Inactivation of the lateral septum blocks fox odor-induced fear behavior.

A number of lesion studies have shown that the lateral septum plays an important role in the modulation of innate fear. Furthermore, an increased c-fos expression in the lateral septum was demonstrated after exposure to natural predator odors and 2,3,5,-trimethyl-3-thiazoline (TMT), a component of fox odor. This study investigates, on a behavioral level, whether the lateral septum plays a role in TMT-induced fear. Temporary inactivation of the lateral septum by local muscimol injections clearly blocked TMT-induced fear behavior but had no effect on behavior in a controlled condition. This indicates that the lateral septum is important for the processing of TMT-induced fear and suggests that the lateral septum is also involved in fear behavior induced by natural predator odors.