Defensive behaviors such as flight and freezing are essential for animal survival in danger of threats.  In recent years, my lab has been interested in neural circuits underlying the generation and modulation of defensive behaviors evoked by sensory stimuli.  We are using a variety of tools, including optogenetics, chemogenetics, retrograde and anterograde neural tracing and in vivo electrophysiological recordings to dissect circuits for defense related behaviors as well as to understand how neurons along the pathways interpret the sensory signals.  I will present our research results on corticofugal controls of different types of defense behavior and regulation of the behaviors via a subthalamic nucleus in context dependent manner.