Degenerating compartment and functioning compartment of motor neurons in ALS: possible process of motor neuron loss

Using a morphometric method, we studied ventral spinal roots and anterior horn neurons of the fourth lumbar segment in 17 patients with ALS. Both populations of large myelinated fibers and anterior horn cells had significantly high correlations to muscle strength in the legs and duration of symptoms. However, active axonal degeneration was consistently present in terms of either large myelinated fibers or anterior horn cells.