1. Chapter 7 Classical Conditioning: Learning to Predict Important Events

2. 7.1 Behavioral Processes

3. 3 Basic Concepts of Classical Conditioning Error Correction and the Modulation of US Processing From Conditioning to Category Learning Modulation of CS Processing Further Facets of Conditioning

4. 4 Basic Concepts of Classical Conditioning Unconditioned stimulus (US)—stimulus naturally evokes some response, the unconditioned response (UR). Conditioned stimulus (CS)—a cue that is paired with a US and eventually elicits the anticipatory response, the conditioned response (CR).

5. 5 Basic Pavlov’s Experiment and Terminology

6. 6 http://www.youtube.com/watch?v=w3sgR12ZSh8

7. 7 Varieties of Conditioning Aversive conditioning—when the US is unpleasant Electric shock (fly conditioning) Airpuff to the eye (eyeblink conditioning) Appetitive conditioning—when the US is pleasant Food (dog salivation conditioning) Sex (quail conditioning)

8. 8 Widely Used Classical Conditioning Preparations

9. 9 Odor Conditioning in Flies Adapted from Dudai et al., 1976

10. 10 Sexual Conditioning in Quail Adapted from Domjan et al., 1986.

11. 11 Eyeblink Conditioning Richard F. Thompson Mark Gluck

12. 12 (a) courtesy of R. F. Thompson; (b) from Allen, Chelius, & Gluck, 2002; (c) from Allen et al., 2002. Acquisition of Eyeblink Conditioning: Learning a New Association

13. 13 Extinguishing an Old Association Extinction—when CS is presented without US, no longer predicts the CR. CR decreases and eventually disappears. Increasing CS–US trials slows extinction. Continuous reinforcement speeds learning, but also extinction. Question: Does the learner forget the CS–US association?

14. 14 Acquisition and Extinction of Eyeblink Conditioning Adapted from data in Moore & Gormezano, 1961.

15. 15 Extinguishing an Old Association Answer: No Reconditioning occurs more rapidly. Spontaneous recovery may occur. Learned association reappears after a period of extinction. The CR may reoccur in a new environment!

16. 16 Conditioned Compensatory Responses Expectation can elicit a preparatory (or compensatory) response. Tolerance—decreased reaction to a drug; larger doses are required to achieve the same effect. Homeostasis—body’s tendency to gravitate toward equilibrium.

17. 17 The Rescorla-Wagner Model and Error-Correction Learning Model predicts CR strength, trial-to-trial. CR strength increases, but less and less on each trial (negative acceleration). Based on a prediction error—the difference between subject’s expectation of US (e.g., airpuff) and whether the US actually occurs.

18. 18 Influence of the Rescorla– Wagner Model Explained previously puzzling results. Allowed researchers to make predictions that couldn’t be made previously. Cannot account for every kind of learning. A useful starting point.

19. 19 Associative Bias and Ecological Constraints Conditioned taste aversion—one-trial learning that a novel taste is a powerful cue for illness. Rats developed bait shyness/taste aversion to food (CS) with US of illness (poison). Garcia-Koelling taste-aversion study: Avoidance with tone (CS) + shock (US)

20. 20 7.1 Interim Summary Classical conditioning = learning the predictive nature of stimuli (cues predict desirable or undesirable events). If unconditioned stimulus (US) is repeatedly and reliably preceded by neutral stimulus, (e.g., a bell), neutral stimulus can become conditioned stimulus (CS). CS evokes a conditioned response (CR). CRs are anticipatory responses that prepare an animal for the expected US.

21. 21 7.1 Interim Summary Eyeblink conditioning: Similar across species. Results in one species can apply to others. Compensatory CRs occur in body systems programmed for homeostasis. Tendency of various body functions (e.g., heart rate) to remain at a relatively constant level.

22. 22 7.1 Interim Summary Pairing of CS with a US is not sufficient for conditioning to occur. For CS to become associated with US, it must provide valuable new predictive information. Even if cue is predictive of US, it may not become associated with US if its usefulness has been “blocked” by a co-occurring cue with a longer history of predicting the US.

23. 23 7.1 Interim Summary Rescorla and Wagner (1972): Learning should occur in proportion to the degree to which US is unexpected the first time it is experienced. Key assumption in Rescorla–Wagner model: With multiple CS cues present, the expectation (or prediction) of US is calculated as the sum of the weights of all of the cues present on that trial.

