Figure 1. Neural circuity for defense. Motivating stimuli activate the "defense zone" of the amygdala (neophobia? defense pheromones?), pretectum (moving visual stimuli), auditory pathways (sudden noise), and pain and tactile pathways. These motivating influences converge on input neurons of the midbrain central gray, which, in turn, activate neurons of a motivational mechanism for defense. The defense motivational mechanism activates motor patterning mechanisms for striking (in the cat), lunge-and-bite attack, upright and sideways postures, squealing and hissing, freezing, and fleeing. In most cases these mechanisms do not produce motor patterns unless they simultaneously receive appropriate visual or tactile releasing inputs, or, in the case of fleeing, releasing inputs from striatal-thalamic guidance mechanisms. Also illustrated is a motor patterning output to the pituitary-adrenal axis.