Morphological and Quantitative Study of Neurons in the Gracile Nucleus of the Camel Brain Stem

Abstract

Neurons in the gracile nucleus of the camel brain stem were studied by Golgi method. Neurons were classified based on soma size and shape, density of dendritic tree, morphology and distribution of appendages. Six types of neurons were identified. Type I neurons had very large somata with appendages on their somata and distal dendrites. Type II neurons had large somata and almost smooth dendrites. Type III neurons displayed medium size somata with dendritic appendages of different forms. Type IV neurons were small to medium spheroidal or triangular neurons. Somata and dendrites of these neurons had appendages of different forms. Type V medium-size neurons had bipolar, round or fusiform somata and poorly branching dendritic tree. Some spines and appendages were seen on somata and dendrites of these neurons. Neurons of type VI were medium-size unipolar, round or fusiform with spines on their dendrites. The radiating branching pattern was more common than the tufted for all types of neurons. Wide overlap between widths of dendrites of different orders was found for all neuronal types. Hopefully, this study will improve our understanding of the role of the gracile nucleus as major center for sensory information processing and contribute to our understanding of comparative neuroanatomy and neurophysiology.