Biological explanation: Neural correlates of Schizophrenia

• Neural correlates of schizophrenia

  Neural correlates of schizophrenia propose there is a correlation between brain structure/function and symptoms of schizophrenia. One

  neural correlate of schizophrenia is the dopamine hypothesis.
• The dopamine hypothesis

  The dopamine hypothesis focuses on the role that dopamine plays in the development of schizophrenia. According to this theory, schizophrenia can result from:

  • Hyperdopaminergia in the subcortex

  • Hypodopaminergia in the cortex
• Hyperdopaminergia in the subcortex: What does it refer to?

  When there is too much activity of dopamine in subcortical areas

  of the brain (i.e. areas beneath the outer cortex of the brain).
• Hyperdopaminergia in the subcortex: Why does it occur in people with schizophrenia?

  It results from a higher number of D2 receptors on the dendrites

  of neurons in the subcortical areas of schizophrenics’ brains.
• Hyperdopaminergia in the subcortex: How can it explain the symptoms of schizophrenia?

  A higher number of D2 receptors means more dopamine can bind

  and exert its excitatory effects. This will mean that the neurons in

  subcortical areas will fire more than usual. As a result, such over-

  activity is proposed to cause the positive symptoms of schizophrenia such as hallucinations and delusions.
• Hypodopaminergia in the cortex: What does it refer to?

  When there is too little activity of dopamine in the outer cortex

  of the brain. This is particularly evident in the prefrontal cortex.
• Hypodopaminergia in the cortex: Why does it occur in people with schizophrenia?

  It results from the reduced binding of dopamine to D1 receptors

  in the prefrontal cortex of schizophrenics’ brains.
• Hypodopaminergia in the cortex: How can it explain the symptoms of schizophrenia?

  • The prefrontal cortex is involved in executive control and decision-making.
  • Reduced activity in this area is linked to negative symptoms of schizophrenia.
  • Avolition (difficulty in goal-directed activities) is explained by reduced prefrontal cortex activity.
  • The prefrontal cortex is located near Broca's area in the frontal lobe.
  • Reduced activity near Broca's area contributes to speech poverty, a negative symptom of schizophrenia.
• Evaluate neural correlates of schizophrenia

  • have led to practical applications in the treatment of schizophrenia
  • there are difficulties establishing cause and effect
  • it may not provide a complete explanation
  • it is too biologically reductionist