There are three basic categories of Flight Simulation Training Devices (FSTD, the name covering everything ground-based in which you can log time, take practical tests or other checkrides, or use for recent experience):
- Flight Simulator
- Flight Training Device
- Aviation Training Device (subdivided into Basic and Advanced)
14 CFR 61.51(g)(4) covers them
all. So, if it's authorized per 61.4/Part 60 to use for recent experience, then per 61.51, an authorized instructor must be present to observe that time and sign your logbook or training record or it's as though it didn't happen.
BTW, I doubt if you're really using a flight simulator -- much more likely an FTD or ATD unless you're doing this a big box that is moved around by large hydraulic power systems at an airline training center or the like, but even then, an authorized instructor's presence and signature are required for it to count.