The intermediolateral nucleus in sporadic amyotrophic lateral sclerosis.

Histological and morphometrical observations of the intermediolateral nucleus (IML) at the levels of the upper and lower thoracic segments (T2 and T9) were carried out in 18 patients with sporadic amyotrophic lateral sclerosis (ALS) and 15 age-matched control subjects. Of the 18 ALS patients 6 had been on a respirator before death. No Bunina bodies were found in the IML neurons in either the ALS patients or the control subjects. Only a small number of spheroids were encountered rarely in the IML in both the patients and controls. The number of neurons in the IML in the non-respirator-supported ALS patients were reduced at T2, but well preserved at T9 compared with the control subjects. In the respirator-supported ALS patients, there was a marked reduction of IML neurons at both T2 and T9. Considering the absence of direct synaptic contacts with anterior horn cells, these neurons, without the formation of Bunina bodies, appeared to be involved primarily in the disease process in sporadic ALS.