The cast for the week is listed in the end credits. The main players are also listed in the title sequence. Normally, the end credits should trump the shorter credits in the title sequence. But IMDb currently lists the main players in the order they appeared in the title sequence, and then lists the other players who are credited only in the end credits.
As always, some actors are credited who don't appear in the present episode. These actors are listed on IMDb as credit only. Any actor who appears but isn't credited is listed as uncredited.