Achieving targeted and efficient neural excitation is one of the major challenges in the design of implantable electroceutical devices. In this study, we explore the potential of using direct-contact ultrasound to localize and enhance the process of electrical current stimulation. The underlying premise of this study is to use ultrasonic pulses to vary the non-linear capacitive element formed by the neural membrane which would result in an ionic charge-pump that would reduce the activation threshold for a subsequent electrical stimulation. We have tested this hypothesis using a phantom experiment where a millimeter-scale ultrasonic crystal was affixed directly to the sciatic nerve of a frog and was driven both by a continuous train and by a 5 ms train of 3 MHz pulses with a monophasic electrical stimulus pulse applied at varying latencies. Compound action potential amplitudes were recorded from the gastrocnemius muscle during dual-mode stimulation, and were compared to baseline amplitudes. The experimental results showed that a downward shift in strength-duration was evident, and that a larger latency between ultrasound and electrical stimulation appeared to produce a larger amplitude with respect to the baseline, while near-simultaneous stimulation showed a suppression of action potential amplitude.