Balanced biphasic monopolar stimulation induces rapid and cathode-directed galvanotaxis in undifferentiated neural precursor cells. (A, B, C) Neural precursor cells (NPCs) exposed to biphasic monopolar (BPMP) stimulation (n = 3) have a greater magnitude of velocity (|velocity|) (A) and directedness (B) and a lower tortuosity (C) of migration compared with nonstimulated NPCs (n = 3), and a greater |velocity| (A) and directedness (B) compared with biphasic bipolar (BPBP)-stimulated groups (n = 3). (D, E, F) Individual cell migration tracks localized to a common origin show that undifferentiated NPCs migrate toward the cathode terminal in the presence of BPMP pulses (D), but undergo nondirected migration in the presence of BPBP stimulation (E) or in the absence of stimulation (F). (G, H, I, J, K) NPCs maintained in the presence of epidermal growth factor, basic fibroblast growth factor and heparin express nestin, but not β-III tubulin (G, H), or glial fibrillary acidic protein (GFAP) (I, J), prior to (G, I) and following (H, J) 6 hours of time-lapse imaging when exposed to biphasic electrical stimulation, or when not stimulated (K). (G′, H′, I′, J′, K′) Higher magnification images of the regions within the dashed boxes in (G) to (K). Scale bars = 100 μm. Data presented as mean ± standard error of the mean. *P <0.05.