An image based on the sketch of the stages of an avoiding reaction drawn by Jennings (1906). Anterior mechanical
stimulation by a cell swimming into an object leads to depolarization, opening
of the Cav channels of the cilia, movement of the cell backward for a
short time, twirling in place, and forward movement of the cell in a new
direction. Depolarization by ionic stimuli causes the same avoiding reaction
behavior. From Figure 5 of Eckert R (1972)
“Bioelectric control of ciliary activity.” Science 176:
473–481, copyright 1972, with permission from Science.