Basal ganglia and Schizophrenia

Question 1

Define schizophrenia

Answer 1

a psychotic psychiatric disorder involving in the disturbance in the relation between thought, emotion, and behaviour, leading to faulty perception, inappropriate actions and feelings, withdrawal from reality and personal relationships. (or words to that effect)

Question 2

What are the positive symptoms of schizophrenia?

Answer 2

• Disorganisation of thoughts/speech
• Hallucinations
• Delusions

Question 3

What are the negative symptoms of schizophrenia?

Answer 3

Characterised by behavioural deficits - the 4 A’s:

• Avolition (lack of energy)
• Alogia (reduction in the amount or content of speech)
• Anhedonia (inability to experience pleasure)
• Asociality (severe impairment in social relationships)

Question 4

What are the 3 DSM IV categories of schizophrenia?

Answer 4

• Disorganised schizophrenia:
  Disorganised and flat speech
  General disruption of behaviour
• Catatonic schizophrenia
  Prolonged motor immobility that alternate with periods of excitability
• Paranoid schizophrenia
  Involves the presence of prominent delusions

Question 5

What is the brain pathology of schizophrenia seen in neuroimaging

Answer 5

• Reduced volume of temporal and frontal cortex
• Enlarged ventricles reflecting loss of brain cells
• Hypoactivation within prefrontal cortex

Question 6

What are the neurotransmitters implicated in SZ?

Answer 6

Dopamine, Glutamate and Seratonin

Question 7

______ Hyperactivity = Positive Symptoms

______ Hypoactivity = Negative Symptoms

Answer 7

Mesolimbic Hyperactivity = Positive Symptoms

Mesocortical Hypoactivity = Negative Symptoms

Question 8

What are the main models of modelling SZ in rodents?

Answer 8

• Transgenic
• Pharmacological (drugs of abuse)
• Lesions (dopamine depletion or foetal development disruption)
• Social manipulation (isolation)

Question 9

Explain the DISC-1 and Neuregulin genetic hypothesis of SZ and the evidence for this in animal studies

Answer 9

• Abnormalities of DISC-1 or neureglin genes
• disc1 and nrg1 function in controlling development of oligodendrocytes and neurones from olig2-expressing precursor cells
• Abnormalities cause neuronal disconnectivity
• Rats with knockdown of DISC-1 or increased levels of NRG-1 had impaired ability to undergo pre-pulse inhibition - showing reduced ability to filter sensory information