neural explanation

• neural explanations refer to the brain. this can include neurochemical explanations and abnormal brain structure/ function
• abnormal neurotransmitter levels have been suggested to play a role in offending behaviour
• Brunner's research implicated an abnormality in the MAOA gene which leads to abnormally low monoamine oxidase (an enzyme that breaks down neurotransmitters at the synapse). Resulting in higher levels of neurotransmitters such as serotonin, dopamine and noradrenaline
• it's not just high levels of serotonin that have been implicated in offending behaviour, Higley et al 1996 suggests that low levels of serotonin play a role in aggressive behaviour
• Higley et al researched the relationship between serotonin levels and behaviour in monkeys.

  • they measured serotonin levels in the monkeys and separated them into high, mid-high, mid-low and low serotonin groups
  • 11/49 monkeys died over the observation due to aggressive behaviour and risk taking
  • all of these had low serotonin levels. those with low serotonin also had more scars and were observed more aggressive
• much research has been focused on the limbic system, which is a primitive brain area and includes structures such as amygdala which has been linked to emotion
• research has often focused on people diagnosed with antisocial personality disorder. referred to as psychopaths, they have problems processing emotions and empathy. This leads to a lack of remorse or guilt when they harm others
• Kent et al 2001 used FMRI scanning to study brain activity in criminal psychopaths during an emotion-based task

  • criminal psychopaths showed much less activity in the limbic system than non-psychopaths and non-criminal controls
• Raine et al 1997 studied murderers who were found not guilty by reason of insanity

  • compared to controls, they found abnormal asymmetries in the limbic system in murderers, especially the amygdala (with reduced activity on the left, increased on the right).
• Raine cited 71 brain imaging studies that show murderers and psychopaths have reduced functioning in the prefrontal cortex
• the prefrontal cortex is involved in managing emotion and control of behaviour, so reduced activity would lead to impulsive behaviour