Distribution and size of cerebellar and thalamic projection neurons in the trigeminal principal sensory nucleus and adjacent nuclei in the rat.
Using retrograde axonal transport of wheat germ agglutinin conjugated with horseradish peroxidase (WGA-HRP), the distribution and size of the cerebellar and thalamic projection neurons were demonstrated in the trigeminal principal sensory nucleus (Vpr) and four adjacent nuclei: the trigemino-angular nucleus (Ta), the supratrigeminal nucleus (SupV), the intertrigeminal nucleus (IntV) and the juxtatrigeminal nucleus (JxtV). In the control animal, the size of the constituent neurons of these five nuclei was also analyzed. The mean size of the somata was significantly (p < 0.05) different among these nuclei: it was largest in the Ta, followed by the IntV, SupV and JxtV, and smallest in the Vpr. After cerebellar and thalamic injections of WGA-HRP, labeled neurons were found in all of these nuclei. The cerebellar projection from the SupV and the thalamic projections from the Ta, SupV and IntV were observed for the first time in this study. The proportion of neurons projecting to the cerebellum and the thalamus varied in these nuclei. In the Ta and IntV, the majority of neurons were labeled after cerebellar injections, whereas nearly all neurons in the Vpr were labeled after thalamic injections. In the SupV and JxtV, thalamic projection neurons were greater in number. Thus, each nucleus examined in this study had distinct organizations concerning the soma size and the mode of projection to the cerebellum and the thalamus.
Kobayashi
Y
Y
Department of Neuroanatomy, Faculty of Medicine, University of Tokyo, Japan.
D000818:Animals; D048429:Cell Size; D002531:Cerebellum / Q000166:cytology*; D008297:Male; D009474:Neurons / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D013788:Thalamus / Q000166:cytology*; D014278:Trigeminal Nuclei / Q000166:cytology*