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Neuroscience Y3S1 > Schizophrenia > Flashcards

Schizophrenia Flashcards

1
Q

What is the lifetime risk of schizophrenia? (1)

A

0.7-1%

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2
Q

Fill the gaps relating to schizophrenia. (3)

Schizophrenia has a ………………. basis, but ………………… and …………………. factors also play a big part in its emergence.

A

genetic

environmental

social

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3
Q

Given that there is no cure for schizophrenia, describe the long-term outcomes for patients. (3)

I.e. 30% of patients…

A

About 30% of patients can live with their delusions and hallucinations

About 30% to 40% of patients respond well to medication and/or CBT

About 30% to 40% of patients remain treatment-resistant

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4
Q

What is the risk for schizophrenia if a parent has it? (1)

A

6%

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5
Q

What is the risk for schizophrenia if a sibling has it? (1)

A

9%

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6
Q

What is the risk for schizophrenia if an identical twin has it? (1)

A

48%

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7
Q

Is schizophrenia onset typically earlier in men or women? (1)

A

Men

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8
Q

Is schizophrenia more prevalent in men or women? (1)

A

Men

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9
Q

Give two factors regarding place/time of birth that increase schizophrenia risk. (2)

A

Winter birth

Born in urban environment

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10
Q

Give five potential infectious factors which may increase schizophrenia risk. (5)

A

Influenza

Respiratory

Rubella

Poliovirus

CNS

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11
Q

Give 5 prenatal risk factors which may increase risk of Schizophrenia. (5)

A

Famine

Bereavement

Flood

Unwantedness

Maternal depression

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12
Q

Give 5 obstetric factors which may increase risk of schizophrenia. (5)

A

Rh incompatibility

Hypoxia

CNS damage

Low birth weight

Pre-eclampsia

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13
Q

Inflammation in the developing brain is thought to lead to both autism and schizophrenia.

Describe the differences between neuroinflammation which will likely lead to autism vs schizophrenia. (2)

A

Autism = persistent, chronic inflammation

Schizophrenia = inflammation which subsides (becomes latent)

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14
Q

Describe how inflammation in the developing brain (which subsides) may lead to schizophrenia-like symptoms later in life. (1)

A

Microglia are primed to react stronger to the next insult/injury later in life.

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15
Q

Very briefly describe the dopamine hypothesis of schizophrenia. (2)

A

Overstimulation of dopaminergic pathways

in cortical and limbic areas.

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16
Q

Very briefly describe the glutamate hypothesis of schizophrenia. (1)

Give a piece of evidence for this hypothesis. (1)

A

NMDA receptor hypofunction

Evidence: ketamine blocks NMDA receptors and chronically can lead to psychotic symptoms

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17
Q

Give four ‘components’ or ‘factors’ in the immunological theory of schizophrenia. (4)

A

Abnormal immunological findings in subgroups of schizophrenic patients

Neurodegeneration

Viral infections

Microglial activation

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18
Q

Describe the 2 hit hypothesis of schizophrenia. (2)

A

2 separate life stressors cause the symptoms of schizophrenia

(Usually an early stressor during early development, then a subsequent one).

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19
Q

Describe how a ‘life stressor’ in early development affects dopamine in the brain. (1)

A

There will be altered dopamine development due to genetic and/or environmental risk factors.

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20
Q

Give five potential life stressors which may affect dopamine development in early/prenatal life. (5)

A
  • Maternal infection
  • Foetal neuroinflammation
  • Hypoxia
  • CNS damage
  • Low birth weight
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21
Q

Give three potential life stressors which may affect behaviour and dopamine function in childhood. (3)

A

Trauma

Maternal separation

War/famine

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22
Q

Fill the gaps relating to the development of schizophrenia. (4)

Life stressors in prenatal life, early life, or childhood, may cause …………………. behavioural abnormalities, and this could be due to the early effects of …………………… dysfunction and extraneous effects of ………………………. or …………………….. insults.

