Fig. 1. mi34 Mutant Zebrafish Exhibit Defective Swimming but CNS Output is Normal.

(a) Touch evoked swimming in wt but not stac3^mi34 embryos (48 hpf). Panels show superimposed frames (30 Hz) of swimming motion from wt sibling and stac3^mi34 embryos with heads embedded in agar. (b) Voltage recordings with 6 mM curare showing that touch evoked synaptic responses of slow twitch (wt sib: n=5; mut: n=6) and fast twitch muscles (wt sib: n=6; mut: n=4) of wt sibling and stac3^mi34 mutants (48 hpf) are comparable. Arrowhead denotes tactile stimulation. (c) Voltage recordings with no curare showing that mutant fast twitch muscles (48 hpf) respond to tactile stimulation with a burst of action potentials (n=8).