a Double staining of NeuN and Iba1 on horizontal sections of the lesioned spinal cord at 14 DPL. Iba1 acts as microglia marker and represents the intensity of the immune response. b Double staining of GFAP and MAP2 on horizontal sections of the lesioned spinal cord at 14 DPL. MAP2 and GFAP indicate neuronal fibers and astrocytes, respectively. m, o, x, z regions in (a, b) denote neuron-lost areas adjacent to lesion sites (n, y). c–d″″ Horizontal images of the lesioned spinal cord shown double staining of mCherry and NeuN on slices from mice infected with the control virus AAV–mCherry (c–c″″) or AAV-Neurog2/mCherry (d–d″″) on day 4. e–f″″ Horizontal images of the lesioned spinal cord show double staining of mCherry and NeuN on slices from mice infected with the control virus AAV–mCherry (e–e″″) or AAV-Neurog2/mCherry (f–f″″) on day 30. Panels (c″″, d″″, e″″, f″″) are higher magnifications of the boxed areas in (c″′, d″′, e″′, f″′), respectively. mCherry was not colocalized with NeuN (arrowheads), mCherry colocalized with NeuN (arrows). Arrows and arrowheads in (c″″, d″″, e″″, f″″) represent mCherry+NeuN+ cells and mCherry+NeuN- cells, respectively. Scale bars: 50 μm (c″′, d″′, e″′, f″′) and 25 μm (c″″, d″″, e″″, f″″). g The statistical data of astrocyte-to-neuron conversion efficiency induced by Neurog2 at 30 DPI. A two-tailed t-test was applied. *** Represents p < 0.001; h 3D images of (f″″″) view: left view with 30° rotation (left), front view (middle), top-side view with 30° rotation (top), and right-side view (right). The red arrows in (f″″, h) show a typical view of the same cell.