A

subtle

dopamine

genetic

environmental

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23
Q

Give six symptoms that may be experienced in the ‘prodrome’ to schizophrenia, usually in adolescence. (6)

The prodrome will usually be accompanied by clear abnormalities in which neurotransmitter system? (1)

A

Anhedonia

Social withdrawal

Hallucinations

Paranoia

Anxiety

Insomnia

  • Clear dopaminergic abnormalities
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24
Q

Disease onset in schizophrenia is usually accompanied by acute psychosis.

Describe how dopamine changes at this time. (1)

A

Dopaminergic flux

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25
Q

Schizophrenia treatment is able to stabilise which symptoms, mediated by which neurotransmitter? (2)

A

Dopamine-based

psychotic symptoms

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26
Q

Schizophrenia treatment typically does not treat negative symptoms, and these symptoms tend to persist.

Hypothesise why these symptoms might persist. (1)

A

They are caused by the consequences of altered dopamine development on glutamate and GABA.

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27
Q

Name an animal model of schizophrenia that is not genetic. (1)

A

Maternal separation

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28
Q

Describe the maternal separation animal model of schizophrenia. (3)

A

Take pups away from mothers at P9 for 24 hours

Mother doesn’t take care of pups as well when they’re returned to the cage

Schizophrenic symptoms shown in adulthood

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29
Q

Give four symptoms that rodents typically show in adulthood following the maternal separation model of schizophrenia. (4)

A

Anxiety

Depression

Changes to prepulse inhibition

Social withdrawal

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30
Q

Give five negative symptoms of schizophrenia. (5)

A

Social withdrawal

Depression

Apathy (lack of enthusiasm)

Avolition (lack of motivation)

Anhedonia (reduced experience of pleasure)

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31
Q

Name two positive symptoms of schizophrenia. (2)

A

Hallucinations

Delusions

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32
Q

What is a hallucination? (1)

What is the most common type of hallucination in schizophrenia? (1)

A

A false perception

Auditory (patients report hearing people talking about them)

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33
Q

What is a delusion? (1)

Describe two common delusions in schizophrenia. (2)

A

A persistent bizarre or irrational belief.

Commonly, patients report being persecuted

or believe wild conspiracy theories.

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34
Q

What is a bizarre delusion? (1)

A

Imagining impossible situations

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35
Q

What is a non-bizarre delusion? (1)

A

Imagining possible situations

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36
Q

What is a mood-congruent delusion? (1)

A

Occurs when in a manic or depressive state.

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37
Q

What is a mood-incongruent delusion? (1)

A

Happens without a particular mood’s influence

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38
Q

What is a Capgras delusion? (1)

A

The belief that a loved one like a mother or sibling has been replaced by an imposter.

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39
Q

What is a Cotard delusion? (1)

A

A belief that you are dead or your body has disintegrated or no longer exists.

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40
Q

What is a delusion of persecution? (1)

A

The belief that you are being unfairly mistreated, harmed, or watched. The conviction is so strong that the person may seek help from the authorities.

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41
Q

What is the most common delusion that people experience? (1)

A

Delusion of persecution

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42
Q

What is a delusion of reference? (1)

A

The belief that something like a poster, a song, or a billboard advertisement has a direct message or a hidden meaning for you. A person with this delusion may see a sign that has nothing to do with them but they believe the message is directed at them specifically.

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43
Q

What is the difference between a hallucination and a delusion? (2)

A

Delusions are unshakeable beliefs (thoughts) that are not real.

Hallucinations are sensory experiences — such as hearing, seeing, smelling, or feeling things that are not really there.

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44
Q

What is a delusion of control? (1)

A

The belief that an external entity (a person or a force) is controlling your thoughts, behaviours, and impulses.

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45
Q

What is a delusion of grandeur? (1)

A

Exaggerated or inflated self-belief regarding power, fame, knowledge, skill, talent, or strength.

