Fear Conditioning


Fear conditioning is an experimental procedure in which an organism is taught to fear a harmless, neutral stimulus, such as a tone. Conditioning is accomplished by pairing the neutral stimulus with an aversive stimulus, such as a foot shock. After a few associations, the animal comes to exhibit fear responses whenever the tone is presented, representing learning. In rats, these responses include freezing and an elevation of blood pressure and heart rate which are almost identical to the types of physiological and behavioral responses displayed by humans with phobias or unexplained irrational fears.
Emotional arousal in the laboratory has been examined under two major types of conditions: fear conditioning (as described above) and a task known as the inhibitory avoidance task, which is described elsewhere on this web page.
The specific role of a brain structure known as the amygdala in these procedurally unique learning tasks has been the subject of some debate. Two roles for the amygdala have been suggested. One position views the amygdala as the locus of emotional memory, where it is required for learning associations in new emotional situations, (i.e. acquisition), storing the associations into a more permanent form (i.e. retention), and expression of emotional memories through appropriate behavioral responses. The other position considers the amygdala as a critical modulator of the neural processes that are necessary for newly learned information to be consolidated or stored in other areas of the brain where long-term memories may be localized.
Fear conditioning procedures and the inhibitory avoidance learning task both appear to be evaluative tasks for fear learning and memory. Thus, if a common neural pathway mediates both, it would follow that experimental manipulations that influence one would have a similar effect on the other. Conversely, if different underlying neural pathways are responsible for each type of learning, then a difference in results might occur from similar experimental methods. It is the goal of experiments conducted in this laboratory to provide further insight into the nature of fear conditioning and how it relates to inhibitory avoidance.

Cedric Williams
The University of Virginia
Psychology Department

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