Fear Conditioning

Purpose

To measure aversive and associative learning and memory.

Description

Fear conditioning is the method by which organisms learn to fear new stimuli. It is a form of learning where fear is associated with a particular neutral context (e.g., a room) or neutral stimulus (e.g., a tone). This can be done by pairing a neutral stimulus with an aversive stimulus (e.g., a shock, loud noise, or unpleasant odor). Eventually the neutral stimulus alone can elicit a state of fear. In classical conditioning the neutral stimulus is the "conditioned stimulus" (CS), the aversive stimulus is the "unconditioned stimulus" (US), and the fear is the "conditioned response" (CR). Screening gene-modified mice or new drugs in the fear conditioning paradigm will elucidate molecular and biochemical neuronal mechanisms of learning and memory. Figure 1 demonstrates that performance in the contextual fear conditioning is not dependent on the presence of the rd1 mutation which causes blindness in mice (Clapcote et al 2005. Effects of the rd1 mutation and host strain on the hippocampal learning in mice. Behaviour Genetics, v. 35 (5): 591-601).

Figure 1. Fear conditioning performance of the CBA/CaJ (n=16), CBA/J (n=16), C3A.BLiA (n=16) and C3H/HeJ (n=16) strains. (a) Contextual fear conditioning. Activity in the context is shown as the percentage of baseline (test nave) activity during training (mean ± S.E.M.), a low value being indicative of contextual learning.

Figure 2A. Bax deficiency affects age-related changes in cognitive function. (A) Aged(15–17mo) KO females exhibit a deficit (lower freezing values) in the contextual fear conditioning when compared with age-matched WT (+/+) animals.

Figure 2B. (B) Bax-KO mice expressed no difference in the cued fear memory in comparison with WT littermates. (Perez et al 2007, Absence of proapoptotic Bax protein extends fertility and alleviates age-related health complications in female mice. PNAS 104 (12):5229-5234.)