5.1.3 Sz- Bio exp (Brain S) Flashcards
Why do we look at brain structure as a factor in development of schizophrenia?
Because there has been much evidence to suggest that brain structure is different in schizophrenia patients compared to a healthy person.
What did Crow (1985) conclude about brain structure and symptoms of schizophrenia?
That positive symptoms are best explained by neurotransmitters and negative symptoms are best explained by brain structure.
List the 3 elements of brain structure as a biological explanation for schizophrenia.
1) Enlarged ventricles
2) Damaged frontal lobes
3) Loss of grey matter
Define ‘ventricles’.
Centres of the brain that contain spinal fluid and supply blood and oxygen to densely packed neurons.
How do ventricles explain the cause of schizophrenia?
They have smaller brains and larger ventricles which causes a thinning of the cerebral lining. Enlarged ventricles is usually due to underdevelopment in some areas or loss of brain cells that causes fluid to fill the empty space. Suggests that either brain tissue is being lost or certain areas havent fully developed eg frontal lobes, temporal lobes.
State a statistic about schizophrenic patients and enlarged ventricles.
Approximately 15% of patients with schizophrenia have enlarged ventricles. Research from CAT scans
Which areas of the brain are said to be a potential factor in causing schizophrenia?
Frontal lobes
How does damage to the frontal lobes explain the cause of schizophrenia?
Catatonia and speech arrest are common negative symptoms for schizophrenic patients and those that suffer from brain damage. Brain imaging techniques have shown that low level of activity in the frontal lobe is similar to those with frontal lobe damage when performing a card sorting task.
Why does the onset of schizophrenia seem to be most common in adolescence?
The prefrontal cortex develops through adolescence and so if it is damaged prior, the effects would only become known during young adulthood whereby schizophrenia is most commonly diagnosed.
What is grey matter in the brain?
Darker tissue that consists of nerve cells and dendrites.
Helps diff areas of brain communicate
How does loss of grey matter explain the cause of schizophrenia?
Patients who have never been treated for their schizophrenia show a reduced volume of grey matter, especially in the frontal lobe. Damage starts in the outer regions of the brain and spreads to the rest over a 5 year period and those with the worst tissue loss show the worst symptoms.
State a statistic about schizophrenic patients and loss of grey matter.
There is a grey matter loss of up to 25% in patients with schizophrenia
What factor is said to cause this brain damage?
(clue- birth)
Exposure to viruses/brain damage as a fetus.
What did Cantor-Graae et al (1994) find in terms of difficulties during birth and schizophrenia?
He found that difficulties during birth is more likely to result in schizophrenia in those who do no have a family history of the disease.
Give an example of a virus that has been seen to lead to schizophrenia if exposed to it in the womb.
People who were exposed to the influenza virus during the second trimester of their fetal development were more likely to develop schizophrenia.
What did Murray (1997) find in terms of difficulties during birth and schizophrenia?
Reviewed birth difficulty studies, found 7/8 to be relevant to brain damage- can lead to Sz. Low birth weight, premature birth, prolonged labour and oxygen starvation.
(Link- brain damage occuring pre birth may manifest into Sz in late teens/ early 20s bc thats when PFC fully develops - BEFOREHAND THE BRAIN INJURY INTERACTS WITH NORMAL BRAIN DEVELOPMENT OUTSIDE OF CORTICAL DEVELOPMENT-and symptoms of Sz show)
How could damage to the prefrontal cortex in the womb link to onset of schizophrenia?
Bbrain damage occuring pre birth may manifest into Sz in late teens/ early 20s bc thats when PFC fully develops. The PFC is responsible for decision making, impulsivity, emotional regulation, and personality.BEFOREHAND THE BRAIN INJURY INTERACTS WITH NORMAL BRAIN DEVELOPMENT OUTSIDE OF CORTICAL DEVELOPMENT-and then symptoms of Sz may show
How might dopamine activity also link to onset of schizophrenia?
Dopamine activity peaks in adolescence so may set the stage for the onset of symptoms.
EACH-Evidence
1.P- Goldstein et al (1999) supports
E- Found greatest reduction in SZ brain matter to be paralimbic cortex, Compared SZ to non sz controls, matched pairs (age, sex, ethnicity), several areas of cortex in Sz patients smaller than controls.
E- S, suggests that loss in the cortical region can lead to the development of Sz symptoms, supports brain structure s an explanation of the development for Sz
2.P-
E-
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