If there a way to affect the action potential propagation across neurons, for better or worse? The organism I have in mind is planaria (flat worm) as they are very simple but can be conditioned (like the Pavlovian dog). I don't think that a non-harmful liquid chemical could have much effect, but is there another way, such as having a source of electricity near them? That's a stupid example, but I think you understand what I mean (I hope). Is there a way I could somehow inhibit the sodium potassium pumps, or the channels? EDIT: I'm just thinking... Would temperature have much of an effect? Proteins work slower under lower temperatures, don't they? Also, how many watts/volts/amps of an electrical current could they take? Would it matter?