assuming the possibility, id like to throw a little bit of physics into the mix.
my guess would be that if its at all possible, somehow one could utilize the energy or just the plain current from the firing of neurons in our mind (as TheAgeofReason said). perhaps, through a change in energy mediums, (i.e. liquid to gas, yet on the same level, electricity being transferred, perhaps in some undiscovered or proven form???). one could even include the possibility of dark matter taking effect. its literally everywhere, as a sort of negative form of matter. perhaps, the dark matter portion of our brains could operate across planes, affecting matter and dark matter simultaneously???!?!?!?!!
oh jeebus, im outdoing myself here

its all just guesswork in the end.