mental disorders

Question 1

dopamine hypothesis schizophrenia

Answer 1

too much dopamine in mesolimbic pathway –> positive symptoms

too little dopamine in mesocortical pathway –> negative symptoms

Question 2

glutamate hypothesis schizophrenia

Answer 2

glutamate is excitatory neurotransmitter.
Reduced NMDA (glutamate receptor) receptors in PM

hypo function of NMDA in GABAergic inhibitory interneurons –> dimihsed inhibitory influences on neuronal function –> hyperstimulated cortical neurons

Question 3

interactions between glutamatergic and dopaminergic pathways in schizophrenia

Answer 3

hypo function of NMDA receptors in inhibitory neurons –> less secretion of GABA neurotransmitter –> less inhibition of glutamatergici neurons –> increased activation of dopaminergic neurons

Question 4

neurodevelopmental model of schizophrenia

Answer 4

altered excitatory-inhibitory balance

reduced elaboration inhibitory pathways and excessive pruning of excitatory pathways

Question 5

neurotransmitters and schizophrenia

Answer 5

dopamine (D2 antagonists block positive symptoms)
glutamate (NMDA antagonists produce positive symptoms)
GABA (reduced synthesis and reuptake)
Ach (decreased cholinergic receptors hippocampus, thalamus and striatum)
serotonin

Question 6

aetiology major depressive disorder - abnormality in neural circuit

Answer 6

excitation-inhibition palace

depressed patients show lower plasma, CSF & brain GABA
when GABA inhibitory signalling decreased, the brain tries to balance out and also decreases excitatory glutamate signals , reducing overall brain activity