Test 1 Part 2 Flashcards
Which axis mitigates the physiological response to stress
HPA
____ is released by the hypothalamus. Two functions
CRH/CRF. It is part of the HPA signalling system and ultimately causes the adrenal glands to secrete glucocorticoids, but it also plays a role in the extrahypothalamic tract. (acts as a DA and Glu modulator in the Nacc)
What specific area of the hypothalamus secretes CRF/CRH
periventricular nucleus of the hypothalamus.
Explain the negative feedback loop in the HPA axis. What area of the brain is positively activated by the HPA axis products?
the glucocorticoid can mobilize our energy sources in times of stress but can also feedback into the HPA axis, and has an inhibitory action on the pituitary and hypothalamus.
on the contrary, the amygdala is positively regulated by glucocorticoids. The BNST gets activated, and is responsible for emotional learning.
Allostatic load
the process of adaptation to acute stress, involving the output of stress hormones which act in the ways to restore homeostasis in the face of challenge. LOAD is the cost to the body from excessive stress response activation
T/F allostatic load can be measured physically
true. BP, waist hip ratio, serum HPL, blood plasma levels.
Factors that affect allostatic load
1) interpretation of the event
2) differences in cardiovascuar activity
3) body fitness
4) personal behaviours (smoking, etOH intake etc).
paradox of stress repsonse
in short term, stress response is effective, but chronic response activation is damaging– will dysregulate brain circuitry and cause physiological stress and disease. Drugs of abuse activate the stress system. CRF was upregulated in the HPA axis and triggered by EtOH. BUT EtOH decreases amygdala activation that occurs upon activation of the HPA axis
this removes the emotional reponse to stress, but you are still stressed.
Hedonic dysregulation
is the emergence of a prolonged a negative mood state, resulting in the lack of feelings of hedonia, or pleasure. This dysregulation is a measure of allostasis, in which a non-homeostatic set point is maintained by the body, and is often used to explain drug addiction.
QUESTION: Hedonic dysregulation theory
Theory poses that the main driving force behind drug use is to reduce the negative mood state that is produced after the drug has been taken (depression, irritability, anxiety).
QUESTION: Hedonic dysregulation theory
Theory poses that the main driving force behind drug use is to reduce the negative mood state that is produced after the drug has been taken (depression, irritability, anxiety).
The negative emotional state that drives such negative reinforcement is hypothesized to derive from dysregulation of key neurochemical elements involved in reward and stress within basal forebrain structures, including the ventral striatum and extended amygdala.
QUESTION: describe the escalation procedure. Describe an experimental result that indicates the effect of escalation on hedonic dysregulation.
A method of establishing cocaine/drug addiction in an animal model that involves giving the animal long access to cocaine.
Rats that had long-term access to cocaine self-administered (ICSS) cocaine to a higher degree than a short-access group.
REFLECTS LOSS OF CONTROL?
- Withdrawal was then assessed.
- Electrode put in box. Defensive behaviours were measured (ie/ defensive burying). Long-term access rats spent more time engaging in defensive burying—ANXIETY AND IRRITABILITY AKA B PROCESS AKA NEGATIVE MOOD STATE which is part of hedonic dysregulation.
- There was also an INCREASE IN REWARD THRESHOLD: Long term access rats needed higher amounts of cocaine/stimulation to overcome a negative mood state (to stop defensive burying)
- Therefore, rats who were part of the cocaine escalation group increased in self administration, irritability, and had a higher ICSS threshold.
QUESTION:
Describe three patterns of exposure to stressors that may produce allostasis (2 points for each).
i) CHRONIC STRESS: also known as repeated hits ( SEE GRAPH) . Having the body experience a recurrent stress response because there is a constant experience of stressors such as life challenges (unemployment, violence, war etc). Experiencing life stress will activate the HPA system resulting in glucocorticoid/cortisol secretion, but AT A HARMFUL CONSTANT RATE.
a. Cortisol and stress response chronic activation puts the body in allostasis, making it function at a different set point for a long time, which can cause negative health outcomes like earlier aging, mental health problems, METABOLIC PROBLEMS etc.
II) Lack of adaptation: the failure to habituate to repeated stressors of the SAME KIND (not necessarily like repeated hits, which multiple stressors can be of cause hence inadapatability). Instead, the same stressor is encountered repeatedly, and the person is not able to adapt to it.
a. Usually, after a few experiences, individuals would put coping mechanism in place to reduce stress response. BUT: if there is a lack of adaptation, the physiological stress response continues at a HIGH MAGNITUDE.
i. Ex/ public speaking phobia. People do not practice it and thus do not learn how to cope with it. This makes an unnecessary stress response each time a presentation is assigned.
i) Prolonged response: failure to turn off each stress response efficiently, EVEN AFTER THE ACTUAL EXPERIENCE/SCENARIO IS REMOVED.
a. Abnormal recovery: they do not efficiently return to physiological basaeline after the stressor is gone.
i. EX/ cortisol levels are elevated in the evening in people who are sleep deprived (lololol).
ii. Will result in allostatic load/ negative manifestations of `change in homeostatic set point.
QUESTION:
Describe three patterns of exposure to stressors that may produce allostasis (2 points for each).
i) CHRONIC STRESS: also known as repeated hits ( SEE GRAPH) . Having the body experience a recurrent stress response because there is a constant experience of stressors such as life challenges (unemployment, violence, war etc). Experiencing life stress will activate the HPA system resulting in glucocorticoid/cortisol secretion, but AT A HARMFUL CONSTANT RATE.
a. Cortisol and stress response chronic activation puts the body in allostasis, making it function at a different set point for a long time, which can cause negative health outcomes like earlier aging, mental health problems, METABOLIC PROBLEMS etc.
II) Lack of adaptation: the failure to habituate to repeated stressors of the SAME KIND (not necessarily like repeated hits, which multiple stressors can be of cause hence inadapatability). Instead, the same stressor is encountered repeatedly, and the person is not able to adapt to it.
a. Usually, after a few experiences, individuals would put coping mechanism in place to reduce stress response. BUT: if there is a lack of adaptation, the physiological stress response continues at a HIGH MAGNITUDE.
i. Ex/ public speaking phobia. People do not practice it and thus do not learn how to cope with it. This makes an unnecessary stress response each time a presentation is assigned.
i) Prolonged response: failure to turn off each stress response efficiently, EVEN AFTER THE ACTUAL EXPERIENCE/SCENARIO IS REMOVED.
a. Abnormal recovery: they do not efficiently return to physiological basaeline after the stressor is gone.
i. EX/ cortisol levels are elevated in the evening in people who are sleep deprived (lololol).
- Will result in allostatic load/ negative manifestations of `change in homeostatic set point.
Opponent Process
persistent drug use should produce a compensatory adaptation in the system in the opposite direction. This B process serves to help restore homeostasis. This B compensatory reaction to offset drug effects (ex/ pain sensitivity, increase HR in order to counteract opioid)
If you keep taking, due to conditioning responses, there is a predictive quality, and the compensatory response becomes stronger stronger.
