Fig. 2A. Depolarization of cell SE1 (middle trace) with a short duration (1.2 s) current pulse produces a high frequency burst of action potentials (average frequency = 62 Hz) that initiates swimming. Note that membrane potential oscillations in cell 208, a swim oscillatory interneuron (bottom trace), and bursts of action potentials in the dorsal posterior (DP) of M13 begin almost immediately after intracellularly depolarizing cell SE1. Swimming in this and all subsequent figures is indicated by rhythmic bursts of actions potential in DP nerves (Kristan et al. 1974). During swimming the membrane potential of cell SE1 depolarizes 2 - 3 mV from rest (dashed line indicates the resting membrane potential of cell SE1) and its firing frequency increases from that before the onset of swimming. Membrane potential of cell SE1 returns to its resting level when swimming ends. Vertical scale bar pertains to both the middle and bottom traces.Return to results