Neural and Hormonal mechanisms in aggression Flashcards
(18 cards)
where in the brain is aggression located
limbic system
what is the limbic system
helps to coordinate behaviours that satisfy motivational and emotional urges such as aggression and fear
2 key structures of the limbic system
amygdala + hippocampus
what is the amygdala
where quick evaluation of sensory info happens and it prompts an appropriate response
stimulation of the amygdala = an aggressive response , eg snarling
if it is removed the animal no longer responds to things that would normally produce rage
what is the hippocampus involved in forming
LTMs
what does the hippocampus do
allows animal to compare a current threat to a past experience
impairment to the hippocampus prevents the nervous system from…
may cause the amygdala to respond inappropriately to sensory stimuli = aggressive behaviour
what does the effect of a normal level of serotonin exert on neuronal firing in brain
calming and inhibitory effect
consequence of low levels of serotonin on the amygdala
less inhibition, makes aggression more likely
how is testosterone linked to aggression
produces male characteristics, including aggression
what happens when testosterone levels are manipulated in animals
reduces aggression + increasing it leads to aggressive behaviour returning
who has higher t levels
men = more aggressive behaviour
Dabs et al 1987
those with higher levels of T committed violent crimes
lower levels of T committed only non-violent crimes
AO3 support for role of amygdala in aggression
Pardini et al 2014
conducted a longitudinal study from childhood to adulthood on 56 males with varied histories of aggression
MRI scan used to measure volume of amygdala
relationship found between amygdala volume and levels of aggression and violence
suggests that amygdala plays a key role in evaluating sensory info + lower volume makes aggression more likely
AO3 support for role of hippocampus in aggression
Raine et al 2004
found differences in the left and right hemispheres on convicted violent criminals but not in unconvicted vio criminals
Hippocampus in the right and left hemispheres were different in size in the convicted vio criminals brains
This may impair the ability of the hippocampi and the amygdalae to work together = leads to incorrect processing of emotions and inappropriate responses.
support for the role of serotonin in aggression
Rosado et al
used dogs of varied breeds referred to spanish vets for aggy behaviour towards humans
80 dogs = control group 19- aggy group
control grp = 278 units of serotonin
aggy grp = 387 units of serotonin
mixed evidence in humans - some studies finding a diff in levels of aggressive vs non-aggressive, and other studies not finding a difference
-some research has found that when men take drugs which increase serotonin levels, aggy decreases/ drops
support for the role of testosterone in aggression
dab et al study
higher levels of T - committed violent crimes
lower levels of T - only committed non-violent crimes
