Neural correlates

Question 1

How does dopamine relate to Sz?

Answer 1

• research has identified neural correlates (Brian structure/function) associated with Sz, best known is dopamine

Question 2

What is the Original Dopamine Hypothesis?

Answer 2

• based on discovery drugs used to treat Sz (antipsychotics - reduce DA) caused symptoms similar to those with Parkinson’s disease (associated with low DA)
• Therefore Sz may be associated with high DA (hyperdopaminergia ‘hyper’ ‘high’) in subcortical levels of the brain
• excess of DA receptors in pathways from the subcortex to Broca’s area (responsible for speech production) may explain speech poverty/hallucinations.,

Question 3

What is the updated version of the dopamine hypothesis?

Answer 3

• Davis et al proposed the addition of cortical hypodopaminergia (low DA in cortex)
• low DA in prefrontal cortex (thinking) could explain cognitive issues (negative symptoms)
• been suggested that cortical hypodopaminergia leads to subcortical hyperdopaminergia - both high and low levels of DA in different brain regions
• explaining links between abnormal DA levels and symptoms, also explain origins of abnormal DA function. Both genetic variations and early experiences of stress make someone more sensitive to cortical hypodopaminergia and hence subcortical hyperdopaminergia

Question 4

How is the genetic explanation biologically reductionist?

Answer 4

• environmental factors e.g birth complications and smoking THC-rich cannabis in teenage years
• Also childhood trauma Morkved et al 67% of people with Sz and related psychotic disorders reported childhood trauma as opposed to 38% of a matched group with non-psychotic mental health issues

Question 5

What evidence supports neural correlates as an explanation of Sz?

Answer 5

• Curran discovered amphetamines increase DA and therefore worsen symptoms in those with Sz and induces symptoms in those without

Question 6

How does glutamate reduce the validity of dopamine as an explanation for Sz?

Answer 6

• glutamate has a central role, post-mortem and live scanning found raised levels of glutamate in several brain regions (McCutcheon), there may be other neurotransmitters