Final Exam

Question 1

Describe HPA Axis

Answer 1

HPA AXIS: hormonal stress response system:
Hypothalamus, pituitary gland, adrenal gland
CRH (corticotropin releasing hormone) is released which binds to hypothalamus, hypothalamus releases ACTH (adrenocorticotropic hormone) which binds to adrenal gland, then adrenal gland releases cortisol
This isn’t a very fast system, takes about 15 minutes for the cells in the body to react to the cortisol

Question 2

What down regulates the HPA Axis system?

Answer 2

Hippocampus

Question 3

What are the types of glucocorticoid receptors?

Answer 3

○ Mineralocorticoid receptors (type 1) are used for everyday metabolic processes like blood pressure -- respond to low levels of cortisol
Glucocorticoid receptors (type 2) respond to a high level of cortisol because they have a low affinity

Question 4

Who is Walter Cannon?

Answer 4

Walter Cannon came up with a lot of the things we’re studying in this class, came up with terms homeostasis and fight or flight response, all stressors cause the same response

Question 5

Hans Selye stress theory

Answer 5

General adaptation syndrome: alarm phase, resistance phase, exhaustion phase
The exhaustion phase is incorrect, the pathology doesn’t have to do with “running out” of energy or neurotransmitters

Question 6

Bruce McEwen Stress Theory

Answer 6

Allostasis

Question 7

What makes things stressful?

Answer 7

Perceived lack of control and perceived lack of predictability

Question 8

What is the allostatic stress model?

Answer 8

○ Prediction of future threats is incredibly important
○ Also about balancing various ranges
○ Homeostasis on steroids: finite amount of energy that you’re going to move around to deal with threats
○ The way that mammals especially have evolved to deal with the complexity of the world, is through a brain that can be predictive, which can mobilize responses before the threat is actually there

Question 9

Describe sympathetic and parasympathetic nervous system

Answer 9

§ Sympathetic: innervation
□ Energetic, deployment of energy reserves, which is now going to be used up in responding to this threat
□ Acetylcholine released at the preganglionic fibers (very short), norepinephrine is released at the postganglionic fibers
□ Adrenergic receptors are present in something like a heart (some sort of organ), which will respond to norepinephrine
§ Parasympathetic: rest/digest is a quick way to describe it
□ Much less organized than the sympathetic, no chain ganglia, some ganglia come out of the brain stem while some come out of the pelvis
□ Preganglionic fibers are very long in this case, which also respond to acetylcholine
□ Postganglionic fibers are short in this case, also uses acetylcholine which binds to the muscle

Question 10

How is the HPA Axis system down regulated?

Answer 10

Glucocorticoids released by the adrenal cortex build up, and turn down the response due to receptors in the hippocampus, which have the highest density of glucocorticoid receptors, which then shuts off the pathway

Question 11

What is the master gland of stress?

Answer 11

The brain: we are capable of suppressing the physical response

Question 12

Describe positivity offset

Answer 12

under no threat, organisms have to be curious. Under conditions of threat, if there’s any hint of them, there’s a negativity bias: the threat weighs very heavily on the brain

Question 13

What is the inverted U?

Answer 13

• The Inverted U: this is an incredibly important concept
○ Stress is not inherently a bad thing: we need it, to respond to stuff and to be motivated
We know how to remove stress, but it isn’t the inherent problem: when it becomes a pathology, where you are constantly on the very right end of the U

Question 14

Is stress adaptive or maladaptive?

Answer 14

• Is stress adaptive or maladaptive? It really depends
○ What task/situation is the individual in?
○ What is the particular context?
○ Individual variability in skill, preparation, experience
○ The time scale: short term or long term outcomes?
○ The criteria used to determine good or bad
§ Stress responses, self report, performance, coping strategies
○ Availability of alternative responses

Question 15

Describe LTP and LTD

Answer 15

○ LTP: same input results in a higher output over time, partially done through changes in receptors (more), but also could be changes in the amount of synaptic vesicles/neurotransmitters that are released
LTD: same story but the reverse effect, where the same input results to a lower output

Question 16

Discuss NMDA receptors

Answer 16

• Basic neurophysiology: NMDA receptors
○ Glutamate is the primary excitatory neurotransmitters
Glutamate system is one of the primary reasons that apoptosis/necrosis happens: too much glutamate causes excitotoxicity, which is overcharging a given neuron to the point where it can’t really do anything anymore

Question 17

Describe the startle response and how it happens

Answer 17

○ There’s two pathways from the visual cortex: one has many layers and ends up in the amygdala, while another goes very quickly to the amygdala
○ You might not even necessarily be away of what you’re responding to (image of spider flashing on screen where you can barely see it)
○ It’s the fastest response we can get – the startle response
§ Pretty much the same across the board for mammals
○ The amygdala decides that basically everything is a threat – err on the side of caution

Question 18

Is the amygdala all about fear?

