Pre Record is different (and does not work for MIDI), it records a set amount before (manual) punch in. Studio One is able to record MIDI events Pre count. But that's also different, because you still planned a recording.
Retrospective always records. Whether in stop or playback mode. The buffer is flushed as soon as you playback again. It's very useful to capture spontaneous moments but can also speed up your work significantly, because you don't have to enable record, don't have to delete wrong takes, don't have to figure out that lick or CC change again that accidentally sounded very cool etc. In Cubase I hardly ever touch the record button when working with MIDI. I just play along. When I think I'm happy after the take, I press Shift-* to parse the buffer to the track.
I've shot a short video to show how it exactly works in Cubase.