title: Summation and discrimination of gratings moving in opposite directions.
mesh_terms: D005556:Form Perception / Q000502:physiology*; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D013997:Time Factors; D014792:Visual Acuity