Chapter 11: Emotions, Aggression, and Stress Flashcards
Compare and contrast James-Lange, Cannon-Bard and Schacter’s theory of emotions.
James-Lange theory: proposed that autonomic reactions trigger feelings (stimulus - perception of danger - specific autonomic pattern - fear)
- no successful attempts at linking specific emotions to specific bodily response.
- physiological reactions are also rather slow
Cannon-Bard theory: proposed that there is a simultaneous feeling and autonomic reaction.
- cognitive processes: cerebral cortex decides which particular emotion is an appropriate response.
Schacter’s theory
- we use emotional labels to describe the feelings of physiological arousal
- the emotion we “feel” depends on cognitive systems that assess the context (i.e., our current social, physical, and psychological situation)
important takeaway: Schacter and Singer experiment showed that autonomic responses can intensify our emotions, but our cognitive analysis affects which emotion we experience.
Discuss Plutchik’s theory and view on facial expression
He proposed that a basic core set of emotions may underlie all feelings
He suggests eight basic emotions, in four pairs of opposites: joy/sadness affection/disgust anger/fear expectation/surprise
They differ in level of intensity.
Keltner and Elkman’s theory of facial expressions
Keltner and Elkman included embarassment and contempt instead of affection and expectation.
Discuss the cultural differences of facial expressions.
- cross-cultural similarity is noted in the production of the expression of specific emotions, yet some isolated groups do not recognize expressions of surprise and disgust.
- subtle cultural differences suggest that cultural conditioning enforces prescribed rules for facial expression
Describe the muscles in the face and which neural pathways innervate them.
Facial expressions are mediated my muscles, cranial nerves, and CNS pathways
Two categories of facial muscles
- superficial facial muscles - attach between points of facial skin
- Deep facial muscles - attach to skeletal structures in the head.
Facial muscles are innervated by two cranial nerves: the facial nerve (VII) and the trigeminal nerve (V)
Discuss how brain lesions affect emotions (decorticate rage, Kluver-Bucy syndrome)
Decorticate rage - or sham rage, a sudden intense rage in dogs with their cortex removed - suggests that the cortex inhibits rage.
James Papez suggested that the destruction of the interconnected brain regions within the limbic system would impair emotional processes.
Kluver-Bucy syndrome: characterized by emotional changes, such as reduction of fear and anxiety, after bilateral amygdala damage.
Discuss the low-road and high-road of the amygdala.
Studies show that the amygdala is a key structure in the mediation of fear. It is located in the temporal lobe
Low-road
- fear-provoking stimuli reach the thalamus and are directed to the amygdala
- bypasses conscious processing for immediate reaction
- doesn’t go to cortex.
- exists so that you don’t die.
High-road
- stimuli is routed through the thalamus to sensory cortex, then to the hippocampus
- allows for slower, more controlled processing
- allows you to evaluate the situation and then make a decision.
Explain the brain regions affected by feelings of love
Love seems to affect the executive control area (PFC). Activity is decreased when the person is looking at the person they love.
Decreased amygdala response when looking at partner.
Increased activity in insula when consciouss\ly aware of his/her feelings.
What is aggression and what are the biological mechanisms underlying it?
Aggression is a behavior intended to cause pain or harm to others.
Testosterone increases aggression in many species, but the relationship in humans is less clear.
Two variables confound this relationship:
- Observation that experience can affect testosterone levels.
example: in men, testosterone levels rise in the winners and falls in the losers. - Dominance
- proactive aggression: meant to improve an individual’s standing in comparison to others in order to achieve a social outcome.
Describe the role of neurotransmitters and aggression.
Serotonin likely inhibits aggression.
Other neurotransmitters have also been linked to aggression, such as GABA, dopamine, and peptide hormones (vasopressin)
The brain circuit that mediates aggression appears to go from the medial amygdala to the ventromedial hypothalamus (VMH).
The medial amygdala analyzes olfactory info (such as allowing male rats to distinguish between male rivals to be attacked and females to be courted)
The ventromedial hypothalamus then decides to either trigger an aggressive response or not.
Describe the first stage of stress response.
Alarm Reaction
- hypothalamus activates the sympathetic nervous system - “fight or flight”
- adrenal medulla releases epinephrine (adrenaline) and norepinephrine (noradrenaline)
- adrenal cortex releases adrenal steroid hormone such as cortisol to ready the body for action.
What is the role of the anterior pituitary in stress?
The anterior pituitary releases hormones that lead to the release of cortisol, epinephrine and norepinephrine. As stress level decreases, so do hormone levels.
Second stage of stress response
Adaptation - body goes back to normal after a single stressor; glucose, adrenaline and cortisol stay high
Third stage of stress response
Exhaustion - reaction to prolonged or frequently repeated stress - leads to increased risk of disease
Discuss stress immunization
- mild stress early in life = easier to handle stress later in life
- in rats, the early stress was beneficial only if mothers comforted the pup afterward
- pups who received little maternal attention showed a greater stress response as adults and changes to the expression of adrenal steroid receptors in the brain.
This is epigenetic regulation, which is a change in gene expression, not in genes themselves, due to environmental factors
