Ultrastructural observation on the thalamic neuronal inclusions in young mice.

Neuronal intracytoplasmic inclusions were found in the ventrolateral and posterior nuclei of the thalamus of 3-month-old thiamine-deficient mice and quaking mice. An electron-microscopic study revealed that these inclusions were composed of condensation of parallel rectilinear 10-nm filaments with interconnecting cross-bridges as a hallmark of neurofilaments. They were morphologically indistinguishable from those described in aged mice. This observation indicates that neuronal inclusions in the thalamus, which have been constantly reported in aging mice, can be seen even in young mice in the presence of cellular metabolic disturbances.