Cues without consequences- Latent Inhibition and Schizophrenia Flashcards
What is Schizophrenia and how is it treated?
It is a serious mental disorder causing hallucinations and delusions. It is treated with DA antagonist drugs.
Why is it believed that Dopamine is implicated in schizophrenia?
Because DA agonists induce schizophrenic like symptoms.
Why are researchers aiming to make new drugs to treat schizophrenia?
The prognosis is poor (20-30% don’t respond) even though the incidence is low.
What is an example of an indirect DA agonist?
amphetamines.
Griffith et al did a study where ppts were given amphetamines over 10 days and they developed psychotic symptoms after 2-5 days.
What is an example of a DA antagonist used to treat schizophrenic symptoms?
Haloperidol
Latent inhibition is impaired in people with schizophrenia.
Define latent inhibition.
LI is a term used in classical conditioning to describe when you have been pre-exposed to a stimulus it reduces later learning; it is more difficult to acquire a new meaning.
Define conditioned inhibitor.
A CS that prevents the response of the CR is called a conditioned inhibitor.
Baruch et al., 1988 found that latent inhibition deficits in ppts with Schizophrenia, using what…?
The counter increment variant.
LI is reduced or abolished in…. schizophrenia but not…?
acute but not chronic. Meaning that in acute schizophrenia learning is improved.
What is the translational evidence for latent inhibition being implicated in schizophrenia?
Gray et al, 1996- amphetamine treatment abolishes LI in normal human ppts.
Williams et al, 1997- haloperidol can reduce LI in humans
Kumari et al 1999 found that haloperidol effects depend on…
psychoticism.
High in P- LI shown when given amphetamines but increased learning when given haloperidol.
Low in P- increased LI and reduced learning when given haloperidol.
Which area of the brain implicated latent inhibition if damaged?
Nucleus Accumbens
Latent inhibition is reduced by…
excitotoxic lesions to shell nucleus accumbens
