Biological Exp Amygdala

Question 1

What is the initial dopamine hypothesis?

Answer 1

The hypothesis proposes that the brain of SZ patients produce more dopamine than normal brains (hyper dopaminergia). It is this increased amount of dopamine that is responsible for some of the symptoms of SZ. It was found that increased dopamine levels in Parkinson’s patients led to positive symptoms of SZ. Thsi explanation was said to be too simple as reducing dopamine for rid of positive symptoms but not negative

Question 2

What is the revised dopamine hypothesis? (2 pathways)

Answer 2

The overactivity of the Mesolimbic pathway
The mesocortical pathway dysfunction

Question 3

What is the overactivity of the Mesolimbic pathway

Answer 3

Pathway runs from VTA to nucleus accumbens.
Too much dopamine in the pathway (neurons firing too often or too quickly)
Causes overstimulation leading to the positive symptoms.
Antipsychotic drugs that reduce dopamine transmission (d2 receptors) target this pathway and reduce the positive symptoms

Question 4

What is the mesocortical dsyfunction pathway?

Answer 4

Pathways runs from VTA to frontal lobe.
Pathway is important for emotional response and motivation. Not enough dopamine in this pathway (hypodopaminergia)
In this pathway (d1 receptor) leads to negative symptoms of SZ