Pre-adult brain development risk taking

• Name the brain regions that make up the limbic system

  • Amygdala
  • Ventral striatum
  • Nucleus accumbens
  • Develops during childhood and adolescence and helps process emotional experience and regulate emotions e.g. controlling impulsive behaviour
• Outline the role of the cerebral cortex

  • Most of thinking
  • Frontal cortex - executive functions e.g. abstract thinking
  • Auditory / visual cortex - sensory processing
  • Motor cortex - movement process
  • Does not reach full maturity until late adolescence where it takes full control of the limbic system
• Outline synaptogenesis

  • New synapses formed
  • Axons & dendrites grow towards each other to form networks
  • Before birth and continuous postnatally in exuberant synaptogenesis
  • More synapses = greater neurotransmitters = better cognitive processing
  • Continues by promoting flexibility as brains become less ‘fixed’ at birth and more open to alteration through experience and learning
• Outline myelination

  • Brain weight from birth increases at age 2 due to myelination
  • Rapid in first 2 years of life but continues into adolescence
• Outline synaptic pruning

  • Exuberant synaptogenesis follows genetically programmed plan to produce more than needed
  • Explains why twice as many neurones at age 3 compared to adult
  • After 3 years there is a period of synaptic loss ‘fine tuning structures’
  • Neurones used most often experience greater neurotransmitters activity & strengthened synapses and inactive ones are pruned
  • Organises brain so areas become specialised
• Outline how neuronal activity explains risk taking behaviour in adolescents

  • Synaptogenesis, pruning & myelination occur at different rates up to adolescence which affects behaviour and may be more likely to take risks
• Name examples of risk taking behaviour adolescents do

  • Binge drinking
  • Drugs
  • Unprotected sex
  • Still persists even if adolescents are educated - freewill, individual
• What did Willoughby find about risk taking behaviour in adolescents?

  Willoughby:

  • Found mortality rates increase in adolescence across Western cultures as do unintentional injuries
  • Many disabilities or deaths are preventable however often linked to risk taking behaviour such as substance abuse
  • More focus on biological explanations and role of brain development instead of social
• Outline Dual Systems Theory

  Steinberg:

  • Risk taking in adolescence directed by interaction of 2 brain systems maturing at different times

  Ventral striatum:

  • Emotion regulating, matures early adolecence
  • Changes due to increased dopamine activity
  • Includes nucleus accumbens that is sensitive to rewards in adolescence

  Prefrontal cortex:

  • Slower to develop, cognitive control system assesses risk
  • Undergoes synaptic pruning, matures in young adulthood
  • Matures later so cannot assert control over VS rewarding sensation seeking from risk
  • Imbalance only in adolescence = impulsive
• What did Johnston say about the ventral striatum and risk taking?

  Johnston:

  • Changes in ventral striatum almost exactly matched increase in arrests for criminal behaviour that peaks in mid to late adolescence
  • Sex difference - females peak at 16 and males at 19
• Outline the early effects of stress in risk taking behaviour

  • Evidence that early stressful experiences can predispose individuals to later risk taking behaviour by affecting brain development e.g. witnessing or experiencing abuse
• Outline how the brain develops

  • Develops in a ‘bottom up’ fashion
  • Primitive structures essential for survival develop first in lower brain
  • Advanced areas towards the front take longer and continue to develop into adolescence
• Outline Meyer & Bucci - Dual Systems Theory

  • Meyer & Bucci:
  • Lab experiment to mimic system imbalance in adult rats
  • Decreased activity in prefrontal cortex whilst increasing activity of the NA
  • Found rats took twice as long as a control to learn to inhibit a response to an expected reward (did not arrive)
  • Not normal of adult rats but matched earlier study of adolescent rats and supported casual effect between brain system imbalance and impulsive behaviour
• What did Romer find about early effects of stress?

  Romer:

  • More stress the child experiences the more likely they are to engage in risky behaviour in adolescence
• What did Kotch find about early effects of stress?

  Kotch:

  • Longitudinal study of children at risk of neglect
  • Found parental neglect of 2 year olds predicted aggressive behaviour at 8
  • No such effect when neglect occurred when children were over 2
  • Idea of critical period for development of relevant brain structures and once over the effects of stress are less damaging
• What did De Belis say about early effects of stress?

  De Bellis:

  • Suggests neurotransmitters & hormones released during stressful experiences may damage prefrontal cortex
  • This prevents the prefrontal cortex reaching full maturity and reduces moderation of influence on ventral striatum in adolescence so more risk taking
• What did Fareri & Tottenham say about effects of early stressful experiences?

  Fareri & Tottenham:

  • Early neglect causes lasting damage to amygdala and ventral striatum, both involved in regulating emotion