Pavlovian (Classical) Conditioning

Example: “Bell” and Food CS US URCR Later Trials CS US UR First Few Trials Time CS = bell US = food UR = salivation CR = salivation

Central Players Conditioned Stimulus (CS) Unconditioned Stimulus (US) Initially “potent” – Initially elicits a response (inside or outside) Initially “neutral” – Does not initially trigger same response as does the US Lights, sounds, tastes, odors, etc. After pairings with the US, elicits a conditioned response Food US Positive Emotion (inside and hidden) Salivation (outside and observable)

Early Experiments Stefan Wolfsohn: –Dog learns to salivate at the sight of sand before it is placed in the dog’s mouth Anton Snarsky: –Dog learns to salivate at the sight of black liquid (acid) before it is placed in the dog’s mouth (Pavlov’s interpretation: “higher thinking!”)

1.What are the CS and US? A pigeon pecks a light that signals the presentation of food

Autoshaping (Sign Tracking) When a localized CS and a “pleasurable” US are paired, a CR is sometimes directed at the CS. Pigeons CR: peck key light CS Rats key light CS  food US insert lever CS  food US CR: lick lever

Not Reward (Instrumental) Learning Long-box autoshaping Omission training

Form of the CR in Sign Tracking From Jenkins & Moore, 1973 US = Water (note the closed beak) US = Food (note the open beak) video

Conclusions 1. Conditioned behaviour is “evoked” by the CS, it is not “chosen” by the organism 2. The situation, species, and procedures used can affect whether animals approach the CS or the US in appetitive conditioning.

2. What are the CS and US? An addict goes into severe withdrawal after seeing the dealer’s door

Drug Conditioning Trial 1 Euphoria Dealer, copping corner, corner syringes, needles, cotton balls, lighters, rubber tying-off cords and stainless-steel spoons Pre-Drug CSsDrug US heroin

Trial 2 heroin Euphoria Pre-Drug CSs Dealer, copping corner, corner syringes, needles, cotton balls, lighters, rubber tying-off cords and stainless-steel spoons Pre-Drug CSsDrug US

Trial 10 heroin Euphoria Dealer, copping corner, corner syringes, needles, cotton balls, lighters, rubber tying-off cords and stainless-steel spoons Pre-Drug CSsDrug US

Overdose and Death heroin New Context

Pain tolerance Opioid-induced unconditioned hypoalgesia Opioid-induced hyperalgesia Opioid administration Opioids and Pain Tolerance

Opiate Addiction Administration Hyperthermia Decreased Blood Pressure Skin Flushed and Warm Meiosis Drying of Secretions Respiratory Depression Antitussive Relaxation Withdrawal Hypothermia Increased Blood Pressure Chilliness and Gooseflesh Mydriasis Lacrimination Yawning and Panting Sneezing Restlessness

Some Controlled Experiments Mor-ROOM/Sal-CAGE –Morphine in a distinctive room –Saline in the home cage Mor-CAGE/Sal-ROOM –morphine in the home cage –saline in a distinctive room Saline –saline in both environments

Test: No morphine in the distinctive room

Conditioning Trials Acquisition curve Non-linear Asymptote Conditioning Trials CR Strength asymptote

Conditioning Occurs Over Trials

Extinction Trials/Time Strength of CR AcquisitionExtinction CS&USCS alone

Extinction of Tolerance Group Extinction (M-P-M) 6 E-M6 E-P Test E-M? Group No Extinction (M-rest-M) 6 E-MRest in home Cage

Rested animals show a CR (more tolerant) Extingished animals (tolerance is undone)

Discrimination: Absence of pre-drug CSs

Heroin Overdose Death Rates

Conclusions 3. Conditioned responses can be “compensatory”, bringing the organism back to homeostasis