brain structure as a cause of SZ Flashcards
What are ventricles
ventricles are areas in the brain that supply nutrients and remove waste. they are filled with cerebrospinal fluid and they help give the brain buoyancy and cushioning.
what causes enlarged ventricles
this is caused by death of brain tissue surrounding the ventricles. this is caused during the birthing process if the baby had a low birth weight, if they experienced a prolonged labor and oxygen starvation. it can also be due to brain lesions (brain damage) due to an accident or a stroke. it will impact the growth of the brain. it can also be related to viruses
give research to support enlarged ventricles
suddath et al used MRI scans on MZ twins in which one was a SZ and found that the one with SZ generally had enlarged ventricles and a reduced anterior hypothalamus. in 12 out of 15 pairs the SZ could easily be identified from brain image.
this has high internal validity. uses scientific methods such as MRI scans which are objective. they can be replicated to test the consistency of the researchers results.
However they still have to be interpreted so they may be influenced y subjective opinions.
what proportion of the brain is reduced in SZ
25% reduction in brain tissue in SZ
what structures of the brain are said to have abnormal structures in patients with SZ and explain how this may be the case.
PFC (Related to decision making and problem solving, reduced functioning could lead to social withdraw and negative symptoms of SZ because the individual feels overwhelmed by anxiety), temporal lobe (auditory information ie overactivity/sensitivity could lead to positive symptoms such as hallucination and delusions -psychosis), hypothalamus, hippocampus (reduced brain functioning in the hippocampus can lead to poor conditioning as STM cannot be converted to LTM so don’t know how to behave in society ie word salad) basal ganglia (linked to dopamine pathway and cognitive disfunction as well as motor functioning under activity can lead to negative symptoms such as absence of the blinking reflex, speech arrest and poor visual focus).
why might SZ develop during adolescence
give research to support
the PFC matures late, typically in adolescence, so injury in this area of the brain would not be apparent until then.
could also be due to younger people being more likely to participate in dangerous activity leading to damage to the brain through an ABI.
caster subjected monkeys to brain imaging X rays during foetal development and found they showed no ill effects during childhood but during puberty they started to develop positive symptoms of SZ.
however lacks generalisability as it was used on animals. they have different brain structure and development stages so we cannot establish that this would be the same in humans. however its unethical to replicate on humans.
what does Crow suggest
brain injuries were typically more related to negative symptoms of SZ. which is supported by the fact that dopamine antagonists are not effective.
how does Fusae poli criticise this explanation of SZ
He found that patients who had been given AP treatment showed an overall reduction in brain volume and grey matter.
the treatment could be causing the reduced brain matter therefore it is not a cause of sz as the symptoms were present beforehand.
Swayze reviewed __ studies and found …
50
abnormally large ventricles in the brains of patients with sz
