Methods and systems for providing neuromodulation therapy are disclosed. The systems include an Implantable Pulse Generator (IPG) or External Trial Stimulator (ETS) that is capable of sensing an Evoked Compound Action Potential (ECAP), and (perhaps in conjunction with an external device) is capable of adjusting a stimulation program while based on the sensed ECAP. The stimulation program may include a pre-pulse component that may be adjusted based on the sensed ECAP. Moreover, stimulation may be applied to neural elements timed to coincide with the arrival of ECAPs at those neural elements. The stimulation may enhance or suppress activation of those neural elements.