Unconditioned anxiety

Among the most frequently used paradigms are tests for unconditioned anxiety that are thought to be indicative for human generahzed anxiety symptoms (Crawley 1999). In these tests, rodents usually are confronted with a novel environment or stimulus, and behavioral patterns related to anxiety (see Sect. 2.1.1) are measured. In the following, the most commonly used tests for unconditioned behavior will be briefly described. 

Probably the most frequently used test for unconditioned anxiety is the elevated plus maze (EPM), which was first introduced by File and coworkers (Pellow et al. 1985). The test consists of an elevated, plus-sign-shaped runway with two opposing arms being closed by walls and the other two arms being open, i.e., unprotected (Fig. 5). The animal usually is placed in the center of the EPM,... 

Another behavioral approach used to assess aspects of anxiety in animals relies on conflict paradigms in combination with punishment, mostly induced by electric foot shock. Due to ethical and also ethological considerations, paradigms based on electric shock are less often used than tests for unconditioned anxiety. However, it has been hypothesized that behavioral expressions displayed in tests for unconditioned and conditioned anxiety may reflect profoundly different aspects of anxiety (File 1995 Griebel 1996 Millan and Brocco 2003). Thus, shock paradigms are quite frequently included in behav-... 

Henniger MSH, Ohl F, HOlter SM, Weifienbacher P, Toschi N, Lorscher P, Wigger A, Spanagel R, Landgraf R (2000) Unconditioned anxiety and social behaviour in two rat lines selectively bred for high and low anxiety-related behaviour. Behav Brain Res 111 153-163... 

Referred to as a conditioned fear paradigm, the fear potentiated startle response was first described by Brown et al. (1951). In the original test, an acoustic stimulus is presented in the presence of a conditioned stimulus that has previously been paired with an aversive, unconditioned stimulus. The amplitude of the acoustic startle response is thought to indicate the degree of conditioned anxiety, which can be reduced by anxiolytic drugs (Davis et al. 1993 Hijzen et al. 1995). 

Pavhvian conditioning explains behavior as reflexive in nature. The traditional example is of dogs salivating when a stimulus, a bell, is paired with the presentation of food. After repeated pairings, Ivan Pavlov found the conditioned or learned stimulus produces the same response as the unconditioned or natural stimulus. An example of this type of motivation is the fear and anxiety people feel when they enter a location where they have been injured. The location becomes a conditioned stimulus or cue producing the natural emotional response. 

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