Characterization of ChR2-EYFP expression in VGAT-ChR2(H134R)-EYFP line 8 BAC transgenic mice.

<p>(<b>A</b>) Transverse sections of the spinal cord at the thoracic (Ai) and lumbar level (Aii). In green endogenous GFP expression, which is similarly distributed both at the thoracic and lumbar spinal levels. (<b>B</b>) Immunostaining and co-localization. First column: DAPI staining; Second column: anti-GFP staining; Third column: anti-GAD67 staining (first row) or anti-GLY staining (second row); Last column: merged image of DAPI, anti-GFP and anti-GAD67/anti-GLY staining. Scale bar: 10 µm. (<b>C</b>) Multiunit responses upon light stimulation of the spinal cord. (<b>D</b>) Identified single neuron. Single neuron responses in the spinal cord were evoked both by stimulation of the muscle, of the foot and by optically stimulating the same area of the spinal cord where the electrode was inserted. As soon as the light was moved away from the electrode (color coded) - with a distance greater than 1 mm - the response to the light stimulation was no longer present.