Neural development

Question 1

Why would we as developmental psychologists be interested in neural development?

Answer 1

• It allows us to examine physical brain growth, or development of functional networks
• It allows us to relate behaviour in development to to the structures and networks which underpin it

Question 2

What are the 3 different considerations to take into account when deciding which neuroimaging technique to use?

Answer 2

-Temporal resolution- How close in time/ time based information

-Spatial resolution- How specific can we be in terms of localisation

-Tolerance- What is the degree of tolerance needed to actually deal with it - especially needed when dealing with children

Question 3

What are the different imagining techniques

Answer 3

• EEG
  -Fmri
  -MEG
  -NRIS

Question 4

What does EEG measure?

Answer 4

Tests electrical activity in the brain, using small electrodes attached to the scalp

Question 5

Describe the spacial and temporal resolution for EEG and the tolerance

Answer 5

• Very high temporal resolution
• Low spatial resolution
• Can be used in early infancy - eg 1 month old ( typically would tape the electrodes directly to the scalp as the infants struggle with the cap) So this gets harder as you get older - eg difficult to put gel on the caps with a toddler

Question 6

What does an fMRI measure?

Answer 6

Measures changes associated with blood flow

Question 7

Describe the spacial and temporal resolution for fMRI and the tolerance?

Answer 7

• Very high spatial resolution
• Temporal resolution not good
• Tolerance: Requires stillness which can be tricky

If you need to be awake for the task, not really viable at all for infants and toddlers

There is some developing technology with noise cancelling headphones ( as the machines are very noisy) - but still very challenging

• Not appropriate if there is metal in the body

Question 8

What does an MEG measure?

Answer 8

Measures magnetic fields produced by the electrical currents in the brain

Question 9

Describe the spacial and temporal resolution for MEG and the tolerance?

Answer 9

• Extremely high temporal resolution
• Not high spacial resolution
• Requires a lot of tolerance from the participant

Question 10

How does NIRS work, what does it measure?

Answer 10

• Uses Near Infra-Red (NIR) light to measure lightscattering and absorption, allowing us to measurechange in blood flow
• Passes through the skull as if it wasn’t there- but doesn’t pass through hair as if it wasn’t there

Question 11

Describe the spacial and temporal resolution for NIRS and the tolerance?

Answer 11

• Trade off between spatial and temporal resolution- so its sort of a middle ground ( but don’t have excellent precision in either)
• Not restricted by metal in the body
• Can be used early- eg studies with neonates
• The optical fibres are really fragile - so expensive way of collecting data - but there are newer caps

Question 12

What is executive function?

Answer 12

• Think of executive functioning like the management system of the brain - the CEO
  -Governs higher level cognitive aspects of thinking
• An umbrella term for the processes underlying conscious, goal-directed thought, most often in novel circumstances

Question 13

What are some examples of things that executive function governs?

Answer 13

-Inhibitory control
-Monitoring/ updating working memory
-Planning
-Problem-solving
-Attention-switching
-Forward planning

Question 14

What are the different examples of tasks which measure executive functioning?

Answer 14

• Cloth pulling task
  -Towers of Hanoi
  -A not B error
  -Shifting - the dimension card change sort
  -Shifting: Wisconsin card Sorting task
  -Inhibition tasks: Stroop, daylight, stop signal, go/ no-go

Question 15

What is the cloth pulling task?
What does the ability to do this demonstrate?

Answer 15

-This looks at the executive function of planning in infants

-A test of means-end behaviour Willats (1999)

What -
- Present 6-8 month olds which an object which they can only retrieve by an intermediary action
- They will put the object on a cloth - which will be out of their reach- but the cloth will be in their reach
- So if they understand that they have got to grab the cloth to pull it, shows a degree of planning

Question 16

What do different 7 vs 8 month old babies demonstrate in terms of the cloth pulling task? So what is the development of the ability?

Answer 16

• 7-month-olds would sometimes retrieve the object by chance eg pull and pull and then discover they have got the object (withoutwatching it during their response)

WHEREAs

• 8-month-olds demonstrated intentional means-end behaviour: they looked at

their ‘goal’ when pulling the ‘means’. They clearly looked at the object and then looked at the cloth and understood what they needed to do

Question 17

What is the towers of hanoi task?

Answer 17

This is where you have one disk at a time, you have the move them across and remake the tower

You can never put a larger tile on top of a smaller tile

Question 18

What does it mean to be able to compete the towers of Hanoi task in terms of executive functioning?

Answer 18

You have got to plan ahead serval moves in advance

Therefore deals with problem solving and planning

Question 19

How do we see the development of this ability to complete the towers of hanoi task?

Answer 19

• Improvements with age
• So the graph looks at the % of people who can execute it for the first time perfectly
• When the problem length increases ( how many tiles there are, the younger children struggle significantly)

Got to keep in mind that as you add more tiles, its not just a linear increase in difficulty, because you are also having to manage and execute subgoals- eg in order to do that, ask got to to this

So the ability to do that improves massively from 4-6 years

Question 20

What area of the brain is executive function strongly associated with?

Answer 20

Pre Frontal cortex

Question 21

Why would the pre-frontal cortex need to be the central executive?

Answer 21

• The brain is a bit like a computer processing information.
• Cognition can be thought of as the flow of information through a series of stores

(Atkinson & Shiffrin 1968).

• Baddeley & Hitch (1974) propose that there is a central executive controlling what to attend to, how to encode it, and what to prioritise ( so there has got to be a central executive for all of this to work)

The idea is that the PFC might be this central executive telling us what to pay attention to

Question 22

What happens with the PFC in terms of development?

