Option 3: Aggression Flashcards
what are the neural mechanisms in aggression?
the limbic system
serotonin levels
what is the limbic system?
the limbic system is compromised of the cingulate gyrus, hypothalamus, fornix and amygdala.
what is the most important structure of the limbic system?
the amygdala.
what is the role of the amygdala and how is it linked into aggression?
this has a key role in humans and non-human animals in how an organism assesses and responds to environmental threats and challenges.
the reactivity of the amygdala in humans has proven to be an important predictor of aggressive behaviour.
explain the procedure of the Gospic et al. study which shows the link between the amygdala and aggression.
procedure: Gospic et al. (2011) used a well-established laboratory method of assessing aggressive behaviour called the ultimatum game. this features 2 players. the proposer offers to split money in a certain way with the responder. if the responder accepts, the money is split as proposed. but if the responder rejects the offer, both receive nothing. ppts in the study played as responders while having their brains scanned by fMRI, which highlights activity in different areas of the brain.
explain the findings of the Gospic et al. study which shows the link between the amygdala and aggression.
findings: the researchers found that when responders rejected unfair offers, scans revealed a fast and heightened response by the amygdala. they also found that a Benzodiazepine drug (which reduces arousal of the autonomic nervous system) taken before the game had 2 effects on responses to unfair offers; it halved the number of rejections (reduced aggression) and decreased the activity of the amygdala.
explain the conclusion of the Gospic et al. study which shows the link between the amygdala and aggression.
this is strong evidence of an association between reactive aggression and amygdala activity.
what is serotonin?
serotonin is a neurotransmitter involved in communication of impulses between neurons. it has widespread inhibitory effects on the brain; it slows down and dampens neuronal activity.
what do low levels of serotonin result in?
normal levels of serotonin in the orbitofrontal cortex are inhibitory and linked with reduced firing of neurons and associated with greater behavioural self-control.
decreased levels of serotonin disturbs this mechanism, reduces self-control and increases impulsive behaviours, including aggression
how does the study of Virkkunen et al. further support the link between serotonin and aggression?
Virkkunen compared levels of serotonin break-down product in the cerebrospinal fluid of violent impulse and violent non-impulse offenders. the levels were significantly lower in the impulsive offenders, and they also suffered from more sleep irregularities. this is significant because serotonin regulates sleep patterns. the disturbance of this pattern strongly implies some disruption of serotonin functioning further supporting the role of serotonin in reactive aggression.
