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Adolescent brain development & psychological functioning
Leah Somerville
Department of Psychology & Center for Brain Science Harvard University
Affective Neuroscience & Development Laboratory
HLS 2015
• The adolescent brain is different from the adult brain.
Lessons learned about the adolescent brain
The adolescent brain is different from the adult brain
Gray Matter: Computation CentersWhite Matter: Connection Pathways
Brain Dev Cooperative Group (2013)
The gross structure of the adolescent brain is less metabolically efficient and less integrated
than the adult brain.
Mills et al. (2014)
The prefrontal cortex is critical for planning,
decision making, and self-control.
The prefrontal cortex is continuing to develop well
past age 18.
The adolescent brain is different from the adult brain
• The adolescent brain is different from the adult brain.
• The maturational state of the adolescent brain ‘tunes’ it to rewards and learning opportunities.
Lessons learned about the adolescent brain
The adolescent brain is tuned to rewards and learning opportunities.
Dopamine
Dopamine pathways
Replotted from Andersen et al (2000)
Dop
amin
e Re
cept
or D
ensit
y
0
30
60
90
120
Age (days)20 40 60 80 100
Dopamine, the “currency” of rewards and
learning in the brain, is uniquely
potent during adolescence.
Galvan et al., 2006
Adolescents > Children & Adults
Striatum Signaling “registering” learning opportunities
Cohen et al., 2010
Arbitrary Cue
The adolescent brain is tuned to rewards and learning opportunities.
The adolescent brain is tuned to rewards and learning opportunities.
Adolescents rely on learning from direct
experience more than adults, and outperform adults in experience-
based learning.
% ti
me
rew
ard
foun
d
20
30
40
50
60
70
Time —>1 2 3 4 5 6
Adults Adolescents
Replotted from Decker et al (2015)
False Instruction
• The adolescent brain is different from the adult brain.
• The maturational state of the adolescent brain ‘tunes’ it to rewards and learning opportunities.
• Neurodevelopmental trajectories are molded by the environment.
Lessons learned about the adolescent brain
Neurodevelopmental trajectories are molded by the environment.
Sheridan et al, 2012
Institution Typical env. Institution Typical env.
Adverse environments impact brain health
8-11 year olds
Deprived environments hijack neurodevelopment.
“Moving parts get broken”
Neurodevelopmental trajectories are molded by the environment.
Hippocampus
Prefrontal cortex
Adversity at age
3-5
Adversity at age 14-16
Negative
impact
Negative
impact
Andersen et al., (2008)
“Moving parts get broken”
Neurodevelopmental trajectories are molded by the environment.
Hippocampus
Prefrontal cortex
Adversity at age
3-5
Adversity at age 14-16
Negative
impact
Negative
impact
Andersen et al., (2008)
The developmental trajectory of PFC is tenuous during adolescence.
“Moving parts get broken”
Neurodevelopmental trajectories are molded by the environment.
Hippocampus
Prefrontal cortex
Adversity at age
3-5
Adversity at age 14-16
Negative
impact
Negative
impact
Andersen et al., (2008)
These effects are not temporary.
Neurodevelopmental trajectories are molded by the environment.
Social & identity development - modeling peers
Stress - deprivation - violence - chaos
Learning opportunities
Nelson et al. (2005); Crone & Dahl (2012); Somerville (2014); Casey (2015)