A neurogenic transmitter was a piece of technology that amplified and shared neurogenic fields.
The "Dream Aliens" in the Delta Quadrant used such a transmitter to induce a hyper REM state in others over interstellar distances. In 2374, the species captured most of the crew of USS Voyager via their neurogenic field, trapping them in a shared unconsciousness. They released the crew after Commander Chakotay threatened to destroy the cave where their real bodies resided. (VOY: "Waking Moments")
The device was not identified in the episode beyond the term "transmitter".