Docstoc

Classical Conditioning I

Document Sample
Classical Conditioning I Powered By Docstoc
					Pavlovian (Classical) Conditioning
     Example: “Bell” and Food
     First Few Trials          Later Trials

CS                        CS
US                        US

               UR                 CR UR

                   Time
 CS = bell                     CR = salivation
 US = food
 UR = salivation
Accidental (Not)
                Central Players
Unconditioned Stimulus (US)
     Initially “potent” – Initially elicits a response (inside or outside)

                           Positive Emotion (inside and hidden)
      Food US              Salivation (outside and observable)

Conditioned Stimulus (CS)
     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
           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 (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      key light CS  food US
               CR: peck key light CS

  Rats          insert lever CS  food US
                CR: lick lever
Not Reward (Instrumental) Learning

      • Long-box autoshaping
        • Omission training
 Form of the CR in Sign Tracking
 US = Water (note the closed beak)



 US = Food (note the open beak)




From Jenkins & Moore, 1973           video
              Conclusions
• 1. Conditioned behaviour is “evoked” by
  the CS, it is not “chosen” by the organism
• 2. The type of CS (keylight vs. lever) used
  can affect the behaviour observed
    2. What are the CS and US?

• An addict goes
  into severe
  withdrawal after
  seeing the dealer’s
  door
          Drug Conditioning Trial 1
Pre-Drug CSs          Drug US

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

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

Dealer, copping
corner, corner
syringes, needles,
cotton balls,                      Euphoria

lighters, rubber          heroin
tying-off cords
and stainless-steel
spoons
              Overdose and Death


New Context
                     heroin
      Opioids and Pain Tolerance
     Opioid
     administration           Opioid-induced hyperalgesia




Pain
tolerance

                      Opioid-induced
                      unconditioned
                       hypoalgesia
               Opiate Addiction
Administration               Withdrawal
• Hyperthermia               • Hypothermia
• Decreased Blood Pressure   • Increased Blood Pressure
• Skin Flushed and Warm      • Chilliness and Gooseflesh
• Meiosis                    • Mydriasis
• Drying of Secretions       • Lacrimination
• Respiratory Depression     • Yawning and Panting
• Antitussive                • Sneezing
• Relaxation                 • 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                               asymptote

• Non-linear


                      CR Strength
• Asymptote




                                    Conditioning Trials
Conditioning Occurs Over Trials
                   Extinction
                 Acquisition         Extinction
Strength of CR




                   CS&US               CS alone




                       Trials/Time
       Extinction of Tolerance

Group Extinction (M-P-M)
6 E-M           6 E-P
                                   Test E-M?
Group No Extinction (M-rest-M)
6 E-M          Rest in home Cage
Extingished
animals
(tolerance is
undone)


Rested animals
show a CR (more
tolerant)
                                                          Discrimination
                    1.2
                                      CS+
                                      CS-
                     1
Response Strength




                    0.8




                    0.6




                    0.4




                    0.2




                     0
                          1   2   3   4   5   6   7   8   9   10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

                                                                          Trials
Discrimination: Absence of pre-drug CSs
Heroin Overdose Death Rates
             Conclusions
• 3. Conditioned responses can be
  “compensatory”, bringing the organism
  back to homeostasis

				
DOCUMENT INFO