Neurons in the Caudate Nucleus of the Camel and Human: A Comparative Study

Abstract

The caudate nucleus is described as a huge, subcortical grey mass in the forebrain known for its role in motor function and involved in a number of clinical syndromes. During ontogenesis, the caudate nucleus follows the curvature of the telencephalic vesicle, hence its curved shape. Its rostral portion referred to as the head, is far more voluminous than the body.AimsThis study aimed to describe the different types and characteristics of neurons in the caudate nucleus of the brain of camel and human and compare these neurons with their counterparts in other species.Method4mm thick blocks containing caudate nucleus was cut, dry and processed according to the rapid Golgi and or the Golgi‐Kopsch methods (double impregnation). Well‐impregnated neurons studied under light microscope.ResultsAccording to the present study, neurons were classified according to the density and distribution of the spines along their axons and dendrites. Neurons in this study classified into three main types in the caudate nucleus of camel and human. According to the somal size each group includes one or more of the following cell size: large, medium and small. Rich‐spiny neurons (Type I): include medium and small subtypes. Hairy‐like, mushroom‐like and stubby spines were present in the secondary dendrite and their branching. Sparsely‐spiny neurons (Type II): they have relatively larger cell bodies and thicker primary dendrites than (Type I). Characterized by their very low density of spines and poorer branching of their dendrites. Aspiny‐neurons (Type III): are large, medium and small size. May have varicose, appendages with various types and short axon which gives collaterals mostly within the dendritic domain.ConclusionThe neuronal structure of the caudate nucleus in the camel is differ from that of the human. The human neurons appear slightly larger than those of the camel and they have more dendritic trunks that break up more often than the neurons of the camel. Although the types of spines are similar in both species, the density of spines appears to be greater in the camel than in the human. The structural differences of the caudate neurons between two species may result from the fact that the homo sapeneis belongs to a phylogenetically younger order (Anthropoidea) than the camel. (Artiodactyla) which support the fact that the number and diversity of the types of neurons go to increase throughout phylogenesis.