The smell of danger: a behavioral and neural analysis of predator odor-induced fear.

The odors of predators used in animal models provide, in addition to electric footshock, an important means to investigate the neurobiology of fear. Studies indicate that cat odor and trimethylthiazoline (TMT), a synthetic compound isolated from fox feces, are often presented to rodents to induce fear-related responses including freezing, avoidance, stress hormone and, in some tests, risk assessment behavior. Furthermore, we report that different amounts of cat odor impregnated on small-, medium-, or large-sized cloths impact the display of fear-related behavior when presented to rats.