Neural

• What are neural correlates

  Patterns of structure or activity in the brain that occur in conjunction with an experience and may be implicated in the origins of that experience
• What is the Original Dopamine Hypothesis

  An excess of dopamine (hyperdopaminergia) in certain regions of the brain may cause symptoms of schizophrenia
• What is the Updated Dopamine Hypothesis

  Kenneth Davies et al (1991)

  Lack of dopamine (hypodopaminergia) in the prefrontal cortex (responsible for thinking) could explain cognitive problems i.e. negative symptoms
• Davies et al findings of fMRI scans of schizophrenic brains show…

  • Higher levels of activity involving neurons that transmit dopamine (fire more often) in the sub cortex area compared to the controls brains
  • Also show lower levels of activity involving neurons that transmit dopamine in prefrontal cortex
• How do brain structure differences lead to development of schizophrenia

  Abnormality in the Ventral Striatum (region in the brain believed to be involved in the anticipation of reward and motivation) may be involved in the development of avolition
• What did Juckel et al find about brain structure differences and schizophrenia

  Lower levels of activity involving the VS of schizophrenic patients compared to controls

  • negative correlation between activity involving the VS and the severity of negative symptoms

  = Suggests activity involving the VS is a neural correlate of negative symptoms of schizophrenia
• Neural Correlates of Positive Symptoms

  Allen et al (2007)

  • scanned brans of patients experiencing auditory hallucinations and compared them to a control group
  • both groups had to identify pre-recorded speech as their own voice or others
  • Lower activation levels in the superior temporal gyrus and anterior cingulate gyrus were found in the hallucination group

  = suggests, reduced activity involving these two areas of the brain is a neural correlate of auditory hallucinations
• Strength of neural explanations- Research has shown that drugs that increase levels of dopamine produce schizophrenic symptoms

  This supports that dopamine hypothesis as it shows a causal link between increased dopamine activity and psychotic symptoms
• Limitation - Clozapine is the most effective drug at reducing schizophrenic symptoms- it acts on serotonin as well as dopamine

  This suggests that dopamine is not the sole factor, as the effectiveness of clozapine points to the involvement of serotonin, challenging the exclusivity of the dopamine hypothesis
• Strength- An excess number of dopamine receptors have been found in Broca’s area, which is linked to speech production and auditory hallucinations

  This finding directly ties dopamine dysregulation to specific symptoms of schizophrenia