The intermediolateral nucleus and Clarke's column in Parkinson's disease.

Histological and morphometrical observations of the intermediolateral nucleus (IML) and Clarke's column at the levels of the upper and lower thoracic segments (T2 and T9) were carried out in 25 patients with Parkinson's disease (PD) and 25 age-matched control subjects. The average numbers of neurons in the IML at T2 and T9 in the PD patients were 69% and 57% of those in the controls, respectively. Lewy bodies were found in the remaining IML neurons in 24 of 25 cases of PD. On the other hand, the number of neurons in Clarke's column in the PD patients was not reduced. Considering that autonomic symptoms are one of the cardinal clinical features in PD, the present finding of IML neuron loss with formation of Lewy bodies appears to be of great importance.