Many things could go wrong but first and for most is to carefully follow the necessary steps of electrode placement & experiment configuration described in the Procedure in the link bellow.

If your still experiencing difficulty getting spikes with your worm then remember to use a non-conductive probe like plastic or glass to tap the worm. Also make sure the worm is not excessively wet as that can cause an electrical artifact short and take a look at the pics bellow for electrode placement and tapping positions.

For more information about the experiment check a science paper we've released about the whole protocol and detailed science behind it.