Vidugora is probably Vidugiriai. The JewishGen Gazetteer includes two communities in Lithuania with the name Vidugariai, both of which are near Panevezys (known under Russian rule as Ponevezh)::
|Vidugiriai, Vidugirtsy, Vidugirtsay
||55°38' N 24°55' E
||23.1 miles ESE of Panevė�ys (Ponevezh) 55°44' N 24°21' E
||55°45' N 24°58' E
||24.0 miles E of Panevė�ys (Ponevezh) 55°44' N 24°21' E
I can't tell which of these would be your grandfather's birthplace but now at least you have a starting place.
Good luck - Judith Singer