Construction of the intracellular stimulus train.
A) Relative timing of EODs and interfering events were selected from behavioral experiments files using a time resolution of 20 microseconds. From these data we constructed a file having three channels (in house software): Channel 1) the intracellular stimulus train, in which EOD-timed stimuli consisted of a rectangular pulse of 1.5 ms duration starting at the timing of the EOD (open rectangles) and the interference-timed stimuli consisted of a rectangular pulse of 1.5 ms duration starting at the timing of the interfering event (filled rectangles); Channel 2) the EOD timing monitor in which only EOD-timed stimuli were represented; and Channel 3) the interference timing monitor in which only interference-timed stimuli were represented. Channel 1 was used to drive the step activation port of the Axoclamp 2B. Intensity was controlled using Axoclamp 2B step activation controls. Channels 2 and 3 were recorded simultaneously with the voltage and current outputs of the Axoclamp 2B.