Learning about the world Flashcards
What functions does dopamine control?
Reward, motor and release of hormones
Where do the projections of dopamine go to and where do they start?
They begin in the midbrain in the Substation Nigra VTA
projecting to the
Striatum,
Nucleus accubens and Dorsal PFC
What lines of evidence suggest that dopamine is related to Schizophrenia?
Amphetamine and cocaine worsen Schizophrenia and can induce it
+D2 receptors
L-dopa was taken up quicker
MS dopamine system disruption related to the severity
Dop antagonism improves symptoms
How can dopamine explain the positive and negative symptoms in each pathway?
MC low Dop = Neg and Cog
ML High Dop=
Positive symptoms
Tuberoinfundibular Prolactine secretion
NS Movement
How do we use dopamine to learn?
Dop levels increase when reward is first given, nicer reward, bigger release.
Learning causes Dop release is prediction and not after reward.
If no reward, drop in Dop
This is mech in learning- dop firing adjusts to internalise cause and effect
How does Millers Hypothesis explain schizophrenia?
Dysregulation of Dopamine results in meaning being attributed where there is none.-Bio
Explanational narrative needed to explain this-Cog
Aberrant Salience causes distress
Antipsychotics stops salience, but stops motivation salience too.
What is reinforcement-related speeding?
When the response time is quicker due to the anticipation of a reward.
What did Murray et al show with regard to reward and schizophrenia?
That patients were unable to change reaction to salience in reward task and and had similar times regardless of reward.
What was the main results difference between Murray’s and Corlett’s study?
The area of the brain implicated: Mid brain vs PFC.
How do avolition and anhedonia relate to negative symptoms?
Schizophrenics have flattened affect.
If they cannot enjoy something they are unlikely to cause it.
However, many studies suggest they can feel pleasure. It is their pleasure anticipation that may be an issue
Mixed results with imaging
What area of the brain is inversely correlated with the severity of negative symptoms?
Ventral striatum,
Suggesting the anticipation of reward is jeopardised. Atypical antipsychotics may normalise this.
What are the steps in goal directed behaviour and where in the brain is the process thought to live?
Value computation: How valuable is the action and what is the cost of attainment?
Orbital FC
DLPFC
ACC
What are some of the lines of evidence that show schizophrenics struggle with reward value computation?
Winsconsin card sorting -unable to update meaning
Some studies: Unable to reverse learn, rules
Gold study: Less likely to choose easy, sure money task.
