Adolescent brain development & psychological functioning

Leah Somerville

Department of Psychology & Center for Brain Science Harvard University

Affective   Neuroscience   &   Development   Laboratory

HLS 2015

Studying brain development

• 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)

Concluding points

The adolescent brain is still developing

It is a ‘sponge’ for rewards and for learning

It needs to be treated with care - Avoid the explicitly negative inputs - Provide suite of expected inputs - Maximize positive influence

CAREER Award