04 26 2012 Welcome to the Second Part of the Course Theoretical accounts of Pavlovian conditioning I What makes an effective CS and US What factors determine good conditioning A Contiguity the closer two stimuli are in space and time the stronger the association conditioned response 1 Delay conditioning is usually the strongest amount of conditioned responding 2 Slightly less conditioning is achieved with trace conditioning 3 Obviously very little evidence of conditioning with explicitly unpaired timing 4 Simultaneous presentations perfect contiguity and backwards presentations generally present very little or no conditioned responding a Contiguity cannot be the sole factor because perfect contiguity creates very little associations B Salience more intense or noticeable stimuli condition more rapidly 1 A larger outcome is valued more and attended to more by an individual 2 True for both the CS and the US a Examples i More food is valued more and will produce a conditioned response more quickly ii A louder tone is attended to more and will produce a conditioned response more quickly with fewer trials 3 More realistic CS conditions faster than less realistic CS a Experiment example quail mating i An L shaped terrycloth object with either no head or a stuffed female quail head is presented to a male and paired with the presentation of a real live female quail ii The terry cloth object with the stuffed head creates conditioning faster C CS US belongingness a US can condition some CSs better than others they just fit or belong together 1 Paradigm example rats are presented with a tube of sweet water each time the rat takes a drink a light flashes and a tone sounds a Sweet flavor is the CS b There are two USs which follow the drink and light tone i Either a foot shock or induced illness c Question can both fear cues and induced sickness be paired equally with flavors and audio visual cues NO i The rats that were conditioned with sickness as the US display an aversion to the sweet water very little reaction to the audio visual cues ii The rats which were conditioned with shocking display a fear response to the audio visual cues but no aversion to the sweet flavor of the water d Behavioral systems i Gut defense system triggered by gastric illness Evolutionarily advantageous ii Skin defense system triggered by cutaneous pain Sounds and sights are condition able to painful stimuli e Typical human fears i Snakes when a baby or small child observes an adult displaying a fear or aversion to snakes it picks up on that and is likely to acquire that fear itself f Cook and Mineka experiment i Monkey who is na ve to the CSs is presented with either a flower or a snake with a food dish behind it How long does it take the individual to reach over the object for the food ii Demonstrator monkey who is fearful of either snakes or flowers is displayed to the na ve monkey iii Same test as before Snake fear was more quickly conditioned hesitancy to reach over the snake than fear of the flower very similar measured response as the initial trial D Biological significance Biological strength a stimulus that commands a strong response can itself demand a response 1 Second order conditioning a Phase 1 CS1 light is paired with a US food salivate b Phase 2 CS1 light is paired with CS2 tone c Test After enough pairings the tone will elicit salivation 2 Sensory preconditioning a Phase 1 CS2 tone is paired with CS1 light no real response besides orientation b Phase 2 CS1 light is paired with US food salivation c Test tone will elicit salivation There is learning going on all the time through chains of associations of stimuli and responses How do we formally model accounts of Pavlovian conditioning II Two classes of model A Explain nature of CR 1 Stimulus substitution the CS becomes a substitute for the US the form of the CR is similar to the form of the UR a There is a CS pathway of neural activation as well as a US pathway which generates a response the two become connected such that the CS pathway comes to generate the response 2 Homeostasis special case of stimulus substitution not all conditioned responses mimic a primary UR a US elicits two URs opponent process theory i Primary UR moved system out of homeostasis ii Compensatory UR counteracts effects of primary UR returns the system to homeostasis b Form of the CR to the CS is like the compensatory UR NOT BOTH i Example fear conditioning and drug conditioning tolerance Fear o Primary UR movement increased heart rate o Compensatory UR freezing lower HR o CR freezing lower HR Drug conditioning o Primary UR lower HR lower BP analgesia o Compensatory UR increased HR increased BP sensitivity to pain o CR increased HR BP sensitivity to pain ii Evidence for opponent CR Drug users can overdose on a typical dose if taken in absence of drug associated cues opponent process is not cued so does not protect the individual Drug cues can elicit CR even in absence of the drug o Death can occur from under dose Opponent process for heroin use increased HR BP can cause heart attack if elicited in the absence of the process with counteracts or is typically counteracted III More on the behavioral systems theory Bill Timberlake A Proposed that conditioning B Feeding behavior system 1 Long delay CS engages more general search behavior a Will produce behaviors such as exploratory behavior 2 Short delay CS engages more focal search behaviors a Will produce behaviors such as goal tracking going to the food location grabbing the food 3 Example another rat presented as the CS