Learning classical conditioning

Taken together, this body of work demonstrates that adult behavioral responses to social odors are shaped by early olfactory experience. Indeed, heterospecific or artificial odor cues associated with the rearing environment acquire attractive properties that can last into adulthood in many rodent species. Furthermore, early experience with opposite-sex odors appears to be critical for the normal development of appropriate behavioral responses to sexual odors in mice and hamsters. Importantly, the behavioral plasticity observed using these different experimental approaches may all be mediated by a classical conditioning model of olfactory learning. The experience-dependent development of odor preference in rodents therefore provides a powerful model for understanding how the olfactory system recognizes and learns the salience of social odors, a function that is critical for the appropriate expression of reproductive behavior. 

Einally, classical conditioning is pretty well known from Pavlov s famous studies of dogs many years ago. Pavlov demonstrated that when dogs were conditioned to associate an unpleasant stimulus with one that would usually elicit no response, they learn to react to the latter response. Thus, if the sound of a bell is quickly followed by an electric shock, and this is repeated a number of times, the dogs will learn to react (yelp, say) to the sound of the bell alone. The dogs have been conditioned to associate the sound of the bell with an unpleasant experience. 

The categories of methods used in behavioral toxicology fall into two principal classes, stimulus-oriented behavior, and internally generated behavior. The former includes two types of conditioned behavior operant conditioning, in which animals are trained to perform a task in order to obtain a reward or to avoid a punishment, and classical conditioning, in which an animal learns to associate a conditioning stimulus with a reflex action. Stimulus-oriented behavior also involves unconditioned responses in which the animal s response to a particular stimulus is recorded. 

Garcia L., D Alessandro G., Bioulac B., Hammond C. High-frequency stimulation in Parkinson s disease more or less Trends in Neuroscience, 2005, 28, 209-216. Garenne A. and Chauvet G. A. A discrete approach for a model of temporal learning by the cerebellum in silico classical conditioning of the eyeblink reflex. / Integr Neurosci, 2004, 3,301-18. 

Childress AR, McLellan AT, Ehrman R, O Brien CP (1988) Classically conditioned responses in opioid and cocainedependence a role in relapse. In Learning Factors in Substance Abuse NIDA Research Monograph 94, pp. 25-43. US Government Print Office, Washington, DC. 

With classical conditioning, however, there is more than simple learning involved. The dog may have learned that the sound of the bell would be followed by food, but it did not then have a choice to salivate or not. The salivation, the conditioned response, was automatic. A classically conditioned response has a mandatory quality about it, a compulsiveness, that is very powerful. 

E. Kandel and colleagues have studied the effects of environmental experiences and learning on the nervous system in the Aplysia (a marine mollusk). This animal is well suited for such a study because its nerve cells are quite large and easy to visualize. Also it does respond well to learning experiments such as habituation, sensitization, and classical conditioning (Pinsker et al. 1970). 

Thum AS, Jenett A, Ito K, Heisenberg M, Tanimoto H (2007) Multiple memory traces for olfactory reward learning in Drosophila. J Neurosci 27 11132-11138 Tully T, Quinn WG (1985) Classical conditioning and retention in normal and mutant Drosophila melanogaster. J Comp Physiol [A] 157 263-277 Tully T, Cambiazo V, Kruse F (1994) Memory through metamorphosis in normal and mutant Drosophila. J Neurosci 14 68-74... 

The use of blink reflex classical conditioning to investigate motor learning in subjects exposed to neurotoxicants has been suggested. Bekkedal et al. (2001) reported that the blink reflex conditioning response may be affected by exposure to JP-8. It has been shown that the cerebellum is involved in the... 

The two main types of learning paradigms are classic conditioning and instrumental conditioning. 

Sandoz, J., Roger, B. and Pham-Delegue, M.H. (1995). Olfactory learning and memory in the honeybee Comparison of different classical conditioning procedures of the proboscis extension response. C. R. Acad. Sci. Paris, Sci. Vie 318, 749-755. 

Classical conditioning is the acquisition of a behavioral response to a new stimulus by association with a previous stimulus. Contextual fear conditioning is a form of classical conditioning used to evaluate the learned response to an environment where the animal previously experienced an aversive stimulus. For example, rats freeze when placed in a chamber where they have previously been subjected to an electric shock. This freezing response is either absent or reduced in... 

The top half of Figure 7.4 depicts the sequence of stimulus-response events occurring in classical conditioning. Actually, before learning occurs, the sequence includes only three events—conditioned stimulus (CS), unconditioned stimulus (UCS), and unconditioned response (UCR). The UCS elicits a UCR automatically, as in an autonomic reflex. That is, the food (UCS) elicited a salivation reflex (UCR) in Pavlov s dogs. In the same way, the smell of popcorn (UCS) might make your mouth water (UCR), a puff of air to your eye... 

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