The structure of the occupied states of single-crystal Nd_1.85Ce_0.15CuO₄ has been studied by means of ultraviolet photoemission spectroscopy (hv=8.43 eV). A number of features are observed for the first time in the binding energy range E_CB<4 eV. An analysis of the evolution of the spectra during thermal and photoactivation treatment of the single crystal in ultrahigh vacuum and in oxygen has revealed electron density of states peaks due to the oxygen orbitals in the Cu-O planes.