Executive funtion

Phineas Gage

• fitful, impatient, rude etc

• Had lesions to his frontal lobe

What are executive functions

→ different abilities used for planning and implementing goal-directed behaviour

• intentional/conscious

• Voluntary (top-down)

Cold vs hot EFs

Cold

• logical, low-stakes tasks

• Planning, memory, inhibition

• No emotional involvement

Hot

• high-stakes emotional tasks

• Motivation or risk/reward involved

• Social cognition

Role 2x PFC in EFs

• dorsolateral prefrontal cortex(dlPFC) = EF and cognitive control

• Ventromedial PFC is sensitive to the reward or value of stimuli

How do dlPFC and wmPFC play different roles in EF

• VmPFC has a role in emotional processing, where dlPFC is more cognitive control and executive processing

What are the 3 main executive functions

• shifting/cognitive flexibility

• Inhibition

• Updating/working memory

What are border EFs and how do we separate them

• planning = shifting and updating

• Self-monitoring = inhibition and updating

• Attentional and cognitive control = all

Cannot separate in real life, borders not clear enough

What is shifting and the 2 types

→mentally switching between different cognitive operation

• sequential shifting = rapid change from task A to B, and back to A

• Parallel shifting = tasks A and B are performed simultaneously

Tests used to measure shifting

• dual-task (parallel)

• Rule/response switching (sequential)

• WCST - Wisconsin card sorting (sequential)

Neural correlates of shifting

• dlPFC and vmPFC involved in all

• Lateralised to left hemisphere

• PreSMA is important in distinguishing parallel from sequential

• Precuneus and left-middle frontal gyrus relevant for interaction of networks

What is updating

→the executive/active part of the working memory, holds info

• Monitor, revise and replace info in working memory

• Modify, learn

• updating of the amnestic track

Paradigms used for updating

• digit or clustered conceptual span

• N-back tasks - remembering a certain character

• Other span tasks

Neural correlates of updating

• fronto-parietal regions

• Insula and cerebellum

• N-back only = basal ganglia

• Overall → thalamus, basal ganglia and regions of the cerebellum

What is inhibition and 3 types

→ ability to suppress unwanted or inappropriate actions

• inhibition of responses (suppression of automatic responses)

• Cognitive inhibition (suppression of irrelevant responses)

• Motor inhibition (suppression of motor actions already planned)

What paradigms test inhibition

• go/no go

• Stop signal

• Stroop test

• Flanker test

Neural correlates of inhibition

• peak in preSMA

• Left occipital and right temporal regions

• Left IFG

‘Global’ EF network

Widespread bilateral activation of:

• PFC

• Insula

• Basal ganglia

• Occipital regions

Less activation in:

• MFG

• Cerebellum

Explain the overlap between WM and EF

• theories often studied similarly

• Overlapping between constructs and variance in them

EF and reading comprehension, primary study

• role of updating, inhibition and shifting in reading comprehension

In a primary school study:

• EF and reading comprehension show bidirectional relations

• From first grade onwards, EF contributed to reading comprehension

• From second grade, reading comprehension contributes to EF

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EF role in stuttering

• Cognitive functions play a role in stuttering

• children who struggle with EF also stuttered more

• Differences in white matter tracts of kids

What are the two theories bethind EF and ASD

1. Executive dysfunction

2. Alteration in central coherence

EF and emotional control

• Emotional control = exerting and influence our emotions moves us towards our goals, controlled by higher functions

Executive dysfunction theory of ASD

• autistic challenges stem from difficulties with high-level cognitive processes

• Planning, WM, impulse control, flexibility

• Leads to high stress and challenges

• Not just social communication deficits

• Frontal lobe and PFC

Alteration in central coherence in ASD

• autistic people have a ‘weak’ ability to integrate info into a bigger picture

• Focus on local details and features instead

• Contextual challenges