Yes, there are two simple methods.
(i) The DS2A has the ability to be gated by an external pulse i.e. when external control of pulse duration is selected the output stimulus timing will be controlled by the trigger-in stimulus pulse. It should be noted that (with a 5V input pulse) there is only a very short delay of <2µs for the turn-on and <6µs for the turn-off. When a typical TTL pulse is used, which will only be about 3V, these are matched at 4µs each.
(ii) Alternatively, if a trigger pulse is not available or exact timing is not crucial (for instance when lesioning or injecting dye, there is a jumper which can be set to allow the unit to deliver a current for the duration the single shot button is held down. The internal “Single” jumper determines the output delivered when the “SINGLE” button is pressed (when “EXTERNAL” Duration is selected).
“MON” (factory setting) produces a very short pulse ~10µs when pressed.
“CONT” produces an active output for the duration of the press. This could be useful in dye marking etc.