Nervous system would not exist without the human brain. Most neurons send signals via their axons, although some types are capable of dendrite-to-dendrite communication. (In fact, the types of neurons called amacrine cells have no axons, and communicate only via their dendrites.) Neural signals propagate along an axon in the form of electrochemical waves called action potentials, which produce cell-to-cell signals at points where axon terminals make synaptic contact with other cells. Synapses may be electrical or chemical. Electrical synapses make direct electrical connections between neurons, but chemical synapses are much more common, and much more diverse in function. At a chemical
The Stealers of Dreams typical. Then the Doctor is there, and asks to talk to him, go into the building and try to help. Once the Doctor gets inside, Jack fills him in on what's happening. Rose is in a room, still unsure of herself. The Doctor tells her about the microorganisms, how they feed off electrical activity, and seem to just love the neuroelectro-chemical signals put out by the right side of adult human brains. They create a feedback loop, which passes to the left side and causes a person to become 'fantasy-crazy.' He tells her that now that she understands what is