46
Q

What is a delusion of thought manipulation? (1)

A

The belief that thoughts have been inserted into your mind or are being broadcasted to others.

47
Q

What is an erotomanic delusion? (1)

A

The belief that someone, usually someone famous or otherwise out of reach, is in love with you.

48
Q

Describe the auditory verbal hallucinations that are highly characteristic of schizophrenia. (1)

A

Typically take the form of voices speaking either to or about an individual.

49
Q

Fill the gaps relating to schizophrenia. (4)

……………………. medications markedly reduce auditory verbal hallucinations, suggesting ……………………. involvement in these phenomena.

Nevertheless, the majority of patients with AVHs show some persistence of their hallucinations even while receiving this medication, indicating that other systems (e.g. …………………… and ……………………) may also contribute.

A

Antipsychotic

dopaminergic

glutamate

GABA

50
Q

Suggest a piece of evidence supporting dopaminergic involvement in auditory verbal hallucinations in schizophrenia. (1)

A

Antipsychotic medications markedly reduce AVHs.

51
Q

Suggest a piece of evidence supporting non-dopaminergic involvement in auditory verbal hallucinations in schizophrenia. (1)

A

The majority of patients with AVHs show some persistence of their hallucinations even while receiving antipsychotic medication.

52
Q

Give two general changes to the auditory cortex that are associated with auditory verbal hallucinations in schizophrenia. (2)

A

Volume loss

Functional hyperactivity

53
Q

Local pathology within which brain region may contribute to auditory verbal hallucinations in schizophrenia? (1)

A

Auditory cortex

54
Q

Fill the gaps relating to auditory verbal hallucinations in schizophrenia. (2)

Impaired ……………………. input to the auditory cortex may have an important role, as AVHs are observed during ………………………….

A

thalamocortical

sensory deprivation

55
Q

Deficits in which sensory system strongly contribute to the overall psychosocial dysfunction in schizophrenia. (1)

A

Auditory system

56
Q

Fill the gaps relating to schizophrenia. (15)

One key process that is affected by impaired sensory capabilities in schizophrenia is the ability to interpret the ……………………. of verbal communications.

In Western languages, tonal transitions do not contribute strongly to the perception of …………………………………… but do convey non-verbal information such as ………………. or ………………….

For example, happiness is typically accompanied by an increase in both the ……………………… and …………………………. in speech, whereas sadness is conveyed by reductions in …………………….. and …………………………..

Consistent with other auditory findings, Mandarin-speaking individuals with schizophrenia show notable deficits in the ability both to identify and to discriminate words that are …………………………… but ……………………………

Other types of non-verbal information, such as attitudinal prosody (………………………) are also conveyed by subtle shifts in the …………………. In schizophrenia, deficits in tone matching strongly correlate with deficits in prosodic processing, including both ………………….. and …………………….. prosody. These deficits can lead to impairments in …………………………

A

prosody

individual speech sounds (phonemes)

emotion

attitude

base pitch

degree of pitch variation

base pitch

pitch variability

phonetically identical

tonally distinct

sarcasm

pitch

emotional

attitudinal

social functioning

57
Q

People with schizophrenia struggle to interpret the prosody of verbal communications.

Give three examples of ‘prosodic features’ of speech. (1)

A

Intonation

Syllabic stress

Rhythm

58
Q

Describe how the tone-matching experiment works when investigating schizophrenia. (3)

A

Tones are presented sequentially, and subjects must report whether the second tone is the same or different from the first, or whether it is higher or lower in pitch.

The interval between the tones was either silent (easy condition) or auditory stimuli were played in between the two tones (difficult condition).

In addition, subjects were either asked to stay silent between tones (no distraction) or asked to count aloud (distraction).

