Omnipause neurons in two cases of opsoclonus associated with oat cell carcinoma of the lung.

Opsoclonus is an involuntary eye movement disorder in which there are chaotic, usually conjugate, multidimensional saccadic eye movements. In this paper 2 cases of opsoclonus are reported, as a paraneoplastic phenomenon in association with oat cell carcinoma of the lung. It has previously been hypothesized that opsoclonus results from dysfunction of a group of premotor neurons in the brainstem called omnipause neurons. We describe the location of these cells in man by homology with animal studies, and describe the light microscopic appearance of these neurons in the 2 cases of opsoclonus. Although these neurons appeared normal it is still possible that their function was disturbed as a result of metabolic or neurotransmitter abnormalities.