Neuronal Types in the Human Anterior Ventral Thalamic Nucleus: A Golgi Study

Abstract

Neurons in the anterior ventral (AV) thalamic nucleus of human adults were impregnated by Golgi-Kopsch impregnation method. Results showed that at least three morphological types of neurons could be recognized in the human AV thalamic nucleus. Type I neurons were medium to large with rich dendritic arborization. Both tufted and radiating dendritic branching patterns were seen in almost every neuron of this type. Only the initial axonal segments of these cells were impregnated suggesting that these axons were heavily myelinated. Type II neurons were medium in size with poor to moderate dendritic arborization. Many of these cells possess a few dendritic grape-like appendages. Long segments (up to 300 microm) of their axons were impregnated suggesting that these axons were either unmyelinated or thinly myelinated. These axons change their direction and form loops very often. No local branches were seen for these axons suggesting that they could be projection axons. Type III neurons were small with only one or two dendrites with poor arborization. No axons for these cells were seen in this study. The three neuronal types in the human AV thalamic nucleus were compared with neuronal types already described in other thalamic nuclei of human and non-human species. The results of this study might provide a morphological basis for further electrophysiological and / or pathological studies.

Neuronal cell types in the anterior ventral thalamic nucleus of the camel

“…Golgi-type I nerve cells found in this study were found to be generally similar to their counterparts previously described in other thalamic nuclei including the human anterior ventral, ventral anterior, ventral posterior, ventral lateral nuclei as well as medial geniculate, and lateral geniculate bodies (Al-Hussain Bani Hani et al, 2008;Braak & Braak, 1984;Grodd et al, 2020;Hajdu, Hassler, & Somogyi, 1982;Hani et al, 2007;Hazlett et al, 1976;Pearson & Haines, 1980;Schaltenbrand & Wahen, 1977;Tseng & Royce, 1986). In all these studies, Golgi-type I nerve cells were found to have medium to large cell bodies and dense dendritic trees.…”

“…In the human AV, two morphologically different types of neurons were found, one corresponded to Golgi-type I with large body and dense dendritic trees while the other type corresponded to Golgi-type II with small body, few branches and grape-like dendritic appendages. Although long segments of the axons of these small neurons were impregnated in one study (Hani et al, 2007), no local axonal branches were found. This may indicate that these neurons could be in fact thalamocortical projecting neurons rather than interneurons which come in agreement with the result of the other study (Somogyi et al, 1973).…”

“…Giving that the human brain anterior ventral thalamic nucleus (AV) was already studied in our laboratory (Al-Hussain Bani Hani, El-Dwairi, Bataineh, Al-Haidari, & Al-Alami, 2008;Hani, Al-Haidari, & Saboba, 2007); we decided to study this nucleus in the camel brain. The AV thalamic nucleus is located immediately posterior to the interventricular foramen as a thalamic tubercle.…”

“…The morphological features of neurons in various thalamic nuclei were described in many species by different studies (Al-Hussain, 1992;Al-Hussain & Kultas-Ilinsky, 1986;Braak & Braak, 1984;Braitenberg, Guglielmotti, & Sada, 1967;Fox, Ubeda-Purkiss, Ihrig, & Biagioli, 1951;Guillery, 1966;Hani et al, 2007;Kiss & Tömböl, 1972;Kuroda, López-Mascaraque, & Price, 1992;Ma, Lynch, Donahoe, Attallah, & Rafols, 1998;Morest, 1975;Pearson & Haines, 1980;Rafols, Aronin, & Difiglia, 1987;Saini & Garey, 1981;Scheibel & Scheibel, 1966;Spreafico, Schmechel, Ellis Jr, & Rustioni, 1983;Tömböl, Ungváry, Hajdu, Madarász, & Somogyi, 1969;Winer, 1984;Yamamoto, Noda, Samejima, & Oka, 1985;Yen, Conley, & Jones, 1985). In the majority of these nuclei, two main types of neurons namely Golgi-type I and Golgi-type II were found.…”

“…The same study reported that all of the neurons in the dorsomedial nucleus were large and considered as thalamocortical projection neurons. Another thalamic nucleus namely the anteroventral nucleus had been studied in both human (Hani et al, 2007) and cat (Somogyi, Tömböl, & Hajdu, 1973). In the human AV, two morphologically different types of neurons were found, one corresponded to Golgi-type I with large body and dense dendritic trees while the other type corresponded to Golgi-type II with small body, few branches and grape-like dendritic appendages.…”