Figure 1.

Experimental setup combining epidural cortical stimulation, epidural spinal stimulation, epidural spinal recording, invasive spinal recording, and EMG in rodent model. A, Representative cortical and epidural spinal stimulation pulse trains of 20 low-frequency pulses, with pulse width of 200 μs per phase and/or 40–200 μs per phase, respectively. B, Rat model depicting different electrodes sites. The right hindlimb representation area (HLA) of the motor cortex (M1) is stimulated using epidural bipolar stimulating electrode. Epidural leads are positioned on the midline of the spinal cord at T12–T13 segment and L1 vertebral segment to stimulate (orange) and record (gray) from the spinal cord, respectively. A four-shank silicon array (black) records the intraspinal responses. A reference electrode is placed under the skin. Percutaneous nickel-chrome wire electrodes (deinsulated 1 mm from the tip) bilaterally implanted into the tibialis anterior muscles record EMG responses. C, Epidural lead with four electrodes of 0.5-mm length each, separated by 1 mm. The diameter of the lead is 0.5 mm. D, Representative placement of the four-electrode epidural leads (contacts A, B, C, and D oriented as shown) along the spinal cord. Stimulating (orange) and recording (gray) epidural leads are placed at the T12 vertebral segment and L1 vertebral segment, respectively, with the interelectrode distance between electrode contact A of the epidural stimulating lead and electrode contact A of the epidural recording lead of 3 ± 1 mm. E, Cross section of spinal cord showing the placement of electrode for intraspinal recording. A four-shank Neuronexus silicon array is inserted transversely into the left side of the spinal cord to a depth of 1.7 ± 0.2 mm from the pial surface. Figure Contributions: Mahima Sharma, Vividha Bhaskar, John Martin, Tianhe Zhang, Rosana Esteller, Lillian Yang, and Nigel Gebodh designed the figure.