Extended Data Fig. 2: Immunohistochemical staining of MN in spinal cords and schematic illustration of precise and fast motion analysis.

a, Immunohistochemical staining of NeuN or ChAT in adjacent sections from monkey spinal cords. Representative images of the vGM region (left) and the percentage of MNs or INs in total vGM neurons (right) are shown. The dashed lines show the boundary of the vGM region. NeuN, total neurons; ChAT, MNs; INs, NeuN-positive neurons minus ChAT-positive MNs. Scale bars, 100 μm. b, Immunohistochemical staining of ChAT or γ-H2A.X in the adjacent sections from young and aged monkey spinal cords. Representative images of the vGM region (left) and the percentage of γ-H2A.X⁺ MNs in total MNs (right) are shown. The arrows show the γ-H2A.X⁺ MNs. Scale bars, 100 μm. Scale bars (zoomed in), 20 μm. c, Immunofluorescence staining for 4-HNE and ChAT in the spinal vGM region from young and aged monkeys. Representative images (left) and the mean intensity of 4-HNE fluorescence per (ChAT⁺) MN (right) are shown. Scale bars, 20 μm. d, Immunofluorescence staining for H3K9me3 and ChAT in the spinal vGM region of young and aged monkeys. Representative images (left) and the mean intensity of H3K9me3 fluorescence per (ChAT⁺) MN (right) are shown. The dashed lines indicate the nuclei of MNs. Scale bars, 10 μm. e-f, Immunohistochemical staining of NeuN in spinal cords from young and aged monkeys. Representative images (e) and the percentage of total NeuN⁺ (left) or NeuN⁺ in dGM (right) in total spinal GM cells (f) are shown. The dashed lines show the boundary of the vGM and dGM regions. Scale bars, 200 μm. g, Bar plots showing the percentage of NeuN⁺ in vGM (left) in total spinal GM cells, as well as the percentage of NeuN⁺ in vGM (middle), and MNs (right) in total spinal vGM cells. A cell larger than 30 μm in cell soma diameter was considered a motor neuron in the spinal vGM. h, Co-staining of BTX and NF in neuromuscular junctions (NMJs) in skeletal muscle from young and aged monkeys. Representative images (left) and the percentage of nerve terminal area (BTX-positive) per 0.2 cm² or the percentage of axon area (NF-positive) per 0.2 cm² (right) are shown. Scale bars, 50 μm. i, Schematic illustration of precise and fast motion analysis with the joint detection and classification model with middle fusion approach (JDC-MF) network. A monkey was captured by three cameras. Deep learning algorithms and a 3D modelling approach were employed to accurately detect the monkey’s position, and to classify its actions into two types, analyse its upper limb activity, and estimate its motion in 3D space. j, Bar plot showing movement distance in four hours of young and aged monkeys. Data (a-h, and j) are shown as the mean ± s.e.m. P values were calculated using two-tailed unpaired t-tests. a.u., arbitrary unit. Three discontinuous cross-sectional slices per monkey (a-h). n = 8 monkeys per group (b-h). n = 16 monkeys per group (a). n = 8 in the young monkey group and n = 4 in the aged monkey group (j).

Source Data