physiological psychology attack and escape behaviours lecture 25 mar 17 2014
DESCRIPTION
A powerpoint presentation aid to accompany a 1 hour lecture on various topics in Physiological Psychology (a second year Canadian University course): Attack and escape behaviours; serotonin, androgens and violence; amygdala and fear.Slide 1: Attack and Escape behaviours engage the corticomedial area of the amygdalaSlide 2: Correlation between cigarettes smoked by pregnant mothers and the amount of violent crime the prenatal child would commit later in their lives. Perhaps if a pregnant women smokes cigarettes, the baby in her womb will be more violent?Slide 3: Violence and MAO(A) levelsSlide 4: Testosterone levels in offendersSlide 5: Prenatal testosterone (measured in the mother) contributes to aggression (in the unborn child)Slide 6: Androgens influence frequency of biting attacks in MiceSlide 7: Testosterone injection increases participant's ability to identify angry expressionsSlide 8: Homicide rates in selected cities (London England; Paris France; Athens Greece; Moscow Russia; Berne Switzerland; Canberra Australia; Ottawa Canada; Tokyo Japan; Pretoria South Africa; New York USA; Washington, D.C USA)Slide 9: Connection between aggressive behaviour and low Serotonin turnoverSlide 10: Serotonin turnover is inferred by measuring levels of 5-hydroxyindoleacetic acid (5-HIAA, a serotonin metabolite) in either blood, cerebrospinal fluid or urine samples. Slide 11: Links between serotonin turnover and violent crimeSlide 12: Serotonin activity can be influence by genetics since genes control the production of the enzyme that makes serotonin (the enzyme is called tryptophan hydrozylase- an enzyme that makes serotonin from the amino acid tryptophan)Slide 13: Amygdala brain areas and FearSlide 14: A study shows that the amygdala of the viewer becomes more active when processing the target's negative emotion if the target's eyes are looking either at or away from the viewer. If the target is displaying anger, the viewer's amygdala is more activated when the target's eyes are looking away from the viewer, rather than at the viewer. Perhaps if you are angry, you should direct your eyes away from your friends because their emotion-processing areas of the brain will be more active and responsive to you. In addition, if the target is displaying fear, the viewer's amygdala will be more active if the gaze is directed at the viewer. Perhaps if you are afraid, looking at the person you are interacting with will get their attention more than looking away.Slide 15: drawings of an individual who is not capable of feeling fear due to brain damage. Drawings of all other emotions are accurate, but because the patient does not even know how to begin visualizing what a fearful face looks like, the patient instead draws a baby.Slide 16: Amygdala and the eyes - due to social contagion, just seeing fear activates the amygdala. The greater the amount of eye-whites are available, the more we perceive fear.Slide 17: Major facial expressions of emotions are easily recognized around the world, crossing boundaries of race, culture, socialization and nation. To display and recognize emotions is to be human.Slide 18: Facial expression pathologies: Volitional facial paresis (difficulty in voluntary facial movements) & Emotional facial paresis (difficulty in natural facial movements)This powerpoint presentation was prepared by Dr. Smilek using figures and tables with permission from Biological Psychology. I take no credit for anything.TRANSCRIPT
Attack and Escape Behaviors
• Attack behaviors are associated with increased activity in the corticomedial area of the amygdala.
• An initial attack behavior increases the probability of a second attack behavior.
Violence
• Violence is particularly enhanced with both a genetic predisposition and an early troubled environment.– Example: Interaction
between MAOA levels and childhood maltreatment
Research shows that men with the highest rates of violent behavior also have slightly higher testosterone levels.
Testosterone
Prenatal Testosterone Contributes to Aggression
Androgens Influence Biting Attacks in Mice
Injecting women with testosterone decreases their ability to identify angry expressions.
Testosterone
Homicide Rates in Selected Cities (1998-2000)
Serotonin
• Studies also suggest a connection between aggressive behavior and low serotonin turnover.• Turnover is the amount of a neurotransmitter
that is released and resynthesized by neurons.• E.g., social isolation of male juvenile mice
decreased serotonin turnover and increased aggressive behavior.
Serotonin
• 5-hydroxyindoleacetic acid (5-HIAA) is a serotonin metabolite found in the blood, cerebrospinal fluid, and urine that allows researchers to infer turnover rate.– High levels of 5-HIAA imply much serotonin
release and turnover.– Research with monkeys has demonstrated that
low levels of 5-HIAA increases the probability of attack on larger monkey• few survived past age 6.
Serotonin
• In human studies, low serotonin turnover has been linked to: – People with a history of
violent behavior and violent crime.
– People who attempt suicide by violent means.
– Recurrent violent behaviors.
Serotonin
• Serotonin activity can also be influenced by genetics.
• Genes control the production of tryptophan hydroxylase.
• People with less active form of this enzyme are more likely than others to report frequent anger and aggression.
Amygdala and Fear
Amygdala & Fear
Amygdala & the eyes
Major Facial Expressions of Emotions Are Easily Recognized Around the World
Facial Expression• Volitional facial paresis– difficulty in voluntary facial
movement, natural movement is fine
– damage to motor cortex and subcortical connections
• Emotional facial paresis– voluntary movement is fine;
natural movement impaired– damage to PFC, thalamus,
white matter of the frontal lobe