In 2367, while exploring a cavern on Alpha Onias III, Commander William T. Riker was rendered unconscious by gases. While unconscious, neural scanners scanned Commander William T. Riker's brain. The scanners used elements of Riker's reality and constructed a holodeck simulation with those elements interspersed throughout, so that it felt real to him. What Riker wanted, the scanners made possible.
In one of these simulations, the Deneva Special Congress on Interstellar Affairs was where conference delegates discussed deep space exploration and Federation security. Captain Riker of the USS Enterprise-D acted as a special representative for the Federation at this congress. In 2283, this congress was mentioned in Riker's service record that was on display in his quarters on the Enterprise-D. (TNG: "Future Imperfect", okudagram)