Fig. 9. Diagram of motor control and function of fast-start behaviors, modified from fig. 5 of Domenici and Blake (1997). The designations of whole-body S-start versus caudal S-start reflect the differences in rostral bending during the initial movements of strike and startle behaviors. This work confirms the role of an independent S-start behavior that functions as a startle and demonstrates differences in the motor control of strike and startle behaviors. While there are indications that these behaviors are controlled by different, but possibly overlapping, neural circuits, neural mechanisms have yet to be identified.