L20. Prefrontal Cortex Flashcards
The frontal lobe makes up 30% of brain volume and has a diverse range of functions. What are some of these? [3]
Executive Functioning
- Motor Control
- Language
- Higher level congnition
What is meant by the term executive function?
An umbrella term that describes inter-related processes responsible for goal directed, purposeful behaviour
Often includes social and emotional behaviour as well
What are the 3 main parts of the pre-frontal cortex? Describe each one anatomically
- Dorsolateral: top and side view of the cortex
- Medial: where the two hemispheres come together
- Orbital: Underneath the cortex (from below)
What is the dorsolateral prefrontal cortex responsible for?
Traditional executive functions: thinking and high cognitive function
- Working memory
- Response selection
- Planning and organising
- Hypothesis generation
- Flexibility maintining or shifting set (between competing demands)
- Insight
- Moral judgment
What vessel supplies the dorsolateral prefrontal cortex?
The middle cerebral artery (MCA)
What is the medial prefrontal cortex responsible for?
Emotional and motivational interface (not mood)
- At most extreme may see akinetic mutism
- Movitivation: deficit will show apathy and indifference
- Initiative
What vessel supplies the medial prefrontal cortex?
The anterior cerebral artery
What is self-awareness?
Knowing your place in the world and the place of the world around you:
- Attribution of emotions in other people
- the areas involved in attribution in self is co-localised with others
- Damage to the areas of the prefrontal cortex (medial) that control these areas show egocentricism
What is the orbitofrontal prefrontal cortex responsible for?
It is highly connected to the limbic areas
- Filtering system: emotion, cognition and social
- Impulsivity
What vessel is the ortibo prefrontal cortex supplied by?
The anterior cerebral artery and the middle cerebral artery
What do people with lesions in the orbital prefrontal cortex do in comparison with normal people?
They tend to rush and do things without thinking about them - forgo accuracy for timing
Describe the development of executive functions
Executive functions are not present at birth, and have a specific pattern of development.
The frontal lobe is the last area of the brain to develop and is also one of the first/earliest to start degenerating.
- Lower order functions develop first
- Higher order (set shifting and reasoning) develop later
Damage to the brain during development causes severe impact on these abilities
The development of frontal lobes is a dynamic process involving positive and negative processes. What is meant by this?
Development occurs until about the age of 20
- Positive process: a strengthening and proliferating “use-it-or-lose-it” process.
- Negative process: a pruning where areas lacking stimulation will not proliferate and will eventually ‘die off’
Is frontal lobe dysfunction synonymous with executive dysfunction? Why or why not?
It is not
The frontal lobe is highly connected with other regions of the brain. A lesion anywhere in the complex network will compromise executive functioning.
If the brain is an executive system, then what role does the pre-frontal cortex have to executive functioning?
It is the coordinator
