Pre-adult brain development Flashcards
Background - risk taking behaviour
Casey find
Reduced activity in inferior frontal gyrus and increased activity in ventral striatum linked with inability in delaying gratfication
prefrontal cortex = decision-making, controlling impulses, ability to assess risk
amygdala = regulating emotions + controlling impulsive behaviour
ventral striatum = wanting rewards immediatly
Describe developmental processes
Synaptic pruning
Dual systems theory
SYNAMTIC PRUNING
- synapses are no longer used or lost
- occurs throughout childhood
DUAL SYSTEMS THEORY
-ventral striatum matures earlier than prefrontal cortex
- prefrontal cortex isn’t developed enough to help weigh up risk
BACKGROUND
What did Johnston et al find
Changes in ventral striatum matches the increase in arrests for criminal behaviour eg. drug taking
BACKGROUND
Su et al’s sample
40 younger adults + 40 older adults
Taiwan
BACKGROUND
Su et al’s results
Younger adults had greater activity in their ventral striatum
whereas older adults had more activity in prefrontal cortex
when making decisions about gambling in EV tasks
BACKGROUND
Methodological issues in Su et al
Sampling bias -
males and females so no gender bias
ethnocentric - Taiwan only, but supports findings in America
Reliability
fMRI scan which is easy to replicate
Validity
lab based gambling task performed in fMRI so low ecological validity
BACKGROUND
What did Tottenham find
Neglect when a child is young causes lasting damage to the amygdala and ventral striatum
which are both involved in emotional and impulsive behaviours
BACKGROUND
Sample of De Bellis
Teenagers with or without alcohol use disorder
Male and Female
American Sample
BACKGROUND
Findings of De Bellis
Participants with alcohol disorders had smaller prefrontal cortex
Prefrontal cortex significantly correlated with amount of alcohol teens consumed
BACKGROUND
Methodological issues in De Bellis
Sampling bias
- only 17 year olds so age bias
- no gender bias as males + females
- ethnocentric - American teenagers
Reliability
- MRI scans to collect brain volumes
- more replicable
Validity
- other factors could affect brains, not just alcohol use disorder
- could have difficult backgrounds
KEY RESEARCH
Aim of Barkley-Levenson and Galvan
Research Method
Aim - too see if adolescents would be more sensitive than adults to increased EV (by accepting more gambles) (Expected value is EV sum of all possible outcomes)
Laboratory based qausi experiment
- can’t control if adolescent or adult
KEY RESEARCH
Sample of Barkley-Levenson and Galvan
19 adults and 22 adolescents
Male and Female, All right-handed
Self-selected sample recruiters by posters online + participants from university of California
All healthy be self-report (no taking meds for psychological disorders/metal in body)
KEY RESEARCH
Procedure of Barkley-Levenson and Galvan
Informed consent obtained from adolescents, parents and adults
Participants were asked about monthly spending money and given $20 as ‘playing money’
They were told the gambles will affect how much money they can take home
During the fMRI scan each participant completed gambling task
Shown on screen spinner each half presenting a gain or loss
KEY RESEARCH
Results of Barkley-Levenson and Galvan
Increasing the expected value (EV) made people more likely to accept the gamble
Effect was significantly greater in adolescents than adults
No link between amount of disposable income participants and gambling
fMRI showed as EV increased, more activation in prefrontal cortex and less activation in amygdala
Ventral striatum showed greater activation in adolescents when there was increased EV
KEY RESEARCH
Generalisability
only adolescents between 13-17 yrs old
> not representative of older adoles
self selected sampling
> volunteers are often outgoing+impulsive
> may be more likely to take risks than wider population
carried out in USA
> Western culture
> non-western cultures have different view