Answer 18

○ The amygdala isn’t the fear center of the brain – it increases overall emotional activity
○ Think of it as a volume switch – either more reactive or less reactive
○ It’s a hub, not just one thing – the primary job is to react very fast to latent information
○ The prefrontal cortex “tunes” the amygdala through projections
○ Also, the more stressed you initially are, the more likely you are to have a strong reaction to a possible threat

Question 19

Describe how/where chronic stress causes neural remodeling

Answer 19

○ Under conditions of chronic stress, amygdala neurons become larger and more interconnected
§ This is technically safer, it’s a defensive move
The hippocampal and prefrontal cortex neurons atrophy significantly

Question 20

What’s happening when someone is in pain?

Answer 20

• What’s happening in the context of pain?
○ Damaged tissue, information is passed up through the spinal cord
○ However, first thing that happens is a reflex
○ There isn’t one part of the brain where everything comes together, it’s distributed to a bunch of different areas (memory, attention,
• Parallel processing: damage is conveyed through at least 4 different neurons -> large and small fibers
○ C fibers are partially responsible for pain information
○ Beta fibers are for mechanoreceptors, things like cutting
○ Delta fibers are associated with temperature, so pain from burning
Alpha fibers: proprioceptors of skeletal muscle

Question 21

How does stress analgesia occur?

Answer 21

• Stress analgesia: you don’t notice that you’re in horrendous pain when you’re in a situation that you need to be functional
○ Periaqueductal grey and hypothalamus are involved, where specific things are released and the sensory component isn’t received

Question 22

Describe attentional and emotional modulation

Answer 22

• Attentional modulation: if you’re distracted from the pain, the intensity and unpleasantness of the pain (rated from 1-10) is slightly less than if you’re focusing on the region of pain
  
  • There’s also emotional modulation: if you’re in a good mood, the intensity was really just barely lower, but the unpleasantness of it is considerably better than if you’re in a bad mood

Question 23

Is pain super dependent upon context?

Answer 23

○ Different descriptions of the situation: “you have to resist as long as you can” versus “the more you resist, the larger the benefit”
§ Same task, but different context going in -> 9/10 versus 5/6
§ What’s the goal? What’s the motivational context?
○ Different description of the situation: “moderate pain is worse than no pain”, versus “moderate pain is better than severe pain”
○ Remember, pain is an emotion

Question 24

Describe the connection between motivation and pleasure

Answer 24

• Being hungry:
○ Initiating food procurement/foraging, appetitive phase, dominated by wanting
○ Engaging with consumption, consummatory phase, dominated by liking
○ Satiation, strong learning, satiety phase -> the pleasure drops off dramatically
Motivation is dictating the level of pleasure

Question 25

How bad is social stress really?

Answer 25

Really bad:
• Mice experiment with a constant state of social instability
○ Comparison with mice that were shocked
○ No matter what they did, the social instability with “bully” mice led to a much higher mortality rate, 90% versus 10%
And:
• Effects of chronic social isolation, versus pair housed animals
○ What happens when you do 7 minutes of cardiac arrest on these mice, before restarting their hearts?
○ In the hippocampus, there’s a ton more cell death in the animals that were isolated
§ Most sensitive part of the brain to ischemic damage
○ It doesn’t matter what sort of other stressors you do, you never see anything to this level
○ After this, the isolated animals basically had no hippocampus left

Question 26

Why do we live in social groups?

Answer 26

○ When the benefits of living together outweigh the costs of living alone, animals tend to form groups
○ Costs for social species across the board (automatic)
§ Increased competition for resources
§ Increased likelihood of disease transmission
§ More conspicuous to predators
§ Increased probability of losing offspring due to intra-species killing
○ Benefits to group living (not automatic)
§ Susceptibility to predation may be reduced
□ Aggressive group defense, using group as a cover, increased vigilance in large groups
§ Increased efficiency in food gathering
□ Cooperative effort results in lions being able to take down large prey
§ Extreme localization of non-food resources
□ Breeding sites, sleeping locations

Question 27

Why are our brains so complicated and big?

