T3 L4 Schizophrenia Flashcards
What is the risk of schizophrenia in monozygotic twins??
Up to 50%
What changes could a variation in the sequence of a gene lead to?
Interaction that cell has with other cells in the connections & cell assemblies that develop
How such assemblies & networks operate as functional systems
What issues at birth can increase the likelihood of schizophrenia?
Obstetric complications
Prenatal infections
Nutritional deficiency
Environmental
What issues during adolescence can increase the likelihood of schizophrenia?
Adverse life events
Substance abuse
What is the neuropathology that occurs in schizophrenia?
Ventricular enlargement
Reduced brain volume in temporal lobes, frontal lobes & subcortical structures
Cytoarchitectural differences in cortex & hippocampus
Increase in paracingulate sulcus
What is the paracingulate sulcus involved in?
Monitoring reality
Morphology associated with hallucinations
What is the Wisconsin card sorting task?
Told to match sample but not how to match it
Sensitive to executive dysfunction, set shifting, cognitive flexibility
Given a different rule for the second set
Why do those with schizophrenia struggle with the Wisconsin card sorting task?
They lack cognitive flexibility
What did Lewis propose?
In people who later develop schizophrenia, chandelier cells fail at some crucial task of cultivating pyramidal cells during childhood or early adolescence
What does normal cortical development involve?
Proliferation
Migration
Arborisation
Myelination
Describe the theta rhythm
4-8Hz 250-125ms Hippocampus Fire at peaks Important for coordination & organising faster oscillations in other areas of the brain Long range
Describe the alpha rhythm
10Hz
100ms
Eyes closed
Describe the beta rhythm
15-30Hz
67-33ms
Throughout brain, specifically in motor system
Describe the gamma rhythm
30-80Hz 17-13ms Important for cognition Short range Depend on theta rhythm
What is the evidence for the dopamine hypothesis?
Typical antipsychotic drugs
DA agonists
Why do typical antipsychotic drugs provide evidence for the dopamine hypothesis?
D2 receptor antagonists
Prevent positive symptoms
Why do DA agonists provide evidence for the dopamine hypothesis?
Cocaine, amphetamine, L-DOPA can cause positive symptoms of schizophrenia at large doses
Drug-induced psychoses can be treated with D2 antagonist antipyschotic drugs
Describe the D1 receptor family
Gs coupled
D1
D5
What structures are involved in D1?
Caudate-putamen
NAcc
Olfactory
Tubercule
What structures are involved in D5?
Hippocampus
Hypothalamus
Describe the D2 receptor family
Gi coupled
D2
D3
D4
What structures are involved in D2?
Caudate-putamen
NAcc
Olfactory
Tubercule
What structures are involved in D3?
Olfactory Tubercule Hypothalamus NAcc cerebellum
What structures are involved in D4?
Frontal cortex
Medulla
Amygdala
Midbrain
What are the parkinsonian-like symptoms?
Slow movement
Lack of facial expression
What are the tar dive dyskinesia symptoms?
Slow, fault movements
Why don’t atypical antipsychotics have the same extrapyramidal side effects?
They have a lower activity at D2 receptor
Give some examples of atypical antipsychotics
Clozapine
Risperidone
Olanzapine
What are the side effects of clozapine?
Weight gain Sedation Hypersalivation Tachycardia Hypotension Neutropenia
What is the evidence for the glutamate hypothesis?
1) PCP is an NMDA receptor antagonist that causes positive, negative & cognitive symptoms of schizophrenia
2) Genetically engineered mice with fewer NMDA receptors are more antisocial and have difficulties in learning and memory.
What are the neurocognitive deficits of schizophrenia?
Enduring symptoms of this disease Lower IQ Attentional deficits Working memory Planning & information processing deficits
What is the stroop task?
Say colour of word, don’t read what word says
Those with schizophrenia are slower and less accurate as they find it difficult to inhibit other contextual information
