20 - Prefrontal Cortex and Executive Function

Question 1

Difference between lochotomy and lobotomy

Answer 1

Lochotomy is cutting connections between things.

Lobotomy is removing a lobe.

Question 2

‘Executive function’
1
2
3

Answer 2

1) Umbrella term
2) Describes inter-related processes responsible for goal directed, purposeful behaviour
3) Includes emotional and social behaviour as well as cognition

Question 3

Functional subdivisions of the prefrontal cortex

Answer 3

Lateral, orbital and medial

Question 4

Functions of the dorsolateral prefrontal cortex
1
2
3
4
5
6
7
8

Answer 4

1) “ Traditional” executive functions
2) Working memory
3) Response selection
4) Planning and organising
5) Hypothesis generation
6) Flexibly maintaining or shifting task
7) Insight
8) Moral judgment

Question 5

Artery supplying the dorsolateral prefrontal cortex

Answer 5

Largely supplied by the middle cerebral artery

Question 6

Functions of medial prefrontal cortex

Answer 6

Emotional-motivational interface.
If severely damaged -> akinetic mutism (not moving or speaking).
Damage can lead to apathy, indifference, initiative.

Question 7

Artery supplying the medial prefrontal cortex

Answer 7

Anterior cerebral artery

Question 8

Functions of the orbitofrontal cortex
1
2
3

Answer 8

1) Highly connected to limbic areas
2) Inhibition (emotional, cognitive, social)
3) Impulsivity

Question 9

Arterial supply of orbitofrontal prefrontal cortex

Answer 9

Anterior cerebral artery and middle cerebral artery

Question 10

Maturation of the frontal lobes
1
2
3 a, b, c, d
4 a, b

Answer 10

1) The frontal lobe is the last area of the brain to develop
2) Also one of the first to degenerate in the aging process
3) Executive functions are amongst the last abilities to reach maturity
a) genetic and environmental factors
b) progression of development
c) ‘lower order’ functions develop first
d) ‘higher order’ eg. set shifting and reasoning develop later

4) Dynamic process of development
a) Positive processes: eg. Neuronal proliferation
b) Negative processes: eg. “pruning”

Question 11

Areas where lesions can cause executive dysfunction.

Answer 11

Most areas of the brain.
Not necessarily only in the frontal lobe.
Frontal lobe co-ordinates executive system, receives inputs from all over the brain.

Question 12

Positive symptoms of executive dysfunction 
1
2
3
4
5
6

Answer 12

1) Distractability
2) Social disinhibition
3) Emotional instability
4) Perseveration (repeating a task)
5) Impulsivity
6) Hypergraphia (writing a lot)

Question 13

Negative symptoms of executive dysfunction
1
2
3
4
5

Answer 13

1) Lack of concern
2) Restricted emotion
3) Deficient empathy
4) Failure to complete tasks
5) Lack of initiation

Question 14

Type of prefrontal cortex lesions most easily-detectable by neuropsychological tests

Answer 14

Dorsolateral prefrontal cortex.

Harder to detect medial and orbitofrontal cortex. Need to use clinical judgement.

Question 15

Stroop test

Answer 15

Names of colours written in a different colour.

Have to name the colour that a word is written in, not what the word says.