Aversive stimuli

Lysle, D.T.,et al., Characterization of immune alterations induced by a conditioned aversive stimulus, Psychobiology, 18, 220, 1990. 

Lysle, D.T., Luecken, L.J., and Maslonek, K.A., Modulation of immune function by a conditioned aversive stimulus Evidence for the involvement of endogenous opioids, Brain, Behav. Immun., 6, 179, 1992. 

In a fear-conditioning experiment, a neutral stimulus, such as a tone or a light, is paired with an aversive stimulus, such as a shock, a loud noise, or an aversive air blast. Following this experience, the formerly neutral stimulus becomes a conditioned stimulus (CS-F) and acquires the ability to elicit behaviors and physiological responses formerly only associated with the aversive stimulus, the unconditioned stimulus (UCS). Enthusiasm for this work derives at least partly from the precise delineation of neural circuits, down to the level of the genome, engaged by environmental components that produce fear conditioning (LeDoux,... 

S tin us, Louis, Michel Le Moal, and George F. Koob. 1990. "Nucleus Accumbens and Amygdala Are Possible Substrates for the Aversive Stimulus Effects of Opiate Withdrawal." Neuroscience 37 767-73. 

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... 

Passive avoidance tasks, where the animal is required to refrain from doing something in order to avoid an aversive stimulus, do not usually show a lead effect (Cavanagh et al, 1984). 

---