Pre-adult Brain Development

  • Created by: OMAM
  • Created on: 12-01-18 10:29

Early Brain Development

Spinal cord and brain well developed

Parts of the brain become connected afer birth

Huge number of synaptic connections made during the first few years

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Adolescent Brain Development

Grey matter reaches peak volume

Grey matter decreases in density (synaptic pruning)

Pre-frontal cortex develops last

(The brain develops back to front)

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Brain Development and Risk Taking

These two parts of the brian play a vital role in risk-taking behaviour...

Limbic System:

This is responsible for processing social and emotional information

The issue with this is that it develops earlier than the pre-frontal cortex, so for a period of time it dominates theexecutive controls of the pre-frontal cortex

As a result, risky decisions might become more common and more likely to occur under higher levels of social influence. For example, adolescents might make poorer decision about getting into fights than adults would.

Ventral Striatum:

This area of the brain is often referred to as the 'reward centre; because it is highly sensitive to rewards

The issue with this is that adolescents' neurological function makes them sensation-seeking and drawn to novel behaviours. because thepre-frontal cortex is not fully mature, adolescents do not manage therisk involved in these activities in the same wayas adults can.

As a result, early maturation of this brain part encourages adolescents to engage in more adult activities that reap rewards, e.g. drinking, drugs, and to seek independence from their families.

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Environmental Factors Affecting Brain Development

If we the information from the previous slide together (ventral striatum and limbic system) we have adolescent brains that tend to engage in riskier behaviour, as they don't have the pre-frontal cortex to act as a break and assess the consequences.

However, neurotransmitters may also affect how impulsive an adolescent is. This can be explained by looking at a neglected child...

A neglected child may engage in risk taking behaviour when they are older, because being neglected results in lower levels of the neurotransmitter serotonin, which is linked to mood, along with more impulsitvity. As result, they don't think about the consequences, and therefore are more involved in risky behaviour

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Key Research: Barkley-Levenson and Galvan (2014)

Aim: Whether the adolecents attach more value to rewards tan adults do


Subject Value (SV): The avlue an individual places on a stimulus

Expected Value (EV): The sum of all the possible outcomes of a particular choice multiplied by their probabilities

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Key Research: Barkley-Levenson and Galvan (2014)


19 healthy, right handed adults (25-30)

22 healthy, right handed adolescents (13-17)

Self-selected - They were recruited through poster and internet advertisements, and a database or prior research participants

Prior to the experiment, participants reported that they didn't have...

  • Any prior disgnosis of psychiatric or neurological illness or development delays
  • Any metal in their bodies
  • Not taking psychoactive medication
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Key Research: Barkley-Levenson and Galvan (2014)


Quasi experiment conducted in a laboratory setting, using an independent measures design

IV: Whether the participant was an adult ot an adolescent

DV: The performance on a simplemisxed gambles game during fMRI


Participants were given $20 to keep for a week before the experiement began, so that they could develop an ownership over it

They were familiarised with the MRI environment by having a mock trial in a mock scanner

They were informed that there would be an opportunity to win up to $20 more

192 trials

Decided before each spin if they were willing to gamble or not

24 gain-only trials and 24 loss-only trials

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Key Research: Barkley-Levenson and Galvan (2014)


The higher the expected value the greater the influence of the response in adolescents - 'hyperactive reward sensitivity'

'Hyperactive Reward Sensitivity' suggests adolescents were focused more on higher amounts they could win, than smaller amounts they could lose

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Strategies to Reduce Risky Behaviour

In the past, the governement educated groups of people to make them aware of the consequences posed by risky behaviour. However, this didn't work, as peopel already knew the risks.

Now, a new strategy has been enforced...

... CHANGE THE CONTEXT! (in which risks will happen)

The focus was putt on driving, as a link between the amount of passenger and time of day a person is driving has been found to increase risky behaviour

The more passengers in the car would create peer-pressure, in turn, increasing the chance of risky behaviour

Driving at night tim has also been found to increase risky behaviour - however, this is because most adolescents engage in drinking at night time

As a rsults, some countries have enforced restrictions...

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Strategies to Reduce Risky Behaviour

Graduated Driving Licensing Schemes (GDLS)

This is not in place in UK, but is in different countries around the world

The scheme essentially features one or more probationary periods for new drivers

In USA...

  • Newly qualified and young drivers have a night time curfew - 10pm to 5am
  • They are banned from carrying passengers under 30, except in the presence of an adult
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Strategies to Reduce Risky Behaviour

Extra Information:

Drivers aged 16-19 (UK) are more than twice as likely to die in a car crash

Adolescent brains are more senstitive tp social and emotional information.

Interventions that restrict the influence of these factors on decision making may be more effective than education programmes

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