Chapter 7: Pain, Fear, Comfort

Question 1

Thermoregulation

Answer 1

Motivation to seek comfort in reaction to excess heat or cold

Question 2

Heat Conversation –> Posterior Nucleus of Hypothalamus –> Anterior Pituitary

Answer 2

Increased thyroid hormone secretion (thyroid responsible for metabolism–increases metabolism, breakdown molecules build energy)
Increased sympathetic NS activation
Shivering, piloerection (goosebumps), vasoconstriction (reduce blood flow to extremities)

Question 3

Heat Dissipation –> Preoptic Nucleus of Hypothalamus –> Anterior Pituitary

Answer 3

Decreased thyroid hormone secretion (decrease metabolism)
Decreased sympathetic NS activation (more blood to extremities)
Sweating, panting, thirst, vasodilation

Question 4

Where does pain originate?

Answer 4

Nociceptors/free nerve endings

Mechanical & thermal stimuli

Question 5

Fibers involved in pain sensation

Answer 5

C: Unmyelinated –Slow, dull, aching pain

Aδ: Myelinated –Sharp, fast, pricking pain

Question 6

Where to the fibres involved in pain perception synapse?

Answer 6

Pain fibers synapse at the dorsal horn of spinal cord

Question 7

3 pathways to the pain

pain perception

Answer 7

1) Spinothalamic–>Thalamus
- Medial and lateral thalamus
- Cortex

2) Spinoreticular –> Reticular System
- Medial thalamus
- Cortex

3) Spinomesencephalic –> Midbrain
- Reticular formation & PAG
- PAG signals to hypothalamus

Question 8

Endorphins & Enkephalins related to Analgesia

Answer 8

Endorphins: Released from pituitary during stress
CRH (hypothalamus) –>ACTH +B-endorphin (anterior pituitary)

Enkephalins: Small peptides
concentrated in PAG and dorsal horn of spinal cord

Endorphin Receptors:
Concentrated in (PAG) and dorsal horn of spinal cord

Endorphins, enkephalins, and opioids (morphine, oxycodone, heroin) interact
with these receptors to produce analgesia

Question 9

Visual Analog Scale (VAS)

Answer 9

used in medical assessments of pain perception (perception and tolerance varies amongst individuals)

Question 10

Adaptations Level Hypothesis

Answer 10

subjective intensity of pain relative to previous experiences

Question 11

Pain vs Fear

Answer 11

Pain: response to actual damage
Fear: response to the anticipation of damage that might occur

• Ancestral dangers are most salient (heights, predators, snakes, spiders, darkness)
• Novel, but real, dangers are less salient

Question 12

Responses to Fear

Answer 12

Hard to become unfearful of things
Fear remains due to unlikely exposure to fearful stimuli

Higher response to fear in females, younger
Innate responses may interfere with learning new fear responses

Question 13

Innate Responses to Fear

Answer 13

Species-Specific Defense Reactions:
Fleeing, freezing, fighting

Other Reactions:
Hiding
Burying, burrowing
Perspiration
Urination, defecation
Vocalizations, crying, screaming

Question 14

Fear Physiology

Answer 14

Sympathetic NS reflexes

Adrenal catecholamines (adrenaline and noradrenaline)
- involved in sympathetic responses

Central catecholamines (dopamine and noradrenaline)
- levels elevated following exposure to aversive stimuli

Question 15

Dorsal Hypothalamus

Answer 15

Stimulation produces flight behaviour, rapid breathing, pupil dilation, urination, defecation in a number of species

Question 16

Periaqueductal Grey (PAG)

Answer 16

Stimulation turns calm and placid animals into ones that are highly defensive and scared

Question 17

Sympathetic NS Reflexes (fear physiology)

Answer 17

Pupil dilation
Increase in Perspiration
Increased Liberation of energy 
Acceleration of defense reactions
Elevated heart rate & respiratory rate
Increased heart and lung function

Elevated blood pressure
Constriction of blood vessels–supplying skin, digestive tract, brain, smooth muscle (alpha-1 receptor, NE)
Dilation of blood vessels in muscle –supplying skeletal muscles
(beta-2 receptor, epinephrine)

Increase in adrenal medulla function 
Inhibited digestion (gastrointestinal reflexes)
Decreased stomach and intestinal function
Inhibition of lacrimal and salivary glands 
Inhibited sexual responses

Question 18

Extreme or Intense Arousal

Answer 18

Loss of peripheral vision
Piloerection (“goose bumps”)
Shaking
Spontaneous urination and defecation

Question 19

Amygdala & Fear

Answer 19

Critical for balance of approach & avoid, anger & fear
Electrical stimulation of lateral areas can induce fear, defensive behaviours, alertness
Electrical stimulation of other areas can diminish fear and defensive behaviours

Question 20

Basolateral nucleus

amygdala nuclei

Answer 20

Integration of sensory stimuli and memories during fear conditioning

Question 21

Cortical nucleus

amygdala nuclei

Answer 21

Involved in sense of smell and pheromone-processing

Receives input from olfactory bulb and olfactory cortex

Question 22

Centromedial nucleus

amygdala nuclei

Answer 22

Involved in emotional arousal

Question 23

Hypothalamus

Answer 23

activation of sympathetic NS

Question 24

Thalamic Reticular Nucleus

Answer 24

increased reflexes

Question 25

Trigeminal and Facial Nuclei

Answer 25

integration of emotion and face processing

Question 26

Ventral Tegmental Area
Locus Coeruleus
Laterodorsal Tegmental Nucleus

Answer 26

activation of dopamine, norepinephrine, epinephrine

Question 27

Urbach-Wiethe Disease

Answer 27

Gradual atrophy of amygdala

No special memory for traumatic events
Difficulty recognizing fear in others
Reduced fearfulness
Shrinking and death of amygdala tissue

Question 28

Anxiety

Answer 28

GABAA receptor binds benzodiazepines (valium)
GABA blocking drugs can induce panic (blocking GABA induces anxiety)
CCK4 injection into amygdala can induce panic