59
Q

The ability to match tones following a brief delay depends on what, in both individuals with schizophrenia and control subjects? (1)

A

Formation of an echoic memory trace

60
Q

How long does an echoic memory trace typically last in both schizophrenic and control subjects? (1)

A

10-30 seconds

61
Q

Are people with schizophrenia typically better or worse than controls at a tone-matching experiment? (1)

A

Worse

62
Q

Fill the gaps relating to the tone matching experiment in schizophrenia. (4)

When the performance of schizophrenic patients in the easy discrimination task was compared with that of controls in the difficult condition, performance decay curves …………………….. over the 20‑second interval. This indicates that patients with schizophrenia have deficits primarily in the ……………………., rather than ……………………………., of sensory information. This is consistent with a pathology of the ……………………………..

A

overlapped

encoding

retention

primary auditory cortex

63
Q

Briefly describe the auditory pathway. (5)

*This kind of relates to schizophrenia

A

Auditory information ascends via the cochlear nucleus,

superior olivary complex,

and inferior colliculus

to the medial geniculate nucleus of the thalamus

and then to the auditory cortex.

64
Q

True or false? Explain your answer if necessary. (1)

Individuals with schizophrenia have intact performance on routine hearing tests or auditory brainstem responses.

A

True

65
Q

True or false? Explain your answer if necessary. (1)

Routine hearing tests and auditory brainstem responses are very informative about the existence of potential cortical-level dysfunction in schizophrenia.

A

False - individuals with schizophrenia have intact performance on routine hearing tests or auditory brainstem responses

66
Q

Describe one of the most common MRI alterations in schizophrenia. (1)

A

Reduced volume of the superior temporal gyrus.

67
Q

When are volume reductions in the superior temporal gyrus usually present in the time course of schizophrenia? (1)

What is the significance of this? (1)

A

Present before initial diagnosis

and therefore do not seem to be an artefact of medication or prolonged illness duration.

68
Q

Describe a piece of evidence supporting the fact that superior temporal gyrus grey matter volume reductions are specific to schizophrenia and not psychosis. (1)

A

Not found in bipolar disorder with psychosis

69
Q

True or false? Explain your answer if necessary. (1)

Superior temporal gyrus volume reductions in schizophrenia have been found to arise from extensive alcohol use in these patients.

A

False - STG volume reductions not induced by alcohol dependence

70
Q

Fill the gaps relating to schizophrenia. (3)

Grey matter alterations within the ……………………. are associated with the first ………………………. in adolescence in patients that later develop ………………………

A

auditory cortex

psychotic episode

schizophrenia

71
Q

Fill the gaps relating to schizophrenia. (2)

Immunocytochemical studies of the auditory cortex of patients with schizophrenia show a 27% reduction in ……………………………………. in deep layer 3 ……………………………….. cells.

A

dendritic spine density

supragranular pyramidal

72
Q

True or false? Explain your answer if necessary. (1)

In schizophrenia, reductions in spine density in the auditory cortex are caused by an overall loss of pyramidal neurones.

A

False - it is caused by a reduction in the number of spines per neuron

73
Q

Give two potential functional consequences of the loss of dendritic spine density in layer 3 of the auditory cortex in schizophrenia. (2)

A

Reduction in neuronal connectivity

Impaired pattern separation of inputs that represent different sound frequencies (disruption of sensory neural coding mechanisms)

74
Q

Give a possible explanation for the deficits in sound frequency discrimination seen in people with schizophrenia. (2)

A

Reduction in dendritic spine density in layer 3 of the auditory cortex

which could impair the pattern separation of inputs that represent different sound frequencies.

75
Q

Fill the gaps relating to schizophrenia. (4)

Although the medial geniculate nucleus has not been directly studied in post-mortem tissue of individuals with schizophrenia, one study showed that the density of …………………………………. boutons in the thalamocortical recipient layer of the primary auditory cortex (i.e. deep layer 3) was unchanged.
This shows that thalamocortical input to the auditory cortex is …………………………

However, a reduction in dendritic spine density in the supragranular cortical layers, are thus consistent with findings that indicate individuals with schizophrenia have intact ………………………………… but impaired ………………………………..

