Lecture 20: Emotion Flashcards
Emotions
Mental reaction typically accompanied by physiological and behavioral changes in the body
6 Primary Emotions
Anger, disgust, fear, happiness, sadness, and surprise
Feelings
Conscious awareness and reactions to emotions
Worry, homesick, content, bitter, jealous
The Expressions of Emotions in Man and Animals
- 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
James-Lange Theory of Emotion
- Proposed that physiological reaction in the body due to stimulus causes the emotion
- Bottom-up theory (body to the brain)
Cannon-Bard Theory of Emotion
-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
Two-Factor Theories (Schacter and Singer’s Experiment)
-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
Hypothalamus
- Highly conserved structure
- Contains nuclei that influence reproductive, appetitive, and agnostic behaviors
- Fundamental to animals and humans
- Receptors monitor the composition of the blood
Autonomic Output Pathway
Pathway going from the hypothalamus to the sympathetic and parasympathetic nervous systems
Motivational Pathway
Pathway going from the hypothalamus to the forebrain, causing it generate complex plans (go drink water, stop eating, etc.)
Neuroendocrine Pathway
Pathway going from the hypothalamus to the pituitary gland to regulate hormones
HPA Axis
- 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
Evidence that the hypothalamus is involved in emotional regulation
- 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
Optogenetics
- 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
Deep Brain Stimulation (DBS)
A method to electrically stimulate brain structure in human patients
