biological explanations

• • One biological explanations is schizophrenia is passed through genes
  • while the rate of schizophrenia in the general population is 1% if a parent has it there is 12% and two it increases to 40%
  • there have been different canditate genes
  • ripke found 108 seperate genetic variations were associated with increased risk of schizophrenia
• biochemical factors- dopamine

  • high levels or activity of dopamine in the subcortex, resulting in positive symptoms
  • caused by abnormal number of dopamine receptors, so more dopamine binds to post synaptic receptor sites, For example, an excess of dopamine receptors in Broca’s area might be responsible for auditory hallucinations.
  • , The negative symptoms of schizophrenia are thought to arise from abormal levels (high or low) deficit of dopamine in areas of the prefrontal cortex
• Neural correlates

  patterns of structure or activity in the brain that occur in conjunction with schizophrenia
• • People with schizophrenia have abnormally large ventricles in the brain . Ventricles are fluid filled cavities (i.e. holes) in the brain that supply nutrients and remove waste. This means that the brains of schizophrenics are lighter than normal. The ventricles of a person with schizophrenia are on average about 15% bigger than normal 
• specific brain areas

  • pre-frontal cortex- main area involved in executive control (eg.planning reasoning), impaired in schixo patients
  • hippocampus, deficits in nerve connections with this and pfc correlates with deficits in working memory performance
  • hippo damage also linked to dopamine release indirectly affceting processing of info in pfc
  • schixophrenic patients show less activity in the ventral striatum-the largest structure in teh basal ganglia and associated with negative symptoms like avolition
• grey and white matter

  • reduced grey matter in frontal and temporal lobes
  • enlarged ventricles- 5% larger than normal, may be a result of tissue damage or poor brain development
  • reduced white matter pathways especially in neural pathway between pfc and hippo (affects information processing)