Neurobiology of Psychosis Flashcards
patient believes that their parents are trying to poison them because the government are controlling them. Which psychopathology term is most appropriate?
paranoid delusion
patient believes that news articles on the television about world leaders’ phones being tapped are actually talking about themselves as they holds important government information- what term describes this
ideas of reference
what is a functional hallucination
where the hallucination does not occur in the absence of a stimulus but are triggered by a stimulus in the same modality as the hallucination and can co occur with it
e.g. When Brian listens to the radio he can hear voices from elsewhere in the room telling him he must not think about the military information he has been given
what is heritability
proportion of observable differences in a trait between individuals in a population that is due to genetic differences
what is the inheritance of schizophrenia
multifactorial
does a childhood viral CNS infection increased risk of schizophrenia
yes by 50%
what does a brain look like in a patients with schizophrenia who has a poor prognosis
reduced frontal lobe volume
reduced frontal lobe grey matter
enlarged lateral ventricle volume
what brain abnormalities are seen in schizphrenia
reduction in gray matter in the: temporal cortex medial temporal lobe orbitofrontal cortex parietal cortex basal ganglia
white matter- abnormal neural integration (increased fractional anisotrophy= reduced healthy white matter tracts)
what causes gray matter abnormalities in schizophrenia
reduced arborisation (branching) same number of neurones just abnormal connections in both gray and white matter
what is the dopamine hypothesis of schizophrenia
drugs which release dopamine in the brain or D2 receptors agonists produce a psychotic state
in schizophrenia there is overactivity of dopamine pathways in the brain
how do amphetamines affect schizophrenia symptoms
can worsen them
antagonists of what are used to treat the symptoms of schizphrenia
dopamine receptor antagonists
what are the dopaminergic pathways, what do they do and what areas do they involve
nigrostriatal- extrapyramidal motor system (substantia nigra-> dorsal striatum)
mesolimbic/ cortical - motivation and reward systems (ventral tegmental area-> amygdala, hippocampus, frontal cortex, nucleus accumbens)
tuberoinfundibular- control of prolactin release
what are the two subtypes of dopamine receptors
D1 receptor family (D1 and 5)
D2 receptor family (D2,3,4)
what do D1 receptors do
stimulate cAMP
what do D2 receptors do
inhibit adenylyl cyclase
inhibit voltage activated Ca2+ channels
opens K+ channels
what type of dopamine receptor is most abundant
D1
where are D1 receptors found
neostriatum, cerebral cortec, olfactory tibercle, nucleus accumbens
where are D2 receptors found
neostriatum, olfactor tubercle, nucleus accumbens, pituitary gland
where are D3 receptors found
nucleus accumbens, island of calleja
where are D4 receptors found
midbrain, amygdala
where are D5 receptors found
hippocampus, hypothalamus
which dopamine receptors are found within the limbic ans striatal areas
D1 and 2
what neurobiology causes psychosis
subcortical dopamine hyperactivity
what neurobiology caiuses negative and cognitive symptoms
mesocortical dopamine hypoactivity
what other neurotransmitters are suggested to be involved in schizophrenia
glutamate- altered NMDA receptor expression
serotonin- reduced binding potential in frontal cortex
what genes cause brain pathology in schizphrenia
neuregulin- a signalling protein that mediates cell-cell interactions and plays critical roles in the growth and development of multiple organ systems
dysbindin- essential foe adaptive neural plasticity
DISC-1 - involves in neurite outgrowth and cortical development through its interaction with other proteins
what is a typical antipsychotic
works primarily though inhibition of D2 receptors
what symptoms are typical antipsychotics more likely to cause
extrapyramidal symptoms
