Omnidirectional propulsion in a metachronal swimmer
Fig 6
Ctenophores are capable of several different swimming control strategies based on the activation of their ctene rows, which are controlled in pairs (such that each body quadrant receives one frequency input).
While each quadrant can operate at an independent frequency, we typically observe only two frequencies during turns, such that there is a single frequency differential (fout>fin). The above images schematically show (A) turning mode 1, (B) turning mode 2, (C) turning mode 3, and (D) straight swimming (mode 4).