24. 24 7.1 Interim Summary Rescorla–Wagner model combines explanatory power with mathematical simplicity. Takes an idea (classical conditioning is driven by a prediction error); pares away everything but the essential details; explores nonobvious implications. Model is a starting point from which many subsequent models have been built.

25. 25 7.1 Interim Summary Extinction = more than just the loss of learned association. Involves learning an opposing “don’t respond” command; competes with (and masks) original CS–US association.

26. 26 7.1 Interim Summary Human learning is analogous to more elementary learning processes studied in animal conditioning experiments. Some complex human abilities (e.g., speech recognition, motor control, category learning) can be understood as emerging from associative learning processes similar to those studied in conditioning paradigms.

27. 7.2 Brain Substrates

28. 28 7.2 Brain Substrates Mammalian Conditioning of Motor Reflexes Unsolved Mysteries—Riding the Brain’s Waves into Memory Invertebrates and the Cellular Basis of Learning

29. 29 Mammalian Conditioning of Motor Reflexes CS–US association my be stored in: Purkinje cells of the cerebellar cortex. Cerebellar interpositus nucleus (eyeblink CR pathway).

30. 30 Electrophysiological Recording in the Cerebellum In many well-trained animals, the Purkinje cells switch off in response to the CS. The cerebellum (interpositus) may be responsible for eyeblink conditioned responses (CRs) and NOT (unconditioned responses) URs.

31. 31 Conditioning Is Impaired when the Cerebellum is Damaged The CR’s output pathway is interpositus nucleus of cerebellum. Even small interpositus lesions destroy and prevent CRs. Lesions in cerebellar cortex (including Purkinje cells) affect timing of CR learning. Seen in autistic children.

32. 32 The Hippocampus in CS Modulation Basic classical conditioning may not involve the medial temporal lobe (MTL). However, removal of the hippocampus eliminates latent inhibition in a rabbit’s eyeblink conditioning. Question 1: Hippocampus involved in controlling CS salience in classical conditioning? Question 2: Does the rabbit forget the CS pre- exposure, as amnesiacs might?

33. 33 Unsolved Mysteries—Riding the Brain’s Waves into Memory Hippocampal theta waves, present during learning and REM sleep; may facilitate memory storage. Rabbits whose eyeblink conditioning trials were triggered by theta activity learned much faster than a control group. Increased theta activity during learning in patients with epilepsy.

34. 34 7.2 Interim Summary Two sites in cerebellum where CS and US information converge (potential locations for storage of the CS–US association). Purkinje cells in the cerebellar cortex Interpositus nucleus The only output pathway from the cerebellum; the route through which the learned response travels to behavior- controlling motor systems (e.g., eyeblink CR). Interpositus nucleus is involved in formation and execution of CR; cerebellar cortex is involved in mediating response timing.

35. 7.3 Clinical Perspectives

36. 36 7.3 Clinical Perspectives Drug Addiction and Abuse: Linked to Classical Conditioning Learning and Memory in Everyday Life— Kicking the Habit

37. 37 Drug Addiction and Abuse: Linked to Classical Conditioning Drug tolerance increases with use in the same drug-taking context (situation- specific). Even subtle changes (e.g., to drug taste) can overrun tolerance and increase drug effects. Increases possibility overdose.

38. 38 Study of Drug Tolerance From Siegel et al., 1982.

39. 39 In first-time dose rats, large heroin dose led to: 96 percent fatal overdose. In rats with small heroin dose before larger dose in a different location: 64 percent fatally overdose. In rats with small dose before larger dose in the same location: Only 32 percent overdose. Drug Addiction and Abuse: Linked to Classical Conditioning

40. 40 Drug Addiction and Abuse: Linked to Classical Conditioning Environmental CSs (e.g., appearance and smell of drug-taking location) produce CR drug craving in anticipation of US drug. Relapse can occur from exposure to such powerful CSs. Try to avoid as many cues as possible. Need help from non-drug using friends and family to avoid powerful CSs.

41. 41 Learning and Memory in Everyday Life—Kicking the Habit Drug using environmental CSs may elicit intense cravings in recovering addicts. Increases relapse vulnerability. Bouton (2000) suggests that therapists conduct cue-exposure therapy: In different contexts, including home. Over varying time lengths. With small amounts of drug use!

42. 42 7.3 Interim Summary Conditioning explains the development of drug tolerance and can lead to unexpected and sometimes fatal overdoses.