3.2.2 Dopamine Explanation (Sch) Flashcards
(Dopamine) what did research in the 1950s look at the role of dopamine in?
Parkinson’s disease
(Dopamine) what is Parkinson’s disease?
Neurological disease causing tremors and slow imprecise movement
(Dopamine) what did the drug L-DOPA do for the symptoms of Parkinson’s?
Increased the amount of dopamine reducing Parkinson’s symptoms
(Dopamine) when people were given L-DOPA what did they show? What did this lead to?
Behaviours similar to those of individuals with schizophrenia
Link made between dopamine and schizophrenia
(Initial hypothesis) what did the initial dopamine hypothesis propose?
Individuals with schizophrenia had too much dopamine
(Initial hypothesis) as individuals had too much dopamine they demonstrated symptoms related to what?
High levels of dopamine
(Initial hypothesis) The initial hypothesis was supported by what?
Research
(Initial hypothesis) What did Griffith et at do to non schizophrenic patients?
Induced psychosis
(Initial hypothesis) Griffith Dave volunteers what drug and what did it do?
Dextro-amphetamine
Drug increasing amount of dopamine in the brain
(Initial hypothesis) Griffith - what symptoms did the volunteers demonstrate?
Paranoid delusions
Detached emotional response
(Initial hypothesis) the initial hypothesis was identified as being too what?
Simple
(Initial hypothesis) simple - administering drugs to reduce dopamine had little to no effect on who?
People suffering with negative symptoms of schizophrenia
(Dopamine receptors) the situation was complicated by the discovery of what?
Several subtypes of dopamine receptor sites D1-D5
(Dopamine receptors) where were these new found receptors distributed?
Widely in the cerebral cortex and subcortically in the limbic system
(Dopamine receptors) which receptor was focused on and why?
D2
This specific receptor was blocked by antipsychotics
(Dopamine receptors) why did the limbic system become the main focus of the dopamine hypothesis?
That is where D2 receptors are found
(Revised hypothesis) what has been the main focus of study in recent years?
The role of dopamine in the limbic system
(Revised hypothesis) what does the limbic system consist of?
Subcritical structures involved in emotion and memory formation
(Revised hypothesis) what leave from the limbic system?
Nerve pathways to many other subcortical and cortical regions
(Revised hypothesis) what are the two main pathways associated with schizophrenia?
Mesolimbic pathway
Mesocortical pathway
(Revised hypothesis) what does the mesocortical pathway consist of?
Ventral tegmental area
Nucleus accumbens
(Revised hypothesis) mesolimbic - where does too much dopamine come from?
Neurons firing too often or too quickly
(Revised hypothesis) mesolimbic - too much dopamine results in what?
Overstimulation and the positive symptoms e.g. Hallucinations
(Revised hypothesis) mesolimbic - antipsychotic drugs reduce what?
Dopaminergic transmission
Dopamine activity in the pathway
Positive symptoms
(Revised hypothesis) mesocortical - this pathway carries signals from where to where?
Ventral tegmental area to frontal lobe
(Revised hypothesis) mesocortical - what is this nerve pathway essential in?
Emotional response
Motivation
Cognition
(Revised hypothesis) mesocortical - what is hypofunction?
Too little dopamine
(Revised hypothesis) mesocortical - where is hypofunction evident?
D1 receptors of frontal lobe of individuals with negative symptoms
