The Effects of Stress And The Brain

1. Understanding the Impact of Stress
on Brain Development and Learning

2. Merriam-Webster define stress as:
A physical, chemical or emotional factor that
causes bodily or mental tension

3. Acute stress is general short-term with a
clearly defined beginning and end
Chronic stress is long-term and prolonged
stress with no clear ending
Both acute and chronic stress trigger the
physiological stress response

4. Triggering of the sympathetic nervous system
which prepares the body to deal with
perceived threat by:
◦Increase of heart rate and blood pressure
◦Increase of cortisol –“stress” hormone which has
anti-inflammatory and immunosuppressive
properties
◦Decline of parasympathetic activity which regulates
“automatic” bodily functions and maintains
homestasis

6. ◦Shorter form of
the serotonin
transporter is
associated with
vulnerability to
increased
response to
stress by
developing
depressive
illness and
alcoholism

7. ◦An allele of the monoamine oxidase A gene result
in more vulnerability to abuse in childhood,
increased risk of becoming an abuser & show
antisocial behaviors.

8. Early abuse can result in life long emotional
reactivity and stress hormone reactivity –
both associated with cognitive decline and
shorter lifespan in animal studies

9. Stress reduction in infants can be influenced
by maternal bonding through a variety of
factors
◦Physical proximity
◦Modeling
Early patterns “hard-wire” the stress
response –critical period during 1
st
nine
months

10. Males most typically mirror the fight or flight
response
Females engage fight or flight AND befriend

11. There is an inverted relationship between
learning and levels of cortisol
During acute stress, higher levels of cortisol
result in:
◦Enhanced immunity
◦Enhanced memory
During chronic or prolonged stress,
the increased levels of cortisol result
in:
◦lower immune response
◦Impaired cognitive functioning

12. The Hippocampus is
the brain structure
primarily responsible
for learning and
memory
The Hippocampus is
highly sensitive and
malleable
Cortisol decreases
and retracts the
dendritic growth in
the hippocampal area

13. Within the Hippocampus, is the dentate gyrus,
a structure which seems to play a role in the
memory of sequences of events
It has high plasticity and is constantly
producing new neurons, even throughout
adult life.
Certain types of stress suppress neurogenesis
and cell survival in the dentate gyrus

14. Cortisol inhibits long-
term potentiation –cell
sensitivity in
communication
Adolescent brain is more
receptive to long-term
potentiation without
interference

15. Repeated or chronic stress causes dendritic
shortening in the medial prefrontal cortex
The results in impairment in attention set
shifting

16. Both acute and chronic stress produce
dendritic growth in neurons in the amygdala.
The results of include:
◦Increases anxiety
◦Increased aggression

17. In animal research, chronic stress causes
atrophy of neurons in the hippocampus and
prefrontal cortex
and
Hypertrophy of neurons in the amygdala
Results:
◦Decreased learning and memory
◦Increased anxiety and aggression

18. The results from
animal studies are
mirrored in humans
through a loss of
hippocampalvolume
and an increase in
amygdalavolume in
MRI studies
PET scans also
demonstrate altered
patterns of activity in
the related brain areas
during stress

19. Learn stress
management –variety
of techniques
Problem-focused –
changing the stressor
Emotion focused –
changes our response
to the stressor

20. Physical
Cognitive
Emotional
Behavioral

21. Physical Techniques:
Exercise Meditation
Relaxation

22. Cognitive Techniques:
Social Comparisons Re-Evaluation
Distraction

23. Emotional Techniques:
Social Support Release
Laughter

24. Behavioral Techniques:
Helping Others

25. Optimism is associated with lower cortisol
production and higher heart rate variability
(showing higher parasympathetic activity)
Optimistic people are, on average, healthier
and live longer than pessimistic people
Optimistic people have higher levels of life
satisfaction

26. Poor self-esteem has
debilitating effects:
◦Increased levels of cortisol
◦Inability to regulate cortisol
levels under stress
◦12-13% loss of hippocampal
volume

27. Improve sleep quality and quantity
Have a good social support system
Maintain a positive outlook on life
Maintain a healthy diet
Avoid smoking
Regularly exercise –moderate activity
Build positive self-esteem
Learn successful stress management

28. McEwen, B.S. Protective and damaging effects
of stress mediators: central role of the brain.
New England Journal of Medicine. 1998, 338:
171-179

29. Q & A
Robin Donaldson,
[email protected]