I'm writing a scifi story about a human undergoing rapid evolution due to his being repeatedly "connected" to an alien biological machine,that would be controlling the evolution through some kind of program. one of the changes would be a "master" cell that was able to regulate clusters of neurons from a distance. It would be able to selectively "turn off" other neurons in the brain through a targeted electromagnetic pulse. The idea is that it would act like transcranial magnetic stimulation only far more sophisticated. Leading to far more complex interactions between the cells. It would lack the ability to receive input from neurotransmitters but would still be powered by a voltage gradient. Perhaps, input would come from a magnetite core that detected surrounding electrical activity and then responded based on some biological algorithm. Output could be produced by ferrite? My biggest concern is that it would be impossible for a cell to produce a powerful enough pulse to effect change at distances greater then what could be achieved by a normal neuron with dendrites.