Fig. 3. Graded interruption of swimming by increasing hyperpolarization of sint1. (A–D) The upper traces in A–D show activity in Rsint1 during a continuous episode of swimming. The lower traces show the animal's swimming movements. Hyperpolarizing currents were applied via the recording electrode using a bridge circuit. The timing of current pulses is indicated by solid bars drawn under the behavioral record, and the strength of the hyperpolarizing current is indicated under each bar. Changes in absolute membrane voltage during stimulation are inaccurate because of errors in bridge balance.