Answer 27

§ Recognizing subtle emotions is a vastly complex computational problem that the world’s best supercomputers can’t do
§ But our brains have evolved to be able to do this, so it’s automatic for us

Question 28

What is the motivating factor in social situations?

Answer 28

Loneliness

Question 29

Describe the vole study with the nucleus accumbens and oxytocin

Answer 29

• Two very similar vole species: montane vole is highly polygynous, and prairie vole which is socially monogamous
○ High density of oxytocin receptors in nucleus accumbens in the prairie vole: very rewarding to have a tight social connection with one animal
○ The montane vole has oxytocin receptors too, just in a different place
○ If you overexpress oxytocin receptors in the accumbens in the montane vole, it will start to act like the prairie vole

Question 30

Describe cytokines

Answer 30

broad and loose category of small proteins that are important in cell signaling
§ Think of them as neurotransmitters of the immune system
§ However, they’re not just limited to the immune system

Question 31

Describe interleukins

Answer 31

multifunctional cytokines that are produced by a variety of lymphoid and nonlymphoid cells and whose effects occur at least partly within the lymphopoietic system

Question 32

Describe toll-like receptors

Answer 32

class of proteins that function as a type of pattern recognition receptor, and recognize molecules that are broadly shared by pathogens but distinguishable from host molecules, collectively referred to as a pathogen-associated molecular patterns (PAMPs)

Question 33

Describe antigens

Answer 33

substance that causes your immune system to produce antibodies against it

Question 34

Describe antibodies

Answer 34

protein produced by the immune system when it detects antigens

Question 35

Describe the body’s innate immune defense system

Answer 35

○ Surface barriers, with skin and mucous membranes
○ Internal defenses: phagocytes, fever, natural killer cells, antimicrobial proteins, inflammation
When we talk about getting sick, we’re talking about the innate response - standard inflammatory response

Question 36

Describe the adaptive immune response components

Answer 36

○ Humoral immunity (B cells, involved with blood, making antibodies, free-floating in the circulation), and cellular immunity (T cells, the fact that T cells need to come into contact)
○ High specificity and diversity, has a memory where subsequent exposure to the same agent induces an amplified response
○ It just takes time, about 14 days for the level of antibodies to build up in your system
○ Antibody-mediated immunity (AMI)
§ Involves B lymphocytes, plasma cells, and antibodies
○ Cell mediated immunity (CMI)
§ Involves T lymphocytes, antigen-presenting cells and MHC (major histocompatibility complex) molecules
§ Cellular immunity
§ Induction of apoptosis, complement proteins which poke holes in the infected tissue, does everything it can to kill the cell

Question 37

Describe how astrocytes work in immunity

Answer 37

○ Most common cells in the body, providing the scaffolding and support structure of the brain
○ They also play a huge role in immune function
○ Forms/maintains the blood brain barrier, basement membrane
○ Neurotransmitter sink: soaks up glutamate, protecting against excitotoxicity
○ Immune function:
§ Astrogliosis: creating a scar which acts as a second BBB, walling off the source of infection

Question 38

Describe how microglia function in immunity

Answer 38

○ Phagocytosis and scavenging - not particularly good at it though
○ Cytokine production
○ Immune receptors: Toll-like and cytokine
○ After interacting with cytokines, they completely change their structure, become reactive, and are able to move through the brain to the source of infection
○ Interaction with astrocytes: activation/modulation
Tight regulation of microglial response is necessary

Question 39

Describe the behavioral sickness response

Answer 39

○ Lethargy, nausea, anhedonia (things you generally like you have no interest in, you don’t want to do things that sound fun)
○ This is entirely brain mediated: the virus doesn’t want this
○ The reason it does this is to give the immune system more energy to do its thing
○ Motivation: immune system is conducting info that you’re infected, and a huge response is coming from the brain

Question 40

How does the brain communicate with the immune system?

Answer 40

The vagus nerve afferents, which has connection to every type of tissue of interest, extremely complicated

Question 41

How can one simulate a sickness response?

Answer 41

You can simulate a sickness response by injecting interleukin 1 beta into the brain, suggesting that that’s what’s mediating the sickness response

Question 42

What is an emotion?

Answer 42

§ Evolutionarily well conserved
§ Coordinated set of physiological and behavioral responses to something
§ The something differs as a function of species
§ Processed at many levels of CNS
Occur on the order of seconds to minutes

Question 43

What is biased information processing?

