physiology of emotions Flashcards
emotions
Feelings
Behavioural response
Cognitions
Behavioural response patterns
Three components:
Motor– muscle movements appropriate to the situation that elicits them
Autonomic – facilitate the behaviours and allows for quick mobilization of energy for vigorous movement
The Autonomic Nervous System
-Sympathetic division
Associated with energy expenditure
Derives from thoracic and lumbar levels of the spinal cord
-Parasympathetic division
Associated with energy conservation
Derives from cranial and sacral levels of the spinal cord
Behavioural response patterns
Motor– muscle movements appropriate to the situation that elicits them
Autonomic – facilitate the behaviours and allows for quick mobilization of energy for vigorous movement
Hormonal – reinforce the autonomic responses
Adrenal medulla secretes E and NE which increase blood flow to muscle and cause nutrients stored in the body to be utilised
Role of the amygdala
The 3 components of an emotional response (provoked by aversive stimuli) are controlled by separate neural systems, but all three are integrated by the amygdala.
Amygdala is part of the limbic system
The limbic system is considered phylogenetically old cortex and is primarily involved in motivation and emotion
Central nucleus of the amygdala
- Threat stimuli increase neural firing within central nucleus of the amygdala
- Lesions of central nucleus diminish emotional responses:
- Reduced fear responses to threat stimuli
- Reduced chance of developing ulcers to stress
- Reduced levels of stress hormones
- Electrical stimulation of central nucleus induces fear and agitation
Innate and learned emotional responses
- Certain stimuli naturally elicit fear reactions
- Central nucleus of the amygdala is particularly important for aversive emotional learning
- If neutral stimuli are paired with the feared stimulus, animals can learn to be afraid
Conditioning of emotional responses
- Fear stimuli elicit emotional responses
e. g. Loud noises, painful stimuli - Fear stimuli can be associated with neutral stimuli
- Tone that occurs prior to a foot shock
- Eventually, the neutral stimulus will elicit an emotional response
- Tone previously paired with shock elicits fear
- Termed the Conditioned Emotional Response (CER)
Aggressive behaviour
-Inputs from the amygdala and hypothalamus integrated by the Periaqueductal Grey Matter (PAG)
Dorsal PAG – defensive rage
Ventral PAG – predation
Role of the neocortex
-The vmPFC is especially important for humans to analyse and react emotionally to complex situations involving other people, (involving societal rules, personal experiences, memories and judgments).
vmPFC is not directly involved in making judgments but is involved in translating these judgments into appropriate feelings and behaviours
Ventromedial prefrontal cortex
- Inputs: thalamus, temporal cortex, ventral tegmental area, olfactory system and amygdala.
- Outputs to various parts of the brain including amygdala, thus affecting variety of behaviours and responses.
- Damage reduces inhibitions and self-concern; become indifferent to consequences of actions; pain no longer produces emotional response
Damaging the prefrontal cortex
Case of Phineas Gage.
Foreman of a railway construction gang
While tamping down blasting powder for a dynamite charge, Gage inadvertently sparked an explosion
The tamping iron (3 feet long, 13 pounds and 1.25 inches thick) entered his left cheek bone, obliterating his left eye on its way through his brain and out the top of his scull
Damaging the prefrontal cortex
Immediately after, Gage stood up and spoke
Within 2 months he had completely recovered
Could walk & speak
Demonstrated normal awareness of surroundings
His personality, however, changed considerably
Before accident: well balanced, shrewd, capable, and efficient
After accident: fitful, irreverent, unable to settle on any one plan
Removing the prefrontal cortex
Jacobsen, Wolf and Jackson (1935) removed the entire frontal lobes of a chimpanzee with emotional disturbances
Brickner (1936) performed a similar procedure in a human with a frontal lobe tumour; this did not result in intellectual impairment.
Psychosurgery
Egas Moniz—Tentatives opératoires dans le traitement de certaines psychoses, 1936
Nobel Prize, 1949
- Prefrontal Lobotomy
10,000 operations pre-1949 in U.S.
outcome of prefontal lobptomies
Tooth & Newton (1961) 10,365 prefrontal lobotomies 70% “improvement” 6% mortality 1% epilepsy 1.5% marked disinhibition
Lobotomy outcomes
- Patients were not only no longer distressed by their mental conflicts but also seem to have little capacity for any emotional experiences - pleasurable or otherwise.
- Resulted in personality changes including childishness, dull, apathetic, listless, without drive or initiative, flat, lethargic, placid and unconcerned, docile, needing pushing, passive, lacking in spontaneity, without aim or purpose, preoccupied and dependent.
Communication of emotions
Expression
postures, facial expression, sounds
Recognition
Visual and audial
Facial expressions signal emotion
Darwin: emotions involve innate patterns of muscle contraction, often of the facial muscles
Facial expressions signal our emotional states to others
Facial expressions are common across cultures
Facial expressions are similar in blind and sighted children
Universality of facial expression
Ekman & Friesen (1971) studied the ability of members of an isolated tribe of New Guinea to recognize facial expressions of emotion.
They had no trouble doing so and themselves produced facial expressions that Westerners readily recognized.
Culture and the expression of emotion
Display rules: rules that prescribe under what situations we should or should not display signs of particular emotions
Ekman (1972) showed a distressing film to Japanese and American college students, singly and in the presence of a visitor
When alone Japanese and American students showed the same facial expressions
When they were with another person, however, the Japanese students were less likely to show negative emotions and masked these with polite smiles
Expression of emotion
Not all muscles of the face responsible for emotional expressions are under voluntary control
volitional facial paresis
emotional facial paresis
Expression of emotion
Right hemisphere more important for emotional expression
chimerical faces
Recognition of emotion
Effective communication is a two-way process; other people must be able to recognise your emotions
Depends on vision and audition
Hemispheric specialisation: right hemisphere specialised for emotion, left for meaning
Evidence from imaging studies
Brain damage to right hemisphere impairs recognition of emotions
