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. Author manuscript; available in PMC: 2022 Mar 22.
Published in final edited form as: Science. 2022 Feb 10;375(6581):639–647. doi: 10.1126/science.abh0474

Fig. 2. Optogenetically induced BCF propulsion.

Fig. 2.

(A) Upon alternating blue and red light stimulation, the biohybrid fish induces contraction of the ChR2- and ChrimsonR-expressing muscles, respectively. (B to G) Body kinematics and hydrodynamics of the biohybrid fish during one and a half tail-beat cycles. (B and F) Peak contraction of left muscles. (C and G) recovery to straight position. (D) peak contraction of right muscle. (E) recovery to straight position. Left and right muscles work antagonistically against each other, leading to rhythmically sustained body and caudal fin (BCF) propulsion. PIV flow measurements highlight the shedding of the positive and negative vortex pair at every lateral tail excursion. (H) Corresponding midline kinematics (time step: 50 ms). (I to K) Kinematic analysis of seven strokes; correlation between optogenetic muscle activation and BCF locomotion (n = 7 strokes; data represent mean ± SEM). (J) aCurvature of the midline; (K) moving distance. (L) Positive relationship between pacing frequency and moving speed of optogenetically stimulated biohybrid fish [n = 31 videos from seven stingrays (3); 27 videos from six rat fish; and 54 videos from 12 human fish.] Data represent mean ± SEM).