A

VGluT2-immunoreactive

intact

simple auditory detection thresholds

tone matching abilities

76
Q

True or false? Explain your answer if necessary. (1)

Input from the thalamus to the auditory cortex remains intact in patients with schizophrenia.

A

True

77
Q

Fill the gaps relating to schizophrenia. (7)

Proteomic analysis of 155 synaptic proteins in the primary auditory cortex tissue found that schizophrenia is associated with the altered expression of various ………………………….. signalling proteins.

The two most significantly reduced proteins were ……………….. and ………………, which are calcium-permeable subunits of …………………… receptors.

…………………….. protein levels were found to be unchanged. However, this does not rule out altered …………………………. status of the protein and thus altered ion channel functioning.

There was also a marked reduction in immunoreactivity for the ………………………., which is a regulator of dendritic plasticity in the auditory cortex of individuals with schizophrenia.

A

glutamatergic

GluR3

GluR4

AMPA

NMDAR

phosphorylation

microtubule-associated protein 2 (MAP2)

78
Q

Fill the gaps relating to schizophrenia. (6)

Reductions in …………………………… density and spine density are correlated in the ………………………….. of individuals with schizophrenia.

These reductions within …………………. boutons in layer ………… of the primary auditory cortex might contribute to ……………………………… and dysregulations in the ………………………… of postsynaptic pyramidal neurons.

A

synaptophysin punctum

auditory cortex

glutamate

3

functional glutamatergic deafferentation (synapse loss)

structural integrity

79
Q

Fill the gaps relating to schizophrenia. (7)

There is evidence for …………………. but not ………………….. changes in inhibitory neurons in the primary auditory cortex in schizophrenia.

Levels of ………………… protein are reduced by ~40% within inhibitory boutons in deep layer 3 of the auditory cortex in individuals with schizophrenia.

This is one of two enzymes that catalyze the conversion of ………………… to …………………. Therefore, decreased levels leads to reduced …………………… and …………………….. in the auditory cortex.

A

functional

structural

GAD65

glutamate

GABA

inhibitory tone

overexcitation

80
Q

Describe the molecular/cellular changes which occur in layer 3 of the auditory cortex in people with schizophrenia. (5)

A
  • Reduced GluR3 and GluR4 (AMPA subunits)
  • Reduced MAP2
  • Reduced synaptophysin
  • Reduced GAD65
  • Reduced spine density
81
Q

Describe how dopamine agonists and NMDA antagonists affect auditory verbal hallucinations during acute challenges. (1)

A

Produce only mild AVHs

82
Q

Describe how dopamine agonists and NMDA antagonists affect hallucinatory-like activity during chronic administration in monkeys. (1)

A

Both cause hallucinatory-like activity (eg. the animals may make threatening gestures at non-existent objects in space)

83
Q

True or false? Explain your answer if necessary. (1)

Adaptive changes induced during persistent hyper-NMDAR-hypo-dopaminergic states may be crucial for manifestations of hallucinations in schizophrenia.

A

False - it is the hypo-NMDAR-hyper-dopaminergic state which may induce hallucinations

84
Q

Describe how the activity of the superior temporal sulcus is altered in schizophrenia, when measured using fMRI. (1)

A

Hyperactivity

85
Q

Fill the gaps relating to schizophrenia. (3)

…………………… brain stimulation methods such as low-frequency transcranial magnetic stimulation (TMS) or cathodal transcranial direct current stimulation applied over the auditory cortex are reported to reduce the frequency and the severity of ………………………. in schizophrenia.

A recent meta-analysis reported a 2.9‑fold ………………………. response rate to active than to sham transcranial magnetic stimulation (TMS).

A

Inhibitory

auditory verbal hallucinations

higher

86
Q

Fill the gaps relating to schizophrenia. (7)

There are Theories of Abnormal …………………… that attempt to explain the positive symptoms of Schizophrenia.

According to these models, the primary cause of positive symptoms is an abnormal …………………….., otherwise known as a ……………………….

