neurotransmitters Flashcards
outline the 2 NT linked to aggression
dopamine and serotonin
how does serotonin cause aggression
serotonin has a calming influence and low levels of serotonin mean that people can’t control their impulsive and aggressive behaviour. there is a weaker signalling/communication with amygdala and PFC so lack problem solving and remorse. Serotonin also regulates the pre-frontal cortex; therefore, lower levels of serotonin affect our response to external stimuli, meaning the person becomes aggressive easily and can’t control their responses in a ‘normal’ way. They can’t anticipate risk and therefore impulsively engage in aggressive behaviour.
how does dopamine cause aggression
Dopamine – has been identified as it is linked to the dopaminergic pathway, which results in pleasure, which is a rewarding feeling and a desire to repeat certain behaviours. This is why dopamine has been linked to addiction and substance abuse, and therefore through this it has an indirect link to criminal behaviour.
impulsive behavior may be enhanced by elevated dopaminergic function Stimulants increase impulsivity in humans without the presence of an ADHD disorder.
D2 receptor antagonists showed reduced ability to recognise facial expressions leading to lack of remorse.
give research to support serotonin as a cause of aggression.
healthy volunteer altered diet to change levels of serotonin. they were given a mixture of tryptophan, amino acids and building block for serotonin. on placebo day they were given the same mixture with normal amount of tryptophan. they then had an fmri scan and viewed anger, sad and neutral facial expressions.
the results showed that low levels of serotonin made communication with the amygdala and prefrontal cortex weaker then when there were normal levels of serotonin.
they also used a personality questionnaire to determine individuals with a natural tendency to be aggressive. these individuals had an even weaker communication with amygdala and PFC following serotonin depletion. these individuals were the most sensitive to changes in aggression due to serotonin depletion.
what is the application
Atypical antipsychotic agents, such as risperidone, clozapine and olanzapinehave also been found to be effective in treating impulsive aggression.
give research to support dopamine as a cause of aggression
Studies on aggressive behaviors in rodents showed that elevated dopamine levels have been continuously observed before, during, and following aggressive fights (Hadfield, 1983)
low generalisability as research is conducted on rats so cannot say that dopamine has the same effect in humans as it does in rats.
