Relay neuron
A relay neuron (also known as an interneuron) passes signals between neurons. They recieve a signal from one neuron and then transfer the signal to another neuron. They act like a relay messenger.
Becker W., Hardin J., Bertoni G., and Kleinsmith L. (2012) Becker’s World Of The Cell, 8th Edition, San Francisco: Pearson Education. Page 365