……………………………. may follow as a secondary consequence of attempts to understand the anomalous ……………………………….

For example, if patients can hear their own thoughts being spoken aloud, which is a …………………………….., it would seem logical to conclude that other people can also hear them, which is a ……………………………

A

perception

sensory experience

hallucination

delusions

sensory experience

hallucination

delusion

87
Q

According to theories of abnormal perception, what causes the positive symptoms of schizophrenia and how are they related? (2)

A

The primary cause is an abnormal sensory experience (a hallucination)

and delusions may follow as a secondary consequence of attempts to understand the anomalous sensory experience.

88
Q

Fill the gaps relating to schizophrenia. (9)

At the physiological level, neural networks involved in ……………………….., ………………………… and the processing of …………………………… (i.e. the generation of our prior beliefs about the world) and the neural networks required for ……………………………….. of the external world are highly interconnected.

Moreover, both prior beliefs and perception are dependent on the accuracy of our ………………………

This suggests that a single pathophysiological deficit could explain both ……………………….. and ……………………………

For example, a dysregulation in communication between the …………………………. and ………………………………. may explain complex phantom percepts, such as auditory hallucinations.

A

learning

memory formation

sensory information

higher cognitive perception

predictions

abnormal perceptions

abnormal beliefs

parahippocampal area

association cortices

89
Q

Fill the gaps relating to schizophrenia. (7)

Positive symptoms of schizophrenia may be caused by an abnormality in the brains’ …………………….. mechanisms,
such that new evidence (including sensory information) is not properly …………………., leading to false ………………………..

This failure may occur due to abnormal neuromodulation of the …………………….. of superficial pyramidal cells in cortical hierarchies (e.g. by …………………. and ……………………. interneurons).

A wide range of psychotic symptoms can be explained by a failure to accurately ………………….. sensory stimuli based on our generative models of the world.

A

inferencing

integrated

prediction errors

post-synaptic gain

GABAergic

dopaminergic

predict

90
Q

Describe a theory behind why schizophrenia emerges in late adolescence or early adulthood, based on Bayesian information processing. (1)

A

Bayesian inferential processes become more prominent as inhibitory neurotransmission (particularly in the prefrontal cortex) matures.

91
Q

Fill the gaps relating to schizophrenia. (10)

In Schizophrenia, subtle changes in …………………….. and ……………………….. may cause sensorimotor disturbances leading to stimuli feeling unusual.

Similarly, background sights and sounds that should be ……………………. in the present context may be ……………………

This leads to difficulties in allocating one’s ……………………. to the ……………………… aspects of the environment.

Persistent and noisy ……………………….. up the hierarchy could lead to the patient’s strange experiences.

The world will feel strange, and there may be a sense that there is an underlying cause that must be discovered. This is referred to as a ………………………….

Inferences are then required to account for these strange experiences, giving way to a compelling sense that a particular perception has a significant meaning for the patient (………………………….). When this inference is specific and related directly to the self it is referred to as a …………………………….., a common positive symptom.

A

motor function

sensory perception

irrelevant

enhanced

attention

most salient

prediction-error signals

delusional mood

a delusional perception

delusion of reference

92
Q

Describe a possible reason why people with schizophrenia may develop delusions. (1)

A

They need to develop a set of beliefs that must account for a great deal of strange and sometimes contradictory data (eg. hallucinations).

93
Q

Describe why people with schizophrenia often experience delusions of persecution. (1)

A

If one imagines trying to make some sense of a world that has become strange and inconsistent, and laced with sinister meaning and messages, the sensible conclusion might well be that one is being deliberately deceived.

94
Q

Give a possible consequence of persistent false prediction errors (uncanny coincidences) for people with psychosis/schizophrenia. (1)

A

They may abandon their well-established high-level models of the world.

