Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A scientific fact is not true.

On the bottom of page 19, Valerie Hunt says: "In the physical body there are two primary electrical systems. One is the well-known alternating electric current of the nervous system ..." In the nervous system there are no alternating currents, that is, a current that constantly reverses its direction. In the nerve there is an 'action potential' that travels in one direction only. When the 'action potential' of the nerve reaches the synapse of the target neuron, it releases a neurotransmitter into the synapse which fits into a receptor molecule on the surface of the target neuron. This in turn releases a second messenger in the cell. The neurotransmitter is then broken down and re-synthesized in the nerve terminal. There is no return of the 'action potential' to the original neuron.