Lecture 12 - Cues Without Consequences

Question 1

Outline background of Schiz

Answer 1

Mental disorder: hallucinations and delusions
DA agonists
Treated DA antagonists

Question 2

Outline drugs needed treat Schiz

Answer 2

24 million cases 
2-10 per 1000 
Equal to or less than 25% recover 
20-30% do not respond at all existing drugs 
Ineffective negative symptoms 
Suicide risk 10%. 25% attempt

Question 3

Outline Frith 1979 cognitive and attentional problems in Schiz

Answer 3

Basic cognitive defect is an awareness of automatic processes which are normally carried out below level of consciousness

Question 4

Outline Maher 1983 cognitive and attentional problems in Schiz

Answer 4

Failure of attentional focusing to respond to stimulus redundancy

Question 5

Outline Hemsley 1987 cognitive and attentional problems in Schiz

Answer 5

Less able make use of redundancy and patterning of sensory input

Question 6

Outline Cutting 1985 cognitive and attentional problems in Schiz

Answer 6

Concentrate on detail at expense of them

Question 7

What is the common theme of cognitive and attentional problems in Schiz

Answer 7

Issue with attention
Normally we tune our background noise, things not relevant
Schiz do not tune out background noise

Question 8

Outline Griffith et al 1972 - Amphetamine Psychosis

Answer 8

7 ppt users not prior history psychosis
10mg dextroamphetamine every house up to 5 days
All became psychotic 2-5 days
Delusions auditory = poisoning experimenters and electric dynamo thought control, receive special messages just for them
E.g. TV/Facebook specific relevance and specific message to them

Question 9

Outline Pro and Anti-Psychotic Drug Actions

Answer 9

Amphetamine is psychotomimetic and indirect DA agonist
Stimulates dopamine
Typical antipsychotics are DAD2 antagonists e.g. haloperidol
Block D4 and 5-HT2
D1 agonists boost DA hype-function in frontal cortex

Question 10

Is Latent Inhibition impaired in Schiz?

Answer 10

Yes 
Impaired by amphetamine model 
Extends studies individual differences 
If on medication may return to normal 
Rat model identify neural substrates 
Effects LI weaken associative learning

Question 11

Outline latent Inhibition

Answer 11

Csa—> Nothing
CSa —> US
Pre exposure stage 1 reduced later learning stage 2
Pre exposure set up as a cue with no consequence

Question 12

Outline the basic experimental design for latent inhibition

Answer 12

Comparing learning Pre-exposure and control groups. Follow up test associative learning (and drug free)

Measured 2x2 design

Assess pre exposure and control each experimental condition

Comparing non ore exposed group determine effects on conditioning

Question 13

Outline how Latimer Inhibition is abolished in rats under amphetamine

Answer 13

Amphetamine increase shock sensitivity as it is a stimulant
Meta analysis: effect most from over conditioning in ore exposed group. No suppression non-pre-exposed group

BUT presence amphetamine there is suppression non-pre-exposed

Question 14

How do you test for latent Inhibition in humans

Answer 14

Lubows Lab

Task not too obvious
US = counter increment
Task: work which series nonsense syllables predicts counter increment

Masking task
CS = white noise (pre exposed and later predicted)

Question 15

Outline Latent Inhibition deficits in ppts with Schiz

Answer 15

Link loss LI and Schiz shown counter increment variant

LI impaired, abolished acute Schiz

LI relative learning increase can’t be due to non specific features of disease process

Question 16

Outline translational evidence of latent Inhibition and Schiz

Answer 16

Amphetamine treatment abolishes LI in normal ppts 5mg

Haloperidol reduce LI humans

Any beneficial effect expected depend baseline DA activity

Haloperidol effects health humans depend on psychoticism scores - single 5mg

Question 17

Outline Haloperidol effects depending on Psychoticism - Kumasi et al 1999

Answer 17

High and low psychoticism reduction LI

Low psychoticism reduces haloperidol

Question 18

Define measuring schizotypy in normal ppts O-Life

Answer 18

Are sounds you hear in your daydream really clear and distinct?

Do you believe in telepathy?

Are your thoughts sometimes so strong that you can almost hear them?

Do you think you could learn to read others minds if you wanted to?

Question 19

Outline Shrira and Kaplan 2009 experiment on Latent Inhibition reduces with Schizotypy

Answer 19

2 procedures:
1 without masking. 1 with masking.

Schizotypy relates LI in circumstances

Question 20

Translating back research on Latent Inhibition to animal models

Answer 20

Loss of selectivity which normal attention ordinarily exercises among sensory impressions

Core deficit suggests use attentional measures

Rat model tells us which NT systems and brain structures are important

Question 21

Define low latent Inhibition

Answer 21

Openness environmental stimuli irrespective past significance

Question 22

Latent Inhibition in rats modulated by amphetamine and haloperidol

Answer 22

Haloperidol alone = enhancement

Together = restoration

Question 23

Outline brain circuitry of interests by Cassaday and Moran 2010

Answer 23

Latent Inhibition reduced by excitotoxic lesions to shell region of nucleus accumbens

Damage selective regions of nucleus accumbens reduce/lower LI

Question 24

Outline other selective learning tasks by Cassaday and Moran 2010

Answer 24

Salience modulation: overshadowing (intrinsic), LIT, blocking (acquired)

Failure of attentional focusing respond to stimulus redundancy

Schiz sleds able make use redundancy and patterning sensory input

Question 25

Theoretical framework Cassaday and Moran 2010

Answer 25

D1 agonists based known therapeutic effect

Or

D1 antagonists based on direction effects in overshadowing?