Answer 22

• The PFC changes throughout childhood and into adolescence – including synaptic pruning; increased myelination & connectivity; increase & subsequent decrease in gray matter
• NOT one of the areas that develops super early
• Huge increase in myelination observed in first year of life, and latest to develop in frontal lobes (Deoni et al 2011)
• Myelination - Improves communication speed
• Takes a long time for the myelination to reach the front of the brain

Question 23

What is one of the most famous tasks to test executive functioning?

Answer 23

A not B task

Question 24

Describe what the A not B error is?

Answer 24

• Would do this with 8-12 months age
• Hide something from the infant, they look for it, hide it again, they look for it - do this on repeat
• Hide it in another location, even though they have seen us do that, they will still look for it in the original location
• Therefore they make what we call a perseverartive error
• They are unable to inhibit this pre-potent response and actually adapt to the new information

Question 25

What happens with the A not B task in terms of development with age?

Answer 25

- With age, errors decrease, as does the delay period over which the child will search correctly - This demonstrates difficulties in set-shifting, inhibition and working memory

Question 26

What neural evidence do we have in monkeys regarding the A not B error?

Answer 26

- Diamond (1990) showed that in monkeys, A-not-B task performance was governed by the PFC - Infant monkeys with lesions of dorsolateral prefrontal cortex showed no evidence of passing at delays of 2,5, or 10 sec even by the end of their testing - Lesions of dorsolateral prefrontal cortex produced a profound deficit on the A-not-B task as long as any demand whatsoever was placed on memory Therefore showing correlation with executive functioning and the prefrontal cortex

Question 27

What neural evidence do we have relating the A not B error to the PFC in humans?

Answer 27

- Bell & Fox, 1992. EEG differences in 7-12 month old infants who can vs those who cannot solve the A not B task after a long delay: -Power of EEG signal at frontal electrodes (lots of change in strong group) -Coherence of EEG signal between front and back electrodes Therefore they are arguing that it is clearly the frontal region of the brain in charge here, but the extent to which it is talking to other regions is really important too - Individual differences in brain activity (related to maturation of PFC)explain some of the individual differences in A not B performance

Question 28

What are the two different task related to shifting?

Answer 28

- Dimensional card change sort -Wisconsin card sorting task

Question 29

What is the dimensional card sorting task an example of?

Answer 29

Attentional shifting

Question 30

What is the dimensional card change sort?

Answer 30

What: - Normally done with toddlers of 3-4 years of age and up - This is where you would change the rules on the toddler - Asked to sort a stack of cards either by colour or shape eg -Might start off with saying that they are going to play the rabbit game, you could would give them a bunch of rabbit cards, and they have got to put them on the pile of rabbits -Then you might say we are going to play the boat game, and put all of the boats into a pile -Then the shape game, rabbits go in one place and boats go in one place -Then the silly shape game eg all the rabbits go on the boat pile and the boats go on the rabbit pile -Then play the colour game ( so shifting this attention from shape — colour can be quite a demand -Could then add difficulty to that with the silly colour game as well

Question 31

What does the dimensional card change sort test?

Answer 31

- These rules changes test your cognitive flexibility and your ability to adapt and inhibit the rules that you have just learned - So its not a question of comprehension, as they can understand the rules, sometimes they can't actually complete the task

Question 32

What are the findings of the dimensional card change sort test?

Answer 32

- Despite answering correctly to questions concerning the game ‘rules’, at 3 years children typically continue sorting cards with respect to the first dimension.- unable to shift from shape- colour, colour-shape etc - By 4-5 years they switch successfully. - They lack the ability to switch attention between aspects of the scene (colour and shape) – a central executive task. - At 3-4 years, executive function is still developing- even at a basic level

Question 33

What is the Wisconsin card sorting task?

Answer 33

- You dont know the rules, you have just to work out whether you are right or wrong as you play - Again specifically looks at cognitive flexibility

Question 34

What are 4 examples of tasks requiring inhibitory control?

Answer 34

- Stroop task is one famous example, but requires literacy - Day/Night task is commonly used - Stop-signal task - Go/NoGo task

Question 34

What is the neural evidence behind the wisconsin card sorting task?

Answer 34

- Direct evidence that developmental changes in PFC function accompany changes in executive function (Moriguchi et al, 2009). - Children do card sorting task while brain activity is recorded via NIRS(near infra-red spectroscopy – measuring blood oxygenation related to brain function) Nearly all aged 5 but only 75% aged 3 successfully switch rules Change in blood oxygenation in prefrontal areas between control phase(sort blank cards) and study. Compare 3s who pass vs fail (persevere). Their oxygentated blood flows to other regions — not pre frontal cortex Therefore we have direct neural evidence for the pre-frontal cortex being involved and related this executive functioning

Question 35

What is the stop-signal task, and which group are particularly implicated by this task?

Answer 35

Press left for A, right for B If S appears, stop your response and don’t press anything So its the ability to inhibit pressing Those with ADHD, this is an area thats really implicated They show big changes in the pre-frontal cortex compared to controls

Question 36

What is the go/no go task- what are the neural implications of this?

Answer 36

Press a button when the letter X appeared, but only when it waspreceded by the A (Go condition). When an A is followed by anotherletter, inhibit your prepared response (A-not-X, NoGo condition). - All ages: medial frontal cortex more active during NoGo task. - Children only: additional posterior source, different for 6-7yrs and 9-10yrs.

Question 37

Overall, what can we say about executive function and neural regions?

Answer 37

- Lots of evdeicne that these EF tasks are related to the PFC - Some of the specific sub components of executive functioning ( eg inhibition, working memory) are related to more precise regions of the prefrontal cortex So whether executive functioning is one thing or whether it's an umbrella term for a whole bunch of processes - remains to be seen Eg very difficult to test inhibition without introducing a working memory component