Experimental setup.

<p>(<b>A</b>) Anatomical landmarks (i.e., sacrum, iliac crest, and spinous processes) for localization of the lumbar spine (L2–S1); (<b>B</b>) Lateral view of anatomical motion analysis markers (1-Lateral iliac crest, 2-Trochanter major, 3-Patella, 4-Lateral malleolus, 5-Fourth metatarsal); (<b>C</b>) Pre-operative computed tomography: Lower thoracic vertebrae, lumbar vertebrae and sacrum; (<b>D</b>) Exposure of the lumbar spine; (<b>E</b>) Laminotomy at L5-left (circle) and epidural electrode (arrow); (<b>F</b>) Exposure of the spinal cord for intraspinal microstimulation; (<b>G</b>) Typical microelectrode implantation in the left hemicord (arrow). Insulating adhesive tape was used for protection of the electrode during forceps-insertion and color-coded to determine insertion depth (e.g., blue tape corresponded to an electrode depth of 6 mm). A reference ruler (centimeters) was used to determine cord dimensions and estimate electrode location.</p

Targeting analysis and functional outcomes.

<p>(<b>A</b>) Epidural electrode placement confirmed by lateral intra-operative fluoroscopy; (<b>B</b>) Posterior-anterior intra-operative fluoroscopy; (<b>C</b>) <i>Ex-vivo</i> axial MRI of spinal cord showing ISMS electrode tract (arrow); (<b>D</b>) Experimental setup for kinematic analysis; (<b>E–F</b>) Typical hip extension evoked by ISMS at L5-segment; (<b>G</b>) Normalized intramuscular EMG amplitude as a function of spinal cord segment evoked by ISMS at 300 µA (n = 3); (<b>H</b>) Kinematic analysis of joint angle change evoked by ISMS as a function of spinal cord segment (n = 3). Abbreviations: G.M. = Gluteus medius, H = Hamstrings, B.F. = Biceps femoris, G = Gastrocnemius, Q.F. = quadriceps femoris.</p