Prefrontal cortex and executive functioning

Question 1

How much of the brain volume is occupied by the frontal lobe?

Answer 1

30%

Question 2

What are the principles of subdivision of the frontal lobe?

Answer 2

Subdivision based on:

cytoarchitecture

thalamic connections

functional properties

Question 3

Which types of connections are generally used in the subdivision of the frontal lobe based on thalamic connections?

Answer 3

Afferent connections

Efferent connections

Question 4

Are afferent or efferent connections usued more commonly to subdivide the frontal lobe based on thalamic connections?

Answer 4

Afferent connections

Broadly map onto Brodmann areas

Question 5

Describe some examples of subdivision of the frontal lobe based on functional distinctions?

Answer 5

Motor area

Premotor area

Prefrontal area

Broca’s area

PICTURE FROM SLIDE 7

Question 6

What was the Phineas Gage lesion study useful for?

Answer 6

Understanding frontal lobe functioning

Question 7

Which part of Luria’s functional system corresponds to the frontal lobe?

Which functions is it responsible for?

Answer 7

Anterior unit

Planning, executing and verifying behaviour

Question 8

What is executive functioning?

Which lobe of the brain is it associated with?

Answer 8

An umbrella term to describe the inter-related processes responsible for goal-directed, purposeful behaviour

Incudes emotional and social behaviour as well as cognition

Considered a frontal lobe function

Question 9

What are the major subdivisions of the the pre-frontal cortex?

Answer 9

Dorsolateral pre-frontal cortex

Medial pre-frontal cortex

Orbitofrontal prefrontal cortex

Question 10

What are the major functions of the dorsolateral PFC?

Answer 10

Traditional executive functions:

Working memory

Response selection

Plannig and organising

Hypothesis generation

Flexibility maintaining

Insight

Moral judgement

Question 11

What is the major arterial supply to the dorsolateral PFC?

Answer 11

Middle cerebral artery

Question 12

Decsribe the functions of the medial PFC?

Answer 12

Emotional-motivational interface:

Apathy

Initiative

Indifference

Akinetic mutism at most extreme

Question 13

What is the major arterial supply to the medial PFC?

Answer 13

Anterior cerebral artery

Question 14

Issues with self-awareness can arise from lesions in which part of the frontal lobe?

Answer 14

Medial PFC

Anterior cingulate

Question 15

Which deep brain strucutres is the orbitofrontal PFC highly connected to?

Answer 15

Limbic areas

Question 16

Describe the functions of the orbitofrontal PFC?

Answer 16

Inhibiton (emotional, social, cognitive)

Impulsivity

Question 17

What is the major arterial supply to the orbitofrontal PFC?

Answer 17

Anterior cerebral and middle cerebral arteries

Question 18

Problems with impulsivity are evident in individuals with lesions in which part of the frontal lobe?

Answer 18

Orbitofrontal PFC

Question 19

Describe the maturation of the frontal lobes?

Answer 19

Last area of the brain to develop

First part of brain to degenerate in ageing

Development is a dynamic process, involving both positive and negative processes (eg. proliferation vs pruning)

Question 20

What is the functional consequence of the frontal lobe being the last area of the brain to develop?

Answer 20

Executive functions are among the last abilities to reach maturity

Lower order functions develop first

Higher order functions develop later

Question 21

What is executive dysfunction?

Answer 21

Problem with execuitve functioning

POSITIVE SYMPTOMS: distractibility, social disinhibition, emotional instability, etc.

NEGATIVE SYMPTOMS: lack of concern, restricted emotion, deficient empathy, etc.

Question 22

Are executive dysfunction and frontal lobe dysfunction the same thing?

Answer 22

NO

Pathology of executive dysfunction is likely to be in the frontal lobe, but not necessarily

Prefrontal cortex is just a ‘coordinator’ of executive functioning

Question 23

Which lesions are formal neuropsychological tests most sensitive to?

Whic types of lesions are more difficult to test?

Answer 23

DLPFC lesions

Medial and orbitofrontal are difficult to formally assess

Question 24

How can DLPFC lesions be assessed?

Answer 24

Formal neuropsychological tests

Question 25

How can medial and orbitofrontal lesions be assessed?

Answer 25

Clinical judgement and history taking

Question 26

Give three examples of tasks that may be included in a formal neuropsychological test?

Answer 26

Tower of London (4 moves)

Stroop test (reading colours)

Rey complex figure test (copy drawing, assess planning)

Question 27

What are some common causes of executive dysfunction?

Answer 27

CHI
Stroke

Psychiatric conditions (eg. schizophrenia)

Dementias

Focal lesions

Inflammatory

Developmental (eg. autism)