Three experiments examined the acquisition, retention, and latent inhibition of odor-guided fear conditioning in rats. The results of Experiment 1 indicate that forward conditioned stimulus (CS)-unconditioned stimulus (US) pairings resulted in robust freezing responses to subsequent presentation of the CS alone. In Experiment 2, rats in one group (PRE) received unreinforced preexposures to the odorant CS, and those in a second group (NON) were not preexposed to the odorant. All rats then received forward CS-US pairings. PRE rats exhibited a marked attenuation of freezing to subsequent exposure to the CS relative to NON rats. All rats were then retested at one of the following posttraining delays: 17, 24, or 31 days. Freezing behavior of the NON rats declined significantly across these delays, whereas rats in the PRE group froze no more at any delay than they had 24 hr after training. Experiment 3 examined the contextual specificity of latent inhibition. Only those rats that were preexposed and trained in the same context exhibited latent inhibition. These results indicate that odor-guided fear conditioning is a robust and useful paradigm suitable for future studies of the neural bases of associative learning.When a nominally neutral stimulus (a conditioned stimulus [CS]) is paired with an aversive unconditioned stimulus (US), such as mild footshock, subsequent exposure to that CS typically elicits in rats a constellation of behaviors including freezing, increased blood pressure, defecation, and increased levels of adrenal hormones (reviewed by LeDoux, 1995). Together, these behavioral indices of conditioning frequently have been used to assess both the behavioral and neural bases of conditioned "fear." Most researchers examining conditioned fear in rodents have used auditory (Davis,

No abstract