Neurobiology of psychosis

Question 1

What are the following associated with? :

• reduced frontal lobe volume
• reduced frontal lobe grey matter
• enlarged lateral ventricle volume

Answer 1

Associated with a poor prognosis

Question 2

Schizophrenia is associated in changes of which matter in the brain?

Answer 2

Associated with changes in the grey matter

• changes are widely distributed
• changes are present early in the disease (and likely premorbidly)
• Grey matter reductions due to reduced aborisation and not neuron loss
• grey matter reductions likely PROGRESSIVE in the initial years of the illness

Question 3

Good way to image the drug?

Answer 3

Diffusion tensor imaging (DTI)

Question 4

What does fractional anisotropy mean? (in terms of diffusion tensor imaging)

Answer 4

Higher numbers mean healthy white matter tracts

(but higher FA correlates with psychotic symptom severity. Myelin abnormalities may be a cause of the anisotropy abnormalities)

Question 5

What does mean diffusivity mean? (in terms of diffusion tensor imaging)

Answer 5

Higher numbers mean LESS healthy white matter tracts

Question 6

Why is it not possible to diagnose schizophrenia by radiology?

Answer 6

Not possible because of abnormal variation i.e. the AVERAGE brain of a patient with schizophrenia is smaller than the AVERAGE brain in a healthy control (average etc blah blah)

Question 7

Factors in pregnancy which could lead to schizophrenia development of that baby?

Answer 7

• 2nd trimester viral illness

- Obstetric problems: pre-eclampsia. fetal hypoxia, emergency caesarian section

Question 8

Dopamine and the brain

Answer 8

It is assumed that schizophrenia is related to overactivity of dopamine pathways

Question 9

How does amphetamine act on the dopamine pathway?

Answer 9

Amphetamine releases dopamine in the brain

Question 10

What does the D1 receptor family stimulate? (D1 and D5)

Answer 10

Stimulates cAMP

Question 11

What does the D2 receptor family do? (D2, D3, D4)

Answer 11

• Inhibit adenyl cyclase
• Inhibit voltage-activated Ca2+ channels
• Open k+ channels

(D2 agonists produce psychotic symptoms in ppl)

Question 12

Where would you find D1 and D2 receptors in the brain?

Answer 12

Limbic and striatal areas

Question 13

Bromocriptine

Answer 13

D2 agonist

Question 14

Raclopride

Answer 14

D2 antagonist

Question 15

Haloperidol

Answer 15

D2 antagonist

Question 16

What is clozapine?

Answer 16

D4 antagonist

Question 17

What is neuregulin?

Answer 17

A signalling protein that mediates cell-cell interactions

-plays CRITICAL ROLE IN THE GROWTH AND DEVELOPMENT of multiple organ systems

Question 18

What is Dysbindin essential for?

Answer 18

Essential for adaptive neural plasticity

Question 19

What is DISC-1 involved in?

Answer 19

Involved in neurite outgrowth and cortical development through its interactions with other proteins