Lecture 20: Emotion

Question 1

Emotions

Answer 1

Mental reaction typically accompanied by physiological and behavioral changes in the body

Question 2

6 Primary Emotions

Answer 2

Anger, disgust, fear, happiness, sadness, and surprise

Question 3

Feelings

Answer 3

Conscious awareness and reactions to emotions

Worry, homesick, content, bitter, jealous

Question 4

The Expressions of Emotions in Man and Animals

Answer 4

• Book written by Darwin
• Emotional expressions as involuntary indicators of internal state
• Argued that animals’ emotional expressions are homologues of human emotions
• And that common facial expressions appear in humans of all ages, genders, and cultures

Question 5

James-Lange Theory of Emotion

Answer 5

• Proposed that physiological reaction in the body due to stimulus causes the emotion
• Bottom-up theory (body to the brain)

Question 6

Cannon-Bard Theory of Emotion

Answer 6

-Challenged James-Lange
- Cats with disconnected visceral innervations still hissed and growled at a dog
- Similar changes occur in different emotions, so how does your brain know which emotion to feel under bottom-up processing
- Bodily responses are too slow to generate the emotion
- Conducted experiments demonstrating the role of the thalamus and hypothalamus in emotional behavior
- Suggested a more top-down model than James-Lange

Question 7

Two-Factor Theories (Schacter and Singer’s Experiment)

Answer 7

-Subjects were injected with saline (salt water) or epinephrine (adrenaline)
– Of those injected with epinephrine, half were told that they were injected with adrenaline and half were not told about it
- Subjects interacted with two actors, one was an angry actor and one was a euphoric actor
- People injected with saline shows mild emotional responses to both actors
- Uninformed epinephrine injectees showed strong responses to both actors (angry or happy respectively)
- Informed epinephrine injectees showed mild responses to the two actors
- Shows that awareness inhibited the emotions that adrenaline caused
- Shows top-down and bottom-up in action

Question 8

Hypothalamus

Answer 8

• Highly conserved structure
• Contains nuclei that influence reproductive, appetitive, and agnostic behaviors
• Fundamental to animals and humans
• Receptors monitor the composition of the blood

Question 9

Autonomic Output Pathway

Answer 9

Pathway going from the hypothalamus to the sympathetic and parasympathetic nervous systems

Question 10

Motivational Pathway

Answer 10

Pathway going from the hypothalamus to the forebrain, causing it generate complex plans (go drink water, stop eating, etc.)

Question 11

Neuroendocrine Pathway

Answer 11

Pathway going from the hypothalamus to the pituitary gland to regulate hormones

Question 12

HPA Axis

Answer 12

• Hypothalamic-pituitary-adrenal axis
• Key mediator of response to stress
  1. Hypothalamus releases corticotropin releasing factor (CRF; master stress trigger)
  2. Gets detected by the pituitary gland and starts the bodies response to stress
  3. Pituitary gland secretes adrenocorticotropic hormone (ACTH)
  4. Adrenal glands (kidneys) secretes glucocorticoid hormones (cortisol in humans and corticosterone in rats)
  5. Cortisol triggers fight or flight reactions
  6. Negative feedback on the hypothalamus and pituitary to stop the cycle

Question 13

Evidence that the hypothalamus is involved in emotional regulation

Answer 13

• Place a small rat with a larger, dominant rat
  - Decreased defensive behavior in the small rat when the hypothalamus has been lesioned
• Electrical stimulation of medial hypothalamus in cats induces defensive rage behavior
• Presented light to light-sensitive neurons in the hypothalamus
• Behavior changes with light vs. no light
• Deep brain stimulation

Question 14

Optogenetics

Answer 14

• A method for inducing or suppressing neural activity (action potentials) with light
• Light-sensitive ion channels introduced into neurons and now they express those channels into membranes
• Shining light causes neurons to spike
• Optic fibre cable w/ light is implemented into the brain allowing us to fire neurons when we want

Question 15

Deep Brain Stimulation (DBS)

Answer 15

A method to electrically stimulate brain structure in human patients

Question 16

Amygdala

Answer 16

• Widely associated with fear and emotion
• receives rich sensory information
• Sends info to hypothalamus, brain stem, and cortex

Question 17

Basolateral Amygdala (BLA)

Answer 17

Input of the amygdala

Question 18

Central Amygdala (CeA)

Answer 18

Output of amygdala

Question 19

Evidence that amygdala is involved in fear

Answer 19

• In the 1930s Kluver and Bucy removed temporal lobes of monkeys (including the amygdala)
• Displayed hyperorality, hyper sexuality, lack of fear
• Deficiency in predicting negative outcome
• In the 1950s Weiskrantz tested role of amygdala in fear learning
• Monkeys underwent avoidance conditioning
• Control monkeys learned rapidly
• Monkeys w/ amygdala lesions did not