Biological explanations Flashcards
one explanation of sz is genetics such as…
genetical genes that run in FAMILIES
Candidate genes
what is the evidence for sz running in families?
TWIN studies research found a HIGHER concordance rate in MMZ twins in comparison to DZ twins.
*aunt =2%
*sibling = 9%
* identical twin = 48%
Therefore the CLOSER the genetic relationship then the greater chance at developing sz.
what do candidate genes day?
Sz may be POLYGENIC and require a NUMBER of factors to work in COMBINATION.
Genes associated with increased risk include tohse coding the functioning of NEUROTRANSMITTERS including dopamine.
what is the original dopamine hypothesis?
HYPERDOPAMINERGIA i the SUB cortex focuses on HIGH levels of activity of dopamine in sub cortex. e.g. an excess of dopamine receptors in BROCAS AREA which is responsible for speech production may be associated with POVERTY or AUDITORY hallucinations.
what is the updated dopamine hypothesis?
HYPODOPAMINERGIA in the CORTEX. focuses on abnormal dopamine systems in the brain cortex. Low levels of dopamine in the prefrontal cortex responsible for THINKING.
Maybe BOTH hyper and hypo correct explanations, both high and low levels of dopamine in different brain regions are involved in sz.
what are neural correlates?
measurements of the STRUCTURE or FUNCTION of the brain that correlate with an EXPERIENCE in this case sz.
BOTH pos and neg symptoms have neural correlates
what are the neural correlates of negative symptoms?
Avolition is a neg symptom involving loss of motivation.
motivation involves anticipation of a REWARD and certain areas of the brain like VENTRAL STRAITUM ARE INVOLVED.
so ABNORMALITY to areas of the brain like the ventral stratum can cause avolition
what are the neural correlates of positive symptoms?
ALLEN scanned brains of patients with AUDITORY hallucinations and compared them with control group.
ppl with auditory hallucinations recorded LOWER activation levels in the superior temporal gyrus and anterior cingulate gyrus.
So REDUCED activity in these two areas is a NUERAL correlate of an auditory hallucination.
