(a) Maximal GCaMP3 calcium fluorescence change of mCherry+ (n=20 from 5 fish) and mCherry- (n=33 from 5 fish) neurons in response to magnetic field stimulation. Dashed line indicates average GCaMP3 fluorescence value for mCherry- neurons. (17/20 mCherry+ neurons exceed this fluorescence value). Unpaired two-tailed t-test, (t51=3.373, p=0.0014). (b) Schematic of behavioral paradigm for induction of zebrafish coiling behaviors using magnetic stimulation. (c) Schematic of Rohon-Beard neuron projections. (d) Magneto2.0 expression construct. Tol2: transposon site; ngn1: neurogenin-1 promoter; IRES: internal ribosomal entry site; nls: nuclear localization signal; EGFP: enhanced green fluorescent protein; polyA: polyadenylation signal. (e-f) In vivo imaging of Rohon-Beard neuron projections into the skin, n=10 fish examined per genotype. Inset: Magneto2.0+ (EGFP+/RFP+) and Magneto2.0- (EGFP–/RFP+) neurons. Data pooled from 2 injections per genotype. **p<0.01. Data shown as mean±SEM.