title: Vigilance, the psychological refractory period, and brain stem multiple-unit activity.
mesh_terms: D000818:Animals; D001288:Attention; D005071:Evoked Potentials; D000882:Haplorhini; D008027:Light; D008636:Mesencephalon / Q000502:physiology*; D011930:Reaction Time; D012154:Reticular Formation / Q000502:physiology*; D013997:Time Factors