By a motor hallucination, I mean the illusion that we are actually moving when there is no peripheral excitation of the motor organ.

Just as the centres concerned in passive sensation are susceptible of central stimulation, so are the centres concerned in muscular sensation.

A mere impulse in the centres of motor innervation (if we assume these to be the central seat of the muscular feelings) may suffice to give rise to a complete representation of a fully executed movement.

And thus in our sleep we seem to walk, ride, float, or fly.
The most common form of motor hallucination is probably the vocal.

In the social encounters which make up so much of our sleep-experience, we are wont to be very talkative.