The Structure of the Brain and Aggression
Role of the Limbic System:
The limbic system is deep inside the brain and
was first linked to aggression by James Papez
1937.
He identified the limbic system compromising
a number of structures.
Amygdala - central role in how organisms
assess and respond to environmental threats
and challenges.
IED - intermittent explosive disorder - extreme
outbursts of aggressive behaviour.
IED participants showed high levels of
amygdala activity when viewing images of
Role of the Prefrontal Cortex:
OFC - orbitofrontal cortex - region of the angry faces (had an fMRI).
prefrontal cortex just above the eye sockets. Amygdala reactivity and aggression is
Plays a role in higher cognitive functions like especially meaningful because an angry facial
rational thinking and decision making, self expression is an ecologically valid sign of
control and impulses. threat.
In patients with psychiatric disorders, the
feature of aggression and the OFC is reduced,
which disrupts its impulse control function.
Adrian Raine el at 1997 used PET scans to
Roles of Serotonin:
study murderers whose crimes included
It slows down and dampens neuronal activity.
aggression.
Normal levels of serotonin in the OFC are
They found greater glucose metabolism in the
associated with a reasonable degree of
amygdala, but abnormally low glucose in the
behavioural self-control.
prefrontal cortex.
Decreased serotonin will disturb this link,
reducing self control and leading to more
impulsive behaviours like aggression.
Role of Dopamine: Serotonin helps to regulate sleep patterns,
Involved in regulating motivated behaviour disruption of sleep implies disruption of
and our experience of reward. serotonin functioning.
Dopamine’s main influence with aggression Virkkunen et al 1994 compared levels of a
comes through the interaction with serotonin. serotonin breakdown product in the
Serotonin underactivity stimulates dopamine cerebrospinal fluid of violent impulsive and
overactivity and both are linked with violent non-impulsive offenders who suffered
impulsivity and aggression. irregular sleep patterns.
Role of the Limbic System:
The limbic system is deep inside the brain and
was first linked to aggression by James Papez
1937.
He identified the limbic system compromising
a number of structures.
Amygdala - central role in how organisms
assess and respond to environmental threats
and challenges.
IED - intermittent explosive disorder - extreme
outbursts of aggressive behaviour.
IED participants showed high levels of
amygdala activity when viewing images of
Role of the Prefrontal Cortex:
OFC - orbitofrontal cortex - region of the angry faces (had an fMRI).
prefrontal cortex just above the eye sockets. Amygdala reactivity and aggression is
Plays a role in higher cognitive functions like especially meaningful because an angry facial
rational thinking and decision making, self expression is an ecologically valid sign of
control and impulses. threat.
In patients with psychiatric disorders, the
feature of aggression and the OFC is reduced,
which disrupts its impulse control function.
Adrian Raine el at 1997 used PET scans to
Roles of Serotonin:
study murderers whose crimes included
It slows down and dampens neuronal activity.
aggression.
Normal levels of serotonin in the OFC are
They found greater glucose metabolism in the
associated with a reasonable degree of
amygdala, but abnormally low glucose in the
behavioural self-control.
prefrontal cortex.
Decreased serotonin will disturb this link,
reducing self control and leading to more
impulsive behaviours like aggression.
Role of Dopamine: Serotonin helps to regulate sleep patterns,
Involved in regulating motivated behaviour disruption of sleep implies disruption of
and our experience of reward. serotonin functioning.
Dopamine’s main influence with aggression Virkkunen et al 1994 compared levels of a
comes through the interaction with serotonin. serotonin breakdown product in the
Serotonin underactivity stimulates dopamine cerebrospinal fluid of violent impulsive and
overactivity and both are linked with violent non-impulsive offenders who suffered
impulsivity and aggression. irregular sleep patterns.
