Neural correlates

• What is the definition of neural correlates in terms of schizophrenia?

  Patterns or structures in the brain that occur in conjunction with an experience and may be implicated in the origins of that experience. The dopamine hypothesis occurs with a schizophrenic experience. As they occur simultaneously this could lead us to believe that the patterns observed are implicated in causing schizophrenia
• What is avoition as an explanation for schizophrenia?

  Avoition which involves motivation, has been associated with one of the main reward centres in the brain. The ventral striatum is crucial in the anticipation of reward. Juckel et al (2006) measured activity levels here and found lower levels of activity in schizophrenics compared to controls
• What is it called when an individual has increased or decreased levels of dopamine?

  Increased levels in Broca’s area and sub cortex = hyperdopaminergia

  Decreased levels in pre-frontal cortex = hypodopaminergia
• What is dopamine and how does it differ in individuals with schizophrenia?

  • Dopamine is a chemical substance (neurotransmitter) manufactured in the brain that transmits messages between neurons (brain cells)
  • Dopamine appears to work differently in patients of schizophrenia
  • Dopamine is particularly important in the functioning of several brain systems that may cause symptoms of schizophrenia - in particular the cortex and sub-cortex.
• What does the original dopamine hypothesis state?

  The original dopamine hypothesis claims that an excess of the neurotransmitter dopamine in certain regions of the brain is associated with the positive symptoms of schizophrenia

  • Research suggests that schizophrenics are thought to have abnormally high numbers of D2 receptors on receiving neurons, resulting in more dopamine binding and therefore neurons firing

  
• What does the revised dopamine hypothesis state?

  David et al (1991):

  -Excess of dopamine in the mesolimbic pathway

  -Positive symptoms

  -Deficit of dopamine in areas of the prefrontal cortex :

   - Area responsible for thinking, decision making etc

   - Negative symptoms
• What is some evidence for the revised dopamine hypothesis?

  Neural imaging - Patel et al (2010)

   - Used PET scans and found lower dopamine levels in 

     dorsolateral prefrontal cortex of schizophrenics

     compared to normal controls