Fig. 4

Increased Synaptic loss in cases with advanced neuropathological brain stage. a-c. Synaptic area in laminae I-II (a), lamina VII (b), lamina IX (c) of lumbar (L4-5) SC for each ALS case, subdivided according to their neuropathological brain stage. No difference is found in synaptic density in lamina II and VII across the stages; in lamina IX, a significant decrease is found for patients in stage 5, although substantial variability is observed in stages 2 to 4. d–f Synaptic area in lamina I-II (a), lamina VII (b), lamina IX (c) of cervical (C3-C4) SC for each ALS case, subdivided according to their neuropathological brain stage. No difference is found in synaptic density in lamina II and VII across the stages; in lamina IX, a significant decrease is found for patients in stage 5, although substantial variability is observed in stages 2–4. g-i. Synaptic area in laminae I-II (g), lamina VII (h), lamina IX (i) of thoracic (T11-12) SC for each ALS case, subdivided according to their neuropathological brain stage. No difference is found in synaptic density in lamina II and VII across the stages; in lamina IX, a significant decrease is found for patients in stage 5, although substantial variability is observed in stages 2 to 4. Each subject is depicted as a single datapoint, average of the multiple ROIs. 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)