Week 8 - topic 1 and 2 Flashcards
Fear and the brain - patient SM
- SM had damage to her amygdala.
- This resulted in her having a lack of fear.
- Fear is an example of an emotion that consists of a feeling (being afraid), physiological changes (increased heart rate), and behaviours (fighting, freezing, or fleeing)
Components of emotion
Emotional response made up of:
- behavioural components -> muscular movements that are appropriate to the situation that elicits them
- autonomic components -> quick mobilization of energy for vigorous movement
- hormonal components -> reinforce the autonomic responses
The amygdala
- Neurons in the amygdala become active when emotionally relevant stimuli are presented
- Located within the temporal lobes
Lateral, Basal and Central Nuclei (Amygdala)
Lateral nucleus (LA) • Receives information from the neocortex
Basal nucleus (B) • Receives information from LA
Central nucleus (CE)
• Receives information from the LA and B nuclei
• Projects to the hypothalamus, midbrain, pons, and medulla
• Responsible for the expression of various components of emotional responses
Central nucleus of the amygdala
- Most important part of the brain for expression of emotional responses provoked by aversive stimuli
- Neurons activated when threatening stimuli are perceived
- Animals show physiological and behavioural signs of fear and agitation
- Responsible for harmful effects of long-term stress
The central nucleus and conditioned emotional responses
- Some stimuli automatically activate the central nucleus and produce fear reactions
- Other stimuli result in a Conditioned Emotional Response (CER) = when neutral stimulus is paired with emotion-producing stimulus
- Physical change responsible for producing CER occur in the lateral nucleus and communicate with the central nucleus, which in turn project to broad areas that are responsible for autonomic, behavioural and fear components of emotion response
Amygdala and emotional memories - Mori et al (1999)
in a study conducted by Mori et al. (1999) researchers studied the memory of Alzhiemer’s disease on a group of participants memory for an emotionally charged event (devestating earthquake). Overall, the authors found that patients with greater amygdala damage were less likely to remember the traumatic event.
ventromedial Prefrontal Cortex (vmPFC)
• Inhibits or prevents fear responses
• Located at the bottom front of cerebral hemispheres
• Inputs provide information about what is happening in the environment and plans made by the frontal lobes
• Outputs affect a variety of behaviours and physiological
responses
vmPFC live snake toy bear experiment
The participants’ task was to get as close as possible to either a live snake or a toy bear, by repeatedly choosing whether to bring the object closer or move it away, while undergoing fMRI brain scanning.
A display of courage was accompanied by activation of a region of the vmPFC
Serotonin and aggression
• The activity of serotonergic synapses inhibits
aggression
• In a study of monkeys, animals with lowest serotonin
levels (5-HIAA) showed a pattern of risk-taking
behaviour, including high levels of aggression
• Exerts a controlling influence on risky behaviour -
reduced serotonin release is associated with human
aggression and other forms of antisocial behaviour
Ventromedial PFC and emotions
• Inhibits emotional behaviour, such as impulsive violence or aggression
• Damage to it causes serious and impairments of
behavioural control and decision-making
• Example: After Phineas Gage’s vmPFC was damaged
by a steel rod, he became a different person
Damage to the vmPFC
• Damage to the vmPFC effects emotional regulation
• Emotional reactions guide moral judgments and
decisions involving personal risks and rewards
• Not simply the products of rational, logical decision making processes
• Individuals with vmPFC damage make decisions without a strong emotional component and select the most practical solution
Facial expressions
- Facial expressions take approximately the same form in people from all cultures (Ekman)
• Therefore expression involves innate and unlearned responses consisting of a complex movement of muscles (especially those of the face)
• Those who are blind make the same emotional expressions as those who are not
• A vocal version of the cross cultural emotion task found that nonverbal vocalizations of emotion are similar across different cultural experiences
Communicating emotion
- Effective communication requires both producing and recognizing emotions - so the ability to display emotion is only going to be useful if someone can recognize that emotion
- People tend to display emotion more overtly when they are in the presence of others. For example, bowlers making a strike tend to only produce small signs of emotion when alone, but when with other people, are much more likely to smile.
Recognising emotion
- recognizing emotions is thought to generally be automatic, rapid an accurate.
- Research suggests that when given additional time to process emotions, judgments become no better.
- Interestingly, we can also use posture and body language to help others with recognizing our emotions.
- > For instance, showing people photos of people’s faces either with or without accompanying body postures influenced emotion recognition
