The occurrence of dark neurons in the normal and deafferentated lateral vestibular nucleus in the rat: observations by light and electron microscopy.

The lateral vestibular nucleus was studied by light and electron microscopy in normal rats as well as in rats in which the anterior cerebellar vermis was destroyed. Dark neurons were seen in many of the operated rats but were rarely found in normal control animals. The dark neurons were not seen in adjacent nuclei. In additional rats, it was found that anoxia, extra anaesthetic, postmortem rough handling, and sham operations did not increase the frequency of dark neurons. These data indicate that dark neurons might not always be artifactual and that the lateral vestibular nucleus appears to be a focal point for their occurrence.