95
Q

Fill the gaps relating to schizophrenia. (7)

In terms of the predictive coding framework, the problem that leads to the positive symptoms of Schizophrenia starts with ……………………………. being propagated upwards through the hierarchy.

This strongly signals that there has been a change, leading to a compelling demand for a new ………………… and a discounting of ………………………….

However, as the errors are ………………., these adjustments in the ………………… can never fully resolve the problem.

As a result, …………………………. will be propagated even further up the system to ever-higher levels of ………………………..

A

false prediction errors

inference

the existing model

false

model

prediction errors

abstraction

96
Q

It has been suggested that disruption to which neurotransmitter system accounts for changes in the salience of a stimulus in schizophrenia? (1)

A

Dopamine

97
Q

Fill the gaps relating to schizophrenia. (4)

A stimulus that evokes …………………. firing will grab attention and will demand an ……………………. or an ………………………….., and it is this that forms the germ of a ………………………….

A

dopamine

explanation

updating of belief

delusional belief

98
Q

It is hypothesised that neuronal firing mediated by which neurotransmitter encodes the precision (or uncertainty) of prediction errors? (1)

A

Dopamine

99
Q

What role might dopamine have on inference according to the predictive coding framework? (2)

A

Dopaminergic neurone firing may encode the precision (or uncertainty) of prediction errors

and this precision weights the influence of prediction errors on inference.

100
Q

True or false? Explain your answer if necessary. (1)

Serotonergic neurone firing is crucial for optimizing the balance between top-down prior beliefs and bottom-up sensory evidence.

A

False - it is dopamine

101
Q

Fill the gaps relating to inference in schizophrenia. (5)

The size of the prediction error is meaningless without an estimation of its ……………………
The salience of a sensory stimulus is not only coded by the …………………… of the prediction error, but also its …………………..
Therefore, altered ……………………. signalling could modulate the top-down predictions of the magnitude of sensory inputs, thus altering the precision of ………………………………

A

precision

magnitude

uncertainty

dopamine

bottom-up prediction errors

102
Q

Fill the gaps relating to schizophrenia (or really just normal Bayesian information processing). (13)

Normally, predictions are encoded at …………………… of a hierarchical system and are sent as …………………… signals to …………………. Whenever the incoming sensory data violate these predictions, a ………………………. signal is sent to update the …………………………….. at higher levels.

Formalized as Bayesian inference, predictions (also known as the ………………….) and sensory data (also known as the …………………….) are represented in the form of probability distributions. The posterior results from the combination of ……………… and ………………… according to Bayes’ rule, weighted by their respective …………………….., and updates the ……………………..
The new posterior mean is simply the old ………………….. added to a …………………….. prediction error.

A

higher levels

predictive

lower levels

prediction error

predictive model

prior

likelihood

prior

likelihood

precisions

predictive model

prior mean

precision-weighted

103
Q

Fill the gaps relating to schizophrenia. (7)

In psychosis, the balance between predictions and sensory data has been proposed to be disrupted, with a decreased precision in the …………………………. and increased precision of the ……………………… This imbalance biases Bayesian inference toward the ………………….. and away from the ……………….., resulting in the abnormally strong weighting of ……………………

Candidate mechanisms for decreased and increased precisions in the different factors are …………………………. receptors and …………………………. activity, respectively. Some psychotic phenomena may be explained by a compensatory increase in feedback signalling at higher levels of the hierarchy.

A

representation of priors

likelihood

likelihood

prior

the prediction error

hypofunction of glutamatergic NMDA

increased dopamine

104
Q

Fill the gaps relating to schizophrenia. (6)

One of the most striking features of Schizophrenia is ……………………. (false or distorted ……………………), such as people hearing other people talking about them or hearing their thoughts spoken aloud without an external sound source, i.e. without the person speaking to them really being present.

Theories of abnormal perception assume that the fundamental problem underlying positive symptoms is that the patient loses the ability to distinguish between ……………………………, i.e. that the patient persistently attends to stimuli that should be ………………………… and generates complex accounts of why these stimuli are …………………….