Answer 43

• Biased information processing: you’re seeing shifts in behavior because of emotions, emotions change based upon the needs of the animal (mouse diagram and avoidance behavior with the electrical grid and food)
Different emotions change the way an organism sees the world, perception isn’t a passive filtering of information, it affects what you see

Question 44

What does anxiety do?

Answer 44

Anxiety leads to increased threat attention and hyper-vigilance, leading to a colored perception of the world where more threat is perceived

Question 45

What’s the smoke alarm principle?

Answer 45

if you’re going to make a mistake, your brain usually makes a mistake in the direction of negative, it assumes the worst

Question 46

What is a mood?

Answer 46

○ Like an emotion, but:
§ Not necessarily tied to a specific stimulus
§ Much less differentiated
□ Positive or negative
§ Can occur over much longer time periods
§ Not as clearly associated with physiological states

Question 47

What are the characteristics of major depression?

Answer 47

§ Depressed or irritable mood
§ Decreased interest or ability to experience pleasure (anhedonia)
§ Significant weight gain or loss
§ Insomnia or hypersomnia
§ Psychomotor agitation or retardation
§ Fatigue or loss of energy
§ Feelings of worthlessness or excessive guilt
§ Diminished ability to think or concentrate
Recurrent thoughts of death or suicide

Question 48

What’s the inflammation theory of depression?

Answer 48

○ Very strong overlap with the sickness response, induced by the same cytokines within the brain (interleukin 1 beta)
○ The only way to distinguish sickness response and depression is by looking at timelines
○ If you give a mouse that’s suffering from sickness response, you can reduce sickness response by getting serotonin in the brain
○ Primary mechanism that’s modulating this is levels of serotonin
○ Patients that were suffering from cancer, some given interferon chemotherapy treatment (immune) and some were given a different kind of chemotherapy
The patients who had the immune chemotherapy had much worse off mood, more depression symptoms, elevated immune levels in the blood years later

Question 49

Why do we display emotions?

Answer 49

○ Serves an adaptive purpose: flexion reflex with pain
○ Serves to communicate to conspecifics: alarm call, crying, laughing
○ Serves to communicate to predators: pronking or stotting
○ Serves to change behavior in target: smiling
○ We often implicitly alter our behavior based upon who we’re around, whether they’re people we don’t like, or family, or close friends

Question 50

What is the difference between challenge and threat responses?

Answer 50

○ The challenge state is feeling like you have a “fighting chance”, while threat state is about feeling like you’re outmatched

Question 51

What are emotions typically associated with?

Answer 51

Emotions are typically associated with pronounced patterns of activity in the autonomic nervous system and HPA axis

Question 52

What is a genetic moderator of resilience?

Answer 52

serotonin transporter gene, which is responsible for taking serotonin out of synaptic cleft, individual polymorphisms make the transporter more or less effective

Question 53

What is stress inoculation?

Answer 53

○ Comes from the inverted U idea
○ It is the case that exposure to moderate stressors throughout your life makes you better at dealing with them
○ US Army on exercise - “progressively greater exposure to physical stressor is required”, mild to moderate stressors that are increasing over time
○ Familiar stress over time - you habituate to it
○ Also remember the placebo effect
○ Repeated stress, but the worst case scenario doesn’t actually happen, so your stress responses get less extreme and more manageable

Question 54

What is active coping?

Answer 54

gather information, acquire skills, confrontation, problem solving, seek social support, and cognitive reappraisal (challenge as opposed to a catastrophe, seeing the bigger picture)

Question 55

What is passive coping?

Answer 55

deny the problem, avoid or withdraw, substance use, negative venting, cognitive rigidity, blaming

Question 56

Controllable is blank focused, while uncontrollable is blank focused

Answer 56

Controllable is problem-focused, while uncontrollable is emotion-focused

Question 57

What are some good habits associated with resilience?

Answer 57

○ Acquire information about stressor
○ Learn skills necessary to deal with or adapt to stressor
○ Have a plan and a back-up plan
○ Practice plan and back-up plan
○ Discuss stressor with trusted colleagues when possible
○ Don’t be afraid to fail (if you fail correctly)
There are a lot of different ways to fail

Question 58

What are the psychosocial factors of resilience?

Answer 58

○ Find resilient role models
		○ Humor - making light of something
		○ Develop active coping strategies
		○ Practice regulating emotions
		○ Help others
		○ Take advantage of social support
		○ Cognitive flexibility (positive reappraisal)
		○ Physical and psychological training
		○ Allow time for physical and emotional recovery
Focus on purpose and meaning - refocus