Biological Explanations - Neural Correlates Flashcards
(17 cards)
What are neural correlates in schizophrenia?
Neural correlates are patterns of brain structures or activity differences which occur in conjunction with symptoms of psychological disorders and other experiences.
What is the importance of neural correlates in schizophrenia?
Psychologists are unsure about what exactly causes the symptoms of schizophrenia on a biological level, however research has identified that some neural correlates involved.
The best known neural correlate of schizophrenia is the neurotransmitter dopamine.
What is dopamine?
Dopamine is a neurotransmitter that is found in the limbic system of the brain, which is in a subcortical region.
It generally has an excitatory effect and is linked to pleasure.
What does the limbic system do?
The limbic system is involved emotional behaviour, motivation and memory.
How does dopamine affect symptoms of schizophrenia?
Some symptoms of schizophrenia are a result of either excess dopamine in the brain or of a super-sensitivity of the dopamine receptors.
What is the dopamine hypothesis in schizophrenia?
The original dopamine hypothesis was based on the discovery of Seeman that antipsychotic drugs which reduce the symptoms of schizophrenia caused symptoms similar to those with Parkinson’s disease, which is a condition associated with low dopamine levels.
Therefore, psychologists concluded that schizophrenia might be the result of high levels of dopamine.
What is hyperdopaminergia?
Hyperdopaminergia means that there are high levels of dopamine in the subcortical areas of the brain.
Increased dopamine receptors in pathways from the subcortex to Broca’s area may explain symptoms like poverty of speech and/or auditory hallucinations
What is the updated dopamine hypothesis in schizophrenia?
Davis et al proposed the addition of cortical hypodopaminergia. This means that abnormally low levels of dopamine in the brain’s cortex can explain symptoms of schizophrenia.
How do low levels of dopamine explain symptoms of schizophrenia?
Low dopamine in the prefrontal cortex, which is responsible for thinking, could explain cognitive problems such as negative symptoms like avolition.
It has been suggested that cortical hypodopaminergia leads to subcortical hyperdopaminergia, so both high and low levels of dopamine in different regions are part of the updated version.
How does the updated dopamine hypothesis explain the origins of abnormal dopamine function?
The updated version explains the link between dopamine and symptoms, as well as origins of abnormal dopamine function.
Recently, Howes et al states that both genetic variations and early experiences of stress, both psychological and physical, can make some people more sensitive to cortical hypodopaminergia and hence subcortical hyperdopaminergia.
What is an advantage of the involvement of neural correlates in schizophrenia?
P - research support for the theory that dopamine is involved in schizophrenia.
E - Curran et al > amphetamines increase dopamine and worsen symptoms in people with schizophrenia + induce symptoms in people without it.
E - antipsychotics also reduce dopamine activity and therefore reduce the intensity of symptoms according to Tauscher et al.
some candidate genes act on the production of dopamine or dopamine receptors.
L - suggests that dopamine is involved in the symptoms of schizophrenia and increases the reliability of the theory.
What is another strength of the involvement of neural correlated in schizophrenia?
P - research support for the dopamine hypothesis using animal studies.
E - amphetamines can reproduce symptoms of schizophrenia. In other research, such as that of Currran et al, amphetamines have been found to raise dopamine levels and in high doses can produce auditory hallucinations that resemble those in schizophrenia. Tenn et al induced schizophrenia-like symptoms in rats using amphetamines and then relieved its symptoms using drugs that reduce dopamine activity.
E - However, an issue with this research is that data from animal studies may not be as useful because humans and animals have different cognitive systems.
L - This supports the dopamine hypothesis as there is evidence of a link between amphetamines, dopamine and symptoms.
What is a counterpoint to the support for dopamine and amphetamines in the involvement of neural correlates in schizophrenia?
P - However, according to Depatie and Lal, other drugs that also increase dopamine levels, like apomorphine, do not produce schizophrenia like symptoms.
E - Garson has challenged the idea that the symptoms of amphetamine psychosis closely mimics schizophrenia.
E - Also, we should bear in mind that some of the evidence linking amphetamine psychosis to dopamine levels come from animal studies which may not be generalised to humans, so the link between amphetamine psychosis and schizophrenia may not be as close as some have suggested.
L - This means that amphetamine psychosis is not particularly strong evidence to support the dopamine hypothesis.
What is an limitation of the involvement of neural correlates in schizophrenia?
P - One limitation of the dopamine hypothesis is evidence for a central role of glutamate instead.
E - McCutcheon et al found that post-mortem and live scanning studies have consistently found raised levels of the neurotransmitter glutamate in several brain regions of people with schizophrenia.
E - In addition, several candidate genes for schizophrenia are believed to be involved in glutamate production or processing. This means that an equally strong case can be made for the role for other neurotransmitters.
L - This decreases the validity of the theory, suggesting that the dopamine hypothesis ignores other, more influential neurotransmitters.
ASK MADAM - NEURAL CORRELATES 2
ASK MADAM - NEURAL CORRELATES 2
ASK MADAM - NEURAL CORRELATES 2
