Adolescent brain Flashcards
Galvan et al. (2007) tested children (7-11 y/o), adolescents (13-17 y/o) and adults (23-29 y/o) and the number of of risk-taking behaviours they performed.
What did pps have to do for the researchers to assess their level of risk taking?
There were 34 items that pps had to give 3 ratings each for…
a) likelihood of engaging in this activity in the next 6 months
b) likelihood of a negative consequence
c) likelihood of a positive consequence
Pps were asked how likely they were to engage in… (in the next 6 months)
- risky sexual behaviour
- heavy drinking
- drug use
- aggressive & illegal behaviours
- irresponsible academic/work behaviours
- high-risk sports
In Galvan et al.’s (2007) study, pps had a fMRI scan while they did a delayed response task.
What did this task involve?
3 pirate pictures (cues) were associated with a (initially unknown) reward (low/high)
- a cue appeared and, after a delay, pps had to indicate which side of the screen that the cue had appeared
- after another delay, the amount of reward associated with that cue was displayed
How did Galvan et al. (2007) ensure that this was an implicit learning task?
They asked pps which pictures (cues) matched with which reward
–> pps couldn’t say, which implies that it is an implicit learning task
What did Galvan et al. (2007) find in their study?
A change in signal in the NAcc was positively associated with children, adolescent and adult self-ratings of the likelihood to engage in risky behaviours, but negatively associated with their self-assessed likelihood of negative consequences for these actions
What was a bigger signal in the NAcc related to reward linked to in Galvan et al.’s (2007) study?
A bigger signal in the NAcc related to reward was linked to riskier behaviour
2 adolescents in Galvan et al.’s (2007) study had the biggest risk-taking scores and NAcc responses.
What does this suggest?
This suggests that some adolescents have a bigger response to risk-taking and reward than adults & children
Galvan et al. (2007) found an association between pps response to the reward and risky behaviour.
What was the association?
The bigger their response (to the reward), the more likely they were to display risky behaviours
Who proposed the Triadic Brain model?
Ernst, Pine and Hardin (2006)
What is the Triadic Brain model?
A model of which brain areas respond to reward and risk
What is the basis of the Triadic Brain model?
The brain works as a system
- may parts are incorporated into the assessment of risk and reward
- to decide whether something is rewarding/risky we compare it to our past experiences
3 areas of the brain are important in our assessment of risk and reward.
What are these 3 areas?
- amygdala
- ventral striatum
- PFC
According to the Triadic Brain model, what is the amygdala involved in?
- when the amygdala is active, we feel fearful (something threatening is happening in the environment) → increases our response to risk
- when the amygdala isn’t active, no fear learning is happening and we feel calm and secure
- amygdala assesses FEAR vs. SAFETY
According to the Triadic Brain model, what is the ventral striatum involved in?
- when the VS is active, we are experiencing something rewarding
- when the VS isn’t active, nothing rewarding is happening in the environment and we feel boredom
According to the Triadic Brain model, what is the PFC involved in?
- assesses the signal to ensure an appropriate response is made to the context
- makes a cognitive assessment of our emotional response
- regulates the response in our amygdala and VS
When the amygdala and VS are firing highly, what are we doing?
We are performing a risky + rewarding behaviour
In relation to risk and reward, how does the brain develop with age?
- greater reactivity of reward centres
- decreased reactivity of threat centres
- less regulation
At which age are we most sensitive to reward and least sensitive to threat?
Adolescence
If we are sensitive to reward and not sensitive to threat, what are we more likely to do?
We are more likely to take risks
Connections from the PFC are weaker/stronger during adolescence.
Connections from the PFC are WEAKER during adolescence.
What is the result of weaker connections from the PFC in adolescence?
It means we are less able to regulate our behaviour → more likely to respond to things emotionally, rather than assess them cognitively
–> suggests decreased inhibition during adolescence, especially to rewarding stimuli
Why is the Triadic Brain model incorrect?
Adolescents also have increased responses to threat (amygdala), not just to rewards (VS) → the amygdala should be just as big as the VS on the diagram
Somerville et al. (2011) did a Go-No-Go task with happy faces and neutral faces.
What did this study involve?
Somerville et al. (2011):
Pps had to press a key when a neutral face appeared on a screen but NOT when a happy face appeared
Happy faces = social rewards
What did Somerville et al.’s (2011) study test?
Somerville et al.’s (2011) study tested pps’ ability to inhibit their prepotent response (key press to a happy face, i.e. social reward)
What did Somerville et al. (2011) find in their study?
There was no difference in the number of correct responses in children, adolescents or adults BUT adolescents were more likely to respond to no-go stimuli (happy faces)
- adolescents were less able to inhibit their response to a positive social reward
- this is associated with increased activity in the VS
Does Somerville et al.’s (2011) study support or disprove the Triadic Brain model?
Somerville et al.’s (2011) findings provide partial support for the Triadic Brain model
Who proposed an alternative model to the Triadic Brain model?
Casey et al. (2008)
What is the basis of Casey et al.’s (2008) model?
- different areas of the brain develop at different times
- the PFC develops linearly with age
- the VS develops faster and less linearly with age (peaks, then flattens in adulthood)
How does the linearly development of the PFC influence our cognition/behaviour?
The PFC develops linearly with age - this increases our ability to control things cognitively
Measuring ________ compounds risk and reward (because _______ involves risk and reward).
Measuring IMPULSIVITY compounds risk and reward (because IMPULSIVITY involves risk and reward).
Is Casey et al.’s (2008) correct?
Casey et al.’s (2008) model can’t be correct - it only takes reward into account and ignores risk
Who did a similar study as Somerville et al. (2008), but using fearful faces (= social threat) instead of happy faces?
Casey et al. (2008)
What did Casey et al.’s (2008) Go-No-Go study involve?
They used the same Go-No-Go paradigm as Somerville et al. but replaced happy faces (= social reward) with fearful faces (= social threat)
What did Casey et al.’s (2008) Go-No-Go study find?
They found the same pattern of increased false alarms in adolescents
- adolescents had an increased impulse to respond in threatening situations
→ suggests that previous models are too simple
Experience drives the connections between areas. This means that there will be stronger connections between controlling parts of the ___ than reactive parts of the ___.
Experience drives the connections between areas. This means that there will be stronger connections between controlling parts of the PFC than reactive parts of the VS.
Which researcher/s did a study investigating the effect of low-risk and high-risk gambles on brain activity?
van Leijenhorst et al. (2010)
What were van Leijenhorst et al. (2010) looking for?
They were looking for an inverted-U shaped response to reward and a linear response to cognitive control with age
Which model were van Leijenhorst et al. (2010) trying to test - the Triadic Brain model or Casey et al.’s (2008) model?
van Leijenhorst et al. (2010) were testing Casey et al.’s (2008) model
