Fig. 6

Increased loss of synapses at the site of clinical onset. a Representative images (synaptophysin immunoreaction in 50 µm paraffin sections) and high magnification inset of lumbar and cervical spinal cord from a case with lumbar onset (Table 1, Case No 15). b Synaptic area (lamina IX) in lumbar and cervical spinal cord sections from cases with lower limb onset; synaptic loss is either comparable in lumbar and cervical, or more extensive in lumbar; each datapoint represents an independent ROI in the sections, and for each subject ROIs in lumbar and cervical spinal cord are displayed. c. High correlation between synaptic loss in lumbar and cervical spinal cord in cases with lower limb onset. d Representative images and high magnification inset of lumbar and cervical spinal cord from a case with upper limbs onset (Table 1, Case No 26). e Synaptic area (lamina IX) in cervical and lumbar samples from subjects with cervical/bulbar onset; each datapoint represents an independent ROI in the sections, and for each subject ROIs in lumbar and cervical spinal cord are displayed. f High correlation between the synaptic loss in cervical and lumbar sections of spinal cord in subjects with upper (cervical/bulbar) onset. Data information: data are presented as means ± SD. ns, p > 0.05; *, p < 0.05; **, p < 0.01; and ***, p < 0.001 (one-way ANOVA with Tukey’s test for multiple comparisons)