1. neural factors Flashcards
the limbic system
area of the brain to co-ordinate behaviour that satisfy motivational and emotional urges eg agression & fear
key structures: amygdala,hippocampus
neural mechanisms in agression
the limbic system and serotonin
the limbic system
THE AMYGDALA
responsible for quickly evaluating the emotional importance of sensory information and responding
areas electrically stimulated animals snarl= agression
removed= reduced violenence
narabayashi et al= 43/51 patients with operations to remove had more normal social behaviour after, reduced agression
the limbic system
THE AMYGDALA
EVALUATION
supporting evidence
pardini et al
pardini et al
reduced volume predicts development of severe persistent agression
longitudinal study
male childhood-adulthood
56 pp MRI at 26
lower volume=more agression
role evaluating emotional importance of sensory information
the limbic system
THE AMYGDALA
EVALUATION
exact role is unclear
contradicitory research
muller et al
6 male psychopaths
series of positive or negative images
brain activity foud increased activity
the limbic system
the hippocampus
formation of long term memories
animals compare conndition of current threat with similar experiences= appropriate response
imparied= nervous system can’t put into relevant meaningful context so responds inapropriately
the limbic system
the hippocampus
EVALUATION
supportive researcjh
Raine et al
2 groups of violent criminals
1 impulsive vs ‘cold calculating criminals’
impulsive hasd different sized hippocampus
asymetry impacted ability of amygdala and hippocampus to work together
emtion information not processed properly= inapropriate verbal physical responses
the limbic system
EVALUATION
supportive research
Summer et al 2007
case study
14 yr old girl
fMRI scan
tumour in limbic system
had epileptic seizures and very agressive
treated with drugs= agression became normal
high agression links to limbic system
serotonin
neurotransmitter
impulses between neurons
normal levels=calming inhibitory effect on firing neurons in brain
low levels stop inhibitory effect
less able to control impulses and agressive responses
major waste of serotonin low in cerebrospinal fluid of agressive people
serotonin
supportive research Mann et al
35 pp given dexfenfluramine known to use up serotonin
questionnaire asses hostility and agressive levels= dexfenfluramine treatment in malesassocisated with hostility and agression scores