Failure to ignore irrelevant stimuli that result from one’s own thoughts and actions might be due to a failure to ……………………………….

A

hallucinations

perceptions

relevant and irrelevant stimuli

ignored

important

tag these stimuli as self-generated

105
Q

Fill the gaps relating to schizophrenia. (10)

Many of the positive symptoms associated with Schizophrenia involve misattribution of …………………. actions to ………………….
Therefore, certain positive symptoms may be caused by a defect in ……………………….

A significant difference between self-generated actions and something that occurs outside one’s control is that one can ………………………….. with self-generated actions.

If something is predictable it is easy to ……………….. and its sensory consequences can be ………………….., because they are …………………..

By contrast, a sensory experience that derives from an external stimulus is not ……………………. and hence not ……………………. or adapted to the outside world.

Unpredictable things are difficult to …………….., because it is crucial to experience them to update our understanding of the environment.

A

self-generated

others

self-monitoring

predict what will happen

ignore

dampened

unsurprising

predicted

suppressed

ignore

106
Q

Fill the gaps relating to schizophrenia. (9)

Normally, one can easily distinguish one’s own actions from those of others, even though every act performed has ……………………. that could just as easily have arisen from an ……………………..

At the physiological level this ability to discount one’s own actions requires a form of ……………………, i.e., the brain uses ……………………….. that generated the action to …………………. and ………………… the salience of the sensory consequences of the action.

Several experiments have found that patients with positive symptoms …………………….. responses to the sensory consequences of their own actions or their own speech.

If one’s experience of the sensory consequences of one’s action was not attenuated, then an active movement would feel like a ……………………….., i.e. it would feel as if the action was being driven by an ……………………..

A

sensory consequences

external cause

self-monitoring

motor commands

predict

reduce

fail to attenuate

passive movement

external force

107
Q

Describe how the brain ‘self-monitors’ to identify self-generated stimuli, and what are the results of this? (2)

A

The brain uses motor commands that generated the action

to predict and reduce the salience of the sensory consequences of the action.

108
Q

Fill the gaps relating to schizophrenia. (9)

Although a failure of self-monitoring can explain the features of passive experiences that characterize many positive symptoms, it does not seem very relevant to …………………..

For example, the sudden onset of a belief that ‘my neighbour is trying to poison me’ does not have an obvious link to …………………………..

For these positive symptoms, it seems more plausible that the underlying problem lies with the …………………………….., rather than with the perceptions from which the beliefs are derived.

Although logical reasoning does not seem to be markedly impaired in patients with Schizophrenia, there is evidence of problems with ………………………………..

This concept is associated with a ………………… approach to the study of belief formation.

Within this framework, a belief is the …………………….. that some proposition about the world is …………………….

This probability is continually updated by ……………………….. Abnormal belief formation occurs when beliefs are …………………………. on the basis of new evidence.

A

delusions

abnormal sensation

formation of beliefs

probabilistic reasoning

Bayesian

subjective probability

true

new evidence

not updated appropriately

109
Q

Fill the gaps relating to schizophrenia. (7)

Abnormalities in the integration of ………………………. into beliefs have been observed in …………………… patients.

Once a belief has become sufficiently strong, deluded patients show an abnormal …………………. against contradictory evidence.

In addition, patients with delusions ………………………… potential outcomes when making decisions.

These anomalies of ……………………… and …………………………. correspond to clinical observations of delusions.

Patients all too easily develop ………………………, which they then hold with great confidence and immunity to any counter evidence.

A

new evidence

deluded

bias

abnormally weight

probabilistic learning

decision making

false beliefs

110
Q

Describe how the updating of prior beliefs may be altered in schizophrenia and lead to delusions. (2)

A

People with schizophrenia may develop a ‘prior belief’, but then fail to update that belief based on the evidence that is presented to them.

They disregard evidence and do not update their beliefs.

Neuroscience Y3S1 (10 decks)

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