In 2367, while exploring a cavern on Alpha Onias III, Commander Riker was rendered unconscious by gases. While unconscious, neural scanners scanned 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 USS Enterprise-D, under the command of Captain Riker, explored the space beyond the Sargon Region. For this accomplishment, on stardate 55843, Riker was awarded the Preantares Ribbon of Commendation. In 2383, this region was mentioned in Riker's service record that was on display in his quarters on the Enterprise-D. (TNG: "Future Imperfect", okudagram)