biological explanation for schizophrenia (Brain structure) Flashcards
name one biological explanation for schizophrenia
Brain structure.
what are the brain abnormalities?
Who concluded distinctions between positive and negative symptoms?
a substantial amount of research has suggested that the brain structure in people with schizophrenia is often different from this who don’t have schizophrenia
Crow 1985 concluded that maybe positive symptoms were better explained using neurotransmission and negative symptoms were more related to brain structure, hence why dopamine antagonist drugs are not effective.
what did crow 1985 conclude?
Crow 1985 concluded that maybe positive symptoms were better explained using neurotransmission and negative symptoms were more related to brain structure, hence why dopamine antagonist drugs are not effective.
enlarged ventricles
schizophrenics have smaller brains and enlarged ventricles (fluid filled cavities due to brain cell loss).
Suggests either brain tissue is being lost or certain brain areas have failed to develop fully.
what does the neurodevelopment hypothesis suggest?
schizophrenia is due to abnormal brain development’s which is latent in the individual and triggered by brain maturation during early adulthood.
loss of grey matter in the brain
what percentage of grey matter loss have neuroscientists detected?
what do patients with worse brain tissue loss also tend to have?
individuals with schizophrenia, including those who have never been treated, have a reduced volume of grey matter in the brain, especially in the temporal and frontal. neuroscientists have detected great matter loss up to 25%
patients with the worst brain tissue loss also tend to have the worst symptoms, which included hallucinations, delusions, bizarre and psychotic thoughts, hearing voices and depression.
links to individual parts of the brain
prefrontal cortex.
where is the prefrontal cortex?
what does it do?
what have schizophrenics shown when performing neuropsychological tasks?
The prefrontal cortex is at the very front and top of the brain, and it helps people think logically and organise their thoughts. Further brain imaging techniques indicate that schizophrenics show a characteristic low level of activity similar to those with frontal lobe damage.
and in contrast to control groups, patients have shown reduced metabolic rates in the prefrontal cortex when completing neuropsychological tasks, such as a card sorting task, that place demands on the prefrontal cortex.
This may be one reason they suffer from delusions and disorganised thought since the prefrontal cortex induces logical thinking and helps organise thoughts.
links to individual parts of the brain
visual and auditory cortices.
what do these ares of the brain do?
how are they different to schizophrenics?
These are ares of the brain that process vision and sound information from the eyes to the ears. In schizophrenics the brain acts the same way whether the patient is seeing and hearing something real or just hallucinating.
The hallucinations are as real to schizophrenics as reality.
links to individual parts of the brain
basal ganglia
where is the basal ganglia located?
what does it do?
how is this affected in schizophrenics?
located deep inside the brain and involves motor and thinking skills. she studies have shown that patients with schizophrenia have a larger basal ganglia. This might affect the movement patterns in schizophrenics, who often have motor dysfunctions.
Links to individual parts of the brain
Amygdala
what is the amygdala responsible for?
what is different in schizophrenics?
responsible for basic feelings, like fear, list and hunger. Patients with schizophrenia often have little emotion, and the amygdala is smaller in people with schizophrenia therefore won’t be bale to feel emotions very strongly.
What can cause the brain abnormalities
According to the neurodevelopment hypothesis, various factors during the womb, the birth process, or after birth can cause brain lesions and these can make the individuals affected vulnerable to schizophrenia.
Factors during foetal development in the womb
who examined the rates of schizophrenia amongst adults exposed to a virus during pregnancy?
what was the name of this virus?
What trimester had higher rates?
why is this?
what does this then mean for the diagnosis of schizophrenia?
-could be that a virus damages the brain during foetal development. in Helsinki in 1957 examined the rates of schizophrenia amongst adults who were likely to have been exposed to this epidermic of influenza virus during pregnancy.
those exposed during the second trimester had much higher rates than those exposed in other stages or not exposed at all.
cortical development is in a critical stage of growth during the second trimester.
-if the brain damage occurs pre-birth but schizophrenia doesn’t develop until so much later, this could mean the brain injury interacts with normal brain development.
What did researchers in Helsinki in 1957 examine?
Helsinki 1957 examined the rates of schizophrenia amongst adults who were likely to have been exposed to this epidermic of influenza virus during pregnancy.
having a difficult birth
Who reviewed studies of birth difficulties to support this?
what features of birth difficulty was associated?
Another cause of brain damage that has been linked to the later development of schizophrenia is having difficult birth.
Murray 1997 reviewed studies of birth difficulties and found that 7/8 studies found an association.
Low birth weight, premature birth, prolonged labour and oxygen starvation have all been found to be associated.
What did Murray 1997 review?
Murray 1997 reviewed studies of birth difficulties and found that 7/8 studies found an association.
Low birth weight, premature birth, prolonged labour and oxygen starvation have all been found to be associated
