Rhythmic flexor and extensor EMG bursts were generated by a region spanning the C3 ventral root (∼8 mm long). Thebox in the schematic illustration of the surgery (A) highlights the isolated region. C3 dorsal root was cut. The rest of the cord, including the contralateral side, was removed. This isolated region produced rhythmic flexor and extensor bursts through the C3 ventral root in the presence of 80 μm NMDA (B). Auto-correlation analysis confirmed the rhythmicity of the flexor (C) and extensor (D) bursts. Cross-correlation analysis revealed the coupling of the flexor and extensor activation with a time delay of ∼1.2 sec (E).