a Schema for acute stimulation of evoked compound action potentials. (Left) Current-controlled stimulation was delivered via a rostral nanoclip interface; evoked responses were recorded by a second nanoclip interface placed 15–20 mm caudally on the same nerve. (Right) Biphasic, cathodal-leading stimulating pulses, 200 μs phase−1 at 5–40 μA, were delivered at 1 Hz. b Example of graded evoked response to increasing stimulation intensities. Stimulation applied at t = 0 ms; stimulation artifact appears t = 0–0.5 ms; evoked response follows. Inset shows stimulation electrode configuration—“+” denotes source of cathodal first phase; “R” denotes electrodes for the current return path. c Evoked compound responses show that spatially distinct patterns of stimulation can produce a high degree of modulatory specificity. Inset shows the location of electrodes mediating stimulation pulses with cathodal (red) or anodal (blue) leading phases.