The vast majority of cortical GABAergic neurons can be defined by parvalbumin, somatostatin or calretinin expression. In most mammalians parvalbumin and somatostatin interneurons have constant proportions, each representing 5-7% of the total neuron number. In contrast, there is a 3 fold increase in the proportion of calretinin interneurons, which do not exceed 4% in rodents and reach 12% in higher order areas of primate cerebral cortex. In rodents almost all parvalbumin and somatostatin interneurons originate from the medial part of the subpallial proliferative structure, the ganglionic eminence (GE), while almost all calretinin interneurons originate from its caudal part. The spatial pattern of cortical GABAergic neurons origin from the GE is preserved in the monkey and human brain. However, it could be expected that the evolution is changing developmental rules to enable considerable expansion of calretinin interneuron population. During the early fetal period in primates cortical GABAergic neurons are almost entirely generated in the subpallium, as in rodents. Already at that time the primate caudal ganglionic eminence (CGE) shows a relative increase in size and production of calretinin interneurons. During the second trimester of gestation, that is the main neurogenetic stage in primates without clear correlates found in rodents, the pallial production of cortical GABAergic neurons together with the extended persistence of the GE is observed. We propose that the CGE could be the main source of calretinin interneurons for the posterior and lateral cortical regions, but not for the frontal cortex. The associative granular frontal cortex represents around one third of the cortical surface and contains almost half of cortical calretinin interneurons. The majority of calretinin interneurons destined for the frontal cortex could be generated in the pallium, especially in the newly evolved outer subventricular zone that becomes the main pool of cortical progenitors.

In this study we have provided a detailed quantitative morphological analysis of medium spiny neurons in the mice dorsal striatum and determined the consistency of values among three groups of animals obtained in different set of experiments. Dendritic trees of 162 Golgi Cox (FD RapidGolgiStainKit) impregnated medium spiny neurons from 15 adult C57BL/6 mice were 3-dimensionally reconstructed using Neurolucida software, and parameters of dendritic morphology have been compared among experimental groups. The parameters of length and branching pattern did not show statistically significant difference and were highly consistent among groups. The average neuronal soma surface was between 160-180 µm2, and the cells had 5-6 primary dendrites with close to 40 segments per neuron. Sholl analysis confirmed regular pattern of dendritic branching. The total length of dendrites was around 2100 µm with the average length of individual branching (intermediate) segment around 22 µm and for the terminal segment around 100 µm. Even though each experimental group underwent the same strictly defined protocol in tissue preparation and Golgi staining, we found inconsistency in dendritic volume and soma surface. These changes could be methodologically influenced during the Golgi procedure, although without affecting the dendritic length and tree complexity. Since the neuronal activity affects the dendritic thickness, it could not be excluded that observed volume inconsistency was related with functional states of neurons prior to animal sacrifice. Comprehensive analyses of tree complexity and dendritic length provided here could serve as an additional tool for understanding morphological variability in the most numerous neuronal population of the striatum. As reference values they could provide basic ground for comparisons with the results obtained in studies that use various models of genetically modified mice in explaining different pathological conditions that involve medium spiny neurons.

To analyze axon morphology on rapid Golgi impregnated pyramidal neurons in the dorsolateral prefrontal cortex in schizophrenia.Postmortem brain tissue from five subjects diagnosed with schizophrenia and five control subjects without neuropathological ...

Medical education has undergone a significant reform in response to evolving healthcare demands, technological advancements, and emerging research in biomedical and education sciences. The teaching methods in anatomy, a core component of medical ...