Week 2

Question 1

Which axis do physical vs psychosocial stressors correspond with?

Answer 1

Physical stressors:
The sympatho-adrenal-medullary (SAM) axis

Psychosocial stressors:
The hypothalamus-pituitary-adrenal (HPA) axis

Question 2

What happens during the activation of the sympatho-adrenal-medullary (SAM) axis?

Answer 2

• first and fast response
• activation of the sympathetic branch, causing secretion of catecholamines (adrenalin and noradrenalin) (and suppression of the parasympathetic nervous system)
• increase in heart rate, blood pressure and respiration frequency

Question 3

What happens during the activation of the hypothalamus-pituitary-adrenal (HPA) axis

Answer 3

• longer lasting effects in the body
• activation of the HPA axis, causing secretion of cortisol
• metabolic effects, mobilisation of energy, increased production of catecholamines

Question 4

What happens in the brain during physical stressors (e.g. pain)?

Answer 4

• they require an immediate body response involving the activation of the brainstem and hypothalamus
• rapid activation of the autonomic nervous system and HPA axis

Question 5

What happens in the brain during psychosocial stressors?

Answer 5

• evaluated and processed in the frontal lobes and thalamus
• trigger stress responses via the prefrontal cortex with the limbic structures
• projects to the hypothalamus which activates the HPA axis

Question 6

What are the two loops in which our brain will process threatening stimuli?

Answer 6

• fast (subcortical)
• slow (cortical)

Question 7

What is the Fast (subcortical) loop?

Answer 7

• shortcut from the lateral geniculate nucleus of the thalamus directly to the amygdala
• stimulus identified as threatening = autonomic nervous system activation

Question 8

What is the Slow (cortical) loop?

Answer 8

• information from the visual cortex is more accurate
• the visual cortex tells the amygdala that the stimulus is dangerous = autonomic nervous system is kept activated
• the visual cortex tells the amygdala that the stimulus is not dangerous = autonomic nervous system is inhibited

Question 9

What does the brain (specifically the hypothalamus) do when it identifies a threat?

Answer 9

1) The paraventricular nucleus of the hypothalamus releases a polypeptide triggering the fight-or-flight response.

2) The CRH released stimulates the anterior pituitary to produce and secrete ACTH-adrenocorticotropic hormone. This stimulates the adrenal cortex to secrete cortisol, subsequently exerting a number of effects in the body, preparing it even further for a fight-or-flight response.

Question 10

Which two systems can the immune system be divided into?

Answer 10

1) Innate immunity (= sub-system of the immune system which is genetically programmed to detect invariant features of invading microbes; include dendritic cells (DCs), macrophages, and neutrophils, and others)

2) Adaptive immunity (= highly specific immune responses, generation of an immunological memory after an initial response to a specific pathogen; composed of T and B lymphocytes)

Question 11

What proteins have been associated with depressive symptoms?

Which effect does stress have on them?

Answer 11

Cytokines

Stress alters the profile of cytokines produced by the different helper T-cells which regulate immune responses to intracellular and extracellular pathogens, leading to a decreased ability to fight infectious disease, whilst increasing the risk of allergic responses

Question 12

What are the effects of different kinds of stressors on the immune system?

Answer 12

chronic stressors: suppression of the immune function

acute stressors: upregulation of natural immunity and downregulation of some functions of specific, adaptive immunity

brief naturalistic stressors: changes in the profile of cytokines produced by the different helper T-cells, which regulate immune responses to intracellular and extracellular pathogens

stressful event sequences: varied according to event

subjective stress: no association with immune function measures

Question 13

What is Heart rate variability?

Answer 13

HRV reflects the ability of the heart to adapt itself to fluctuations, for example, in blood pressure and respiration. It is also associated with the ability to control autonomic responses.

Question 14

Describe low and high HRV.

Answer 14

Low HRV:

*associated with a number of psychopathological states (anxiety)

High HRV:

• associated with flexible and adaptive top-down and bottom-up cognitive processing
• self-regulatory strength and reduced negative emotion during acute stress

Question 15

What type of biomarker is HRV?

What has HRV more recently been used as?

Answer 15

a vagal nerve-mediated biomarker of cardiac function

a psychophysiological measure to investigate the effect of attention-regulation processes

Question 16

What are the findings with regards to HRV and mindfulness?

Answer 16

• Not all meditations have been associated with an increase in HF-HRV.
• Not all populations respond similarly to mindfulness with regards to HRV.

Question 17

What is Sensory information filtering or sensory gating?

Answer 17

Sensory information filtering or sensory gating refers to the attenuation of neural responses to repeated stimuli.

Question 18

What is Prepulse inhibition (PPI)?

Answer 18

reduction of the startle response to a strong sensory stimulus (pulse) when the presentation of this strong stimulus is preceded by a weak stimulus (prepulse)

Question 19

What is acoustic startle reflex (ASR)?

Answer 19

• a contraction of the skeletal musculature when an intensive acoustic stimulus is presented
• normally concerns contraction of the orbicularis oculi muscle