Lecture 16: Neurosciences of Stress Flashcards
what causes stress
an external trigger
what is anxiety
persistent, excessive worry that doesn’t go away even in the absence of a stressor
what does stress alter
the body’s equilibrium
what are the 2 types of stress
physical (injury, hunger, etc)
physchological (deadlines, pressure)
what is the Inverted U curve of stress
there is an optimal arousal level where we have optimal performance
if arousal is too low, we don’t have interest and pay less attention
if arousal is too high, performance is impaired
what is the relationship between stress and the difficulty of a task
Difficult tasks are performed better during low stress levels; easy tasks are performed better during moderately high stress levels
what are the 2 kinds of stress responses
Immediate response (SAM axis)
Slightly delayed response (HPA axis)
what is the Immediate response (SAM axis)
happens very quickly
amygdala activates it, sending distress signal to hypothalamus
Epinephrine and norepinephrine are released
what is the Slightly delayed response (HPA axis)
Hypothalamus releases CRH
Pituitary gland releases ACTH
Adrenal cortex releases cortisol
is the HPA axis is heavily connected to other parts of the brain
Prefrontal cortex (-), hippocampus (-), and amygdala (+)
what is the HPA Axis-Negative Feedback Loop
Normally, cortisol produced in the adrenal cortex inhibits the hypothalamus and pituitary gland
Negative feedback loop important for allostasis (homeostasis)
what happens in the body when were stressed
Increased heart rate and blood pressure, and faster, shallower breathing, increased availability of glucose
are Physical and psychological stressors are processed in the same brain circuits
they are processed in overlapping but different brain circuits
what 3 areas in the brain are active during stress
prefrontal cortex, brainstem, and limbic system
which axis do physical stressors use
Physical stressors mostly activate autonomic stress responses (SAM axis) for a faster response
which axis do psychological stressors use
HPA axis
what triggers the SAM axis
Locus coeruleus (LC)
what triggers the HPA axis
Paraventricular nucleus (PVN) of hypothalamus
what is the main integrator of stress signals
Paraventricular nucleus (PVN) of hypothalamu
what part of the brain is in charge when we are alert and in control
prefrontal cortex
what part of the brain is in charge during acute stress
high levels of norepinephrine and dopamine switch the control from the prefrontal cortex to the limbic system
what is the Impact of Acute Stress on Cognitive Function
detrimental effects of executive function
Activation of the sympathetic nervous system is linked to inflammation
how does chronic stress affect the HPA Axis-Negative Feedback Loop
the brain loses its ability to turn off the HPA axis, so its overactive
Chronic activation of the HPA axis can lead to cortisol resistance
what is Allostatic Overload
When environmental challenges exceed the ability to cope
An extreme state where stress responses are repeatedly activated
does chronic stress increase risks?
increase risk for disease and early mortality
what happens in the brain with chronic stress
Reduced dendritic complexity in the hippocampus and prefrontal cortex
Learning and memory deficits
Possible hypertrophy of the amygdala
how is stress associated with mental health
People with major depression have higher cortisol and smaller hippocampal volumes
Anxiety disorders are more common in those with early life stress
how can exercise help with stress
Exercise can downgrade the stress response
Mind body (yoga, etc) exercise may have a larger impact than other forms of exercise
why is mind-body exercise good for exercise
Activation of the parasympathetic system
Yoga decreases cortisol, heart rate, and blood pressure
what’s happening in the brain with mind-body exercise?
Increased gray matter volume in the insula and hippocampus
Increased activation in the prefrontal cortex
what does mindfulness do
has a moderate effect on anxiety
what does breath work do
Breathing exercises improved both anxiety and depression
what is Five-Finger Breathing
Place index finger and thumb on pinky finger of other hand
As you breathe in, trace up to the tip of your pinky and as you breath out, trace down your pinky
Repeat with each finger for 10 breaths
