Neurodevelopment Flashcards
Steinberg et al. (2013)
Why?
unintentional drownings and self-inflicted injuries increase in adolescence, peak continues until just before the 20s
Lenroot et al. (2007)
Brain volume is 95% its total size by age 6.
Boys have larger brains than girls by an average of 8-10%.
Could think that boys are taller and so a bigger brain is consistent, but actually from ages 10-13.5 girls tend to be slightly taller than boys. Also for the first 15 years, the cumalative mean height for both sexes is within 1% of each other, with girls being slightly taller.
Gogtay et al. (2004)
Between 10-15 start to grey matter is thinning, there is less grey matter over the adolescence period.
This starts in the sensory cortices, followed by the visual cortices, motor cortices, before finalising its trajectory in the frontal cortices. This means the PFC seems to be achieving equivalent levels much later in adolescence.
Different areas of the brain show different trajectories,. This shows that the brain is undergoing massive resorganisation during puberty.
Winkler et al. (2009)
Use to criticise the differences of neuroimaging.
volume-based vs surface-based - different algorithms, different result. Not simple, what happens with voxels that aren’t completely gry or white?
MRI is very good, can go in vivo and look how the brain structure develops over time, but still has issues. E.g. resolution, correlational data, indirect measures.
Use vogrey matter volume to look at development of subcortical structures
Ostby et al. (2009)
Cerebral cortex in general declines, in a region specific manner.
Amygdala is a set of nuclei responsible for coding the emotional valence of things, and influencing our approach/avoidance response, fear conditioning. This sees an increase in grey matter volume over adolescence.
Caudate nucleus and nucleus accumbens are parts of the reward system of the brain, dopaminergic structures. Respond to rewarding stimuli in the environment. These structures show a decrease in grey matter over adolescence.
Ernst (2014)
Greater neuroplasticity in childhood
Hare et al. (2008)
Structure-function relationship.
Emotional go/no-go task. See fearful and neutral faces, have to respond to the fearful faces by pressing a button, but control the impulse to push this button when neutral faces show. Programmed so fearful faces appear 70% of the time compared to neutral at 30% of the time. Create an almost prepotent response to pressing the button.
Found that adolescents had less inhibitory control, had poorer ability to withold a response.
Also have a really ehance response of the amygdala (emotional centre).
neurophysiological mechanism that has big implications for adolescent behaviour, their tendency to be impulsive towards emotional stimuli.
Qu et al. (2015)
BART task.
This is a measure of risk taking tendencies, involves inflating a balloon to win money. The larger they inflate the balloon the more money they make, but the more risk the balloon will pop and they will lose their money.
Measured adolescents at 2 time periods, 15 y/o and 17 y/o. Striatum becomes less engaged which correlates to a reduced tendency to over-inflate the balloon.
Maturing of the reward system means less sensitive to reward, reflected in less risky behaviour.
Developmental structural trajectories reflected in greater brain function which reflect in certain aspects of behaviour.
Schulman et al. (2016)
Sternberg (2005)
Early developing socioemotional-incentive processing system vs an immature cognitive control system. Results in increased motivation to persue rewards and reduced control over impulses.
starting an engine but not having a skilled driver behind the wheel.
Steinberg (2008)
Dual systems model
Slowly developing cognitive control system, socioemotional system follows an inverted U shape, increasing and peaking in mid-adolescence
Casey et al. (2008)
Maturational imbalance model
Slowly developing cognitive control, socioemotional system shows increase in arousibility until mid-adolescence where it plateaus and remains at this level until adulthood. Strengthening cognitive control system causes SE to become less arousable.
Luna and Wright (2015)
Drive dual system
socioemotional system shows an inverted U shape pattern over adolescence, but cognitive control peaks and plateaus during mid adolescence
Ernst (2014)
Triadic model
seperate out socioemotional system into emotional intensity (amygdala), impulsivity (striatum) and regulatory control (PFC).
When these balance we see ideal behaviour, but any imbalances cause behaviour typical of adolescence, e.g. overactivation of amygdala with less inhibitory control, could see greater emotionality.
Greater reward seeking could be independent of emotional responsivity.
Steinberg et al. (2009)
psychosocial maturity.
Decoupling of general intelligence and behaviour in the social domain.
Adolescents are not behaving like this bc they are stupid.
Developed an index of psychosocial maturity by measuring how aware adolescents are of the social consequences of their actions. Self-report, higher scores indicate more adult like behaviour and responsibility.
Intelligence tested using the Weschler Intelligence scale, showed intelligence is increasing linearly over age and is becoming comparable to adults. Psychosocial maturity is lagging behind which is why we might be seeing some of the characteristic behaviours.
Paus (2010)
Increases of white matter (and reduction of grey matter) density may reflect developments in axonal calibre and integrity.
MRI measures the response of hydrogen atoms in the fat in the myelin of axons. If the diameter of the axon is increasing this may cause the reduction of surrounding grey matter but will not be reflected in the fat. Which is why MRI might not show increases in white matter cause reduction in grey matter.
Better white matter integrity means better communication.
