[en] The relative emission cross sections for the (4,1), (4,2), and (5,2) bands of the N₂ first positive system were measured in the threshold region using a high energy-resolution electron spectrometer coupled to an optical detection system. The maxima in the relative emission cross section for the (4,1) and (4,2) bands occurred at 10.68 +- 0.08 eV and the maximum for the (5,2) band occurred at 11.00 +- 0.08 eV. Structure was observed in the excitation functions which arose from the presence of channels for the population of the N₂ B ³Pi/subg/ state other than direct excitation by electron impact at certain energies. The contribution from C ³Pi/subu/→B ³Pi/subg/ cascade is the major source of additional B ³Pi/subg/ state population. The contribution from this process reaches a maximum at an incident electron energy near 14 eV. The E ³Σ⁺/subg/ state is observed to contribute slightly to the B state population near 12 eV through cascade and/or collisional deactivation. A third secondary feature is observed in the optical excitation functions close to threshold. Measurement of direct electron excitation functions for the v=4 and v=5 vibrational levels of the B ³Pi/subg/ state by electron scattering techniques as well as delayed coincidence optical experiments on the first positive (4,1) band emission confirm the presence of a secondary process in this region. Radiative cascade from the N₂ A ³Σ⁺/subu/ and/or W ³Δ/subu/ states is the most reasonable explanation of this effect