early Deprivation Effects on EFs (6 Months)

Early deprivation has detrimental effects on the development of executive functions.

Cumulative Period of Development

A developmental phase where effects accumulate and build upon prior stages.

Preschool Motor Function and Executive Function

In preschool-aged children, motor function test performance is linked to executive function rather than general physical activity levels.

Challenging Tasks and EF Performance Preschool

Better performance on challenging motor tasks may be due to children with better EF functioning performing better.

Inhibitory Control in Children vs. Adults

As a rule, inhibitory control is disproportionately more difficult for children than adults.

Knowledge vs. Implementation in Children

Just because a child knows what to do, does not mean they will be able to implement it, often because of limits to their inhibitory control ability.

Kobilo et al. (2011) Finding

Demonstrated that voluntary wheel running improves learning and memory in mice.

Running and Neurogenesis (Kobilo 2011)

Physical activity promotes the generation of new neurons in the adult hippocampus.

Duration of Exercise Benefits (Kobilo 2011)

The cognitive benefits of running persist for several weeks after the cessation of the exercise regimen.

Task Complexity and Running (Kobilo 2011)

Running particularly enhances performance on more complex cognitive tasks requiring hippocampal function.

Translational Relevance of Kobilo et al. (2011)

Provides a biological model for how human aerobic exercise improves cognitive function and executive control.

Age-Based Evidence for Physical and Aerobic Fitness

Most evidence focuses on ages 6-12, whereas data for ages 3-6 is limited.

Prenatal Exercise (Animal Models)

Benefits offspring neurocognition and protects against neurological consequences of stress exposure.

Prenatal Exercise (Human Evidence)

Limited, but emerging research is promising for assessing physical activity on postnatal neurocognition.