Recent morphological data on human brain development are quite fragmentary. However, they are highly requested for a number of medical practices, educational programs, and fundamental research in the fields of embryology, cytology and histology, neurology, physiology, path anatomy, neonatology, and others. This paper provides the initial information on the new online Human Prenatal Brain Development Atlas (HBDA). The Atlas will start with forebrain annotated hemisphere maps, based on human fetal brain serial sections at the different stages of prenatal ontogenesis. Spatiotemporal changes in the regional-specific immunophenotype profiles will also be demonstrated on virtual serial sections. The HBDA can serve as a reference database for the neurological research, which provides opportunity to compare the data obtained by noninvasive techniques, such as neurosonography, X-ray computed tomography and magnetic resonance imaging, functional magnetic resonance imaging, 3D high-resolution phase-contrast computed tomography visualization techniques, as well as spatial transcriptomics data. It could also become a database for the qualitative and quantitative analysis of individual variability in the human brain. Systemized data on the mechanisms and pathways of prenatal human glio- and neurogenesis could also contribute to the search for new therapy methods for a large spectrum of neurological pathologies, including neurodegenerative and cancer diseases. The preliminary data are now accessible on the special HBDA website.

The human neocortex has a huge surface area with unique cytoarchitectonics, most of which is concealed in sulci. Some cytoarchitectonic fields are associated with macroscopic landmarks. In particular, the primary visual field 17 is associated with the calcarine sulcus. During the prenatal development of the human brain, neocortical gyri and sulci undergo changes and modifications after primary formation. To explore the morphogenetic processes in visual fields during the formation of the primary (provisional) and secondary (permanent) sulci, the occipital lobe of the human fetal brain was studied using immunohistochemical methods. The distribution of various glial and neuronal markers (S-100, β-III-tubulin, NeuN, reelin) in the calcarine sulcus and parietooccipital sulcus was compared. The heterogeneity in the formation of primary and secondary visual fields was demonstrated. The study revealed that the development of the primary visual field 17, linked with the calcarine sulcus, preceded the development of a shared anlage of fields 18 and 19 linked with the parietooccipital sulcus. The functional differentiation of the primary visual field begins during the period of thalamic afferent ingrowth. This process coincides with the temporal smoothing of the calcarine sulcus, indicating a simultaneous progression of functional specialization and structural modifications. At the late fetal period, cortical plate of gyri and sulci banks showed higher NeuN-labeling than inside the sulcus in the same cytoarchitectonic field.

BACKGROUND: The development of effective treatments for diabetes mellitus directly depends on a comprehensive understanding of the mechanisms underlying endocrine cell differentiation and pancreatic islet morphogenesis. Experimental studies have demonstrated that the nervous system plays an important role in regulating these processes. In the developing human pancreas, neural structures closely interact with hormone-containing cells, forming neuroinsular complexes, as well as with epithelial cells, suggesting a potential involvement of the nervous system in pancreatic islet development. To support this hypothesis, data on interactions between neural structures and cells exhibiting a progenitor immunophenotype are essential; however, such data are currently lacking in the scientific sources. AIM: To investigate the distribution of cells expressing the transcription factor PDX1 and bihormonal cells within neuroinsular complexes during human pancreatic development. METHODS: The study was performed on autopsy specimens of the pancreas obtained from 15 human fetuses (gestational age of 9–25 weeks). Multiple immunofluorescence staining and confocal microscopy were used. To assess the cellular composition of neuroinsular complexes, various combinations of antibodies were applied: against endocrine cell hormones (insulin, glucagon, somatostatin), against the transcription factor PDX1 (pancreatic and duodenal homeobox 1), and against the neural marker neuron-specific β3-tubulin. RESULTS: Triple immunofluorescence staining with antibodies against insulin, PDX1, and β3-tubulin revealed cells with a progenitor immunophenotype characteristic of ductal epithelial cells within neuroinsular complexes: insulin−/PDX1+/β3-tubulin− and insulin−/PDX1+/β3-tubulin+ cells. Starting from the 9th week of gestation, such cells were detected in isolated ganglia, and from the 14th week onward, in ganglia integrated with pancreatic islets within neuroinsular complexes. In specimens stained with insulin/glucagon/β3-tubulin and insulin/somatostatin/β3-tubulin antibody combinations, bihormonal insulin+/glucagon+ and insulin+/somatostatin+ cells were identified within neuroinsular complexes. CONCLUSION: The present study demonstrates spatial integration of neural structures with cells exhibiting a progenitor immunophenotype and with bihormonal cells in the developing human pancreas. These bihormonal cells are regarded by most authors as endocrine cells at a stage of differentiation and maturation. Such integration may be necessary for the regulation of β-cell mass and maturation, as well as for modulation of pancreatic islet morphogenesis, as previously shown in experimental studies in animal models and cell cultures.

Introduction. Brain functioning is kept by both neuronal cell activity and macroglia, i.e., astrocytes and oligodendrocytes. The current data on the prenatal development of the human brain are scarce, and gliogenesis is less studied than cortical neurogenesis. Normal limits and variations and spatiotemporal patterns of glial differentiation in human brain development remain poorly studied. Materials and methods. We used human fetal autopsy samples from the Collection of the Laboratory of Nervous System Development of Avtsyn Research Institute of Human Morphology. For immune and morphological analysis, samples of 38 fetal cerebral hemispheres at stages from 8 postconceptional weeks to birth were chosen. Results. We provided the results of the pilot comparative immune and morphological study with the panel of markers (GFAP, ALDH1L1, FABP-7) of the fetal human telencephalon in prenatal ontogenesis. Specific differentiation and maturation of the astrocyte population on the telencephalon start before early fetal period (12–13 gestational weeks). GFAP+ and ALDH1L1+ astrocyte populations in early human telencephalon are still to be studied for their homology. Analysis of GFAP+ and ALDH1L1+ glioblast distribution proposes dorsal proliferative zone as a source for fibrous cortical astrocytes. Comparative immune and morphological analysis of FABP-7+ neuroblasts in the fetal telencephalon questions whether FABP-7 cells belong to astrocyte population at early prenatal human ontogenesis. Conclusion. In the telencephalon, temporal and/or spatiotemporal translational profiles of these three antigens differ, which indicates that the astrocyte population is heterogeneous in early ontogenesis. Keywords: human brain development, telencephalon, glial differentiation, astrocytes, astrocyte fate lineage, GFAP, ALDH1L1, FABP-7

Introduction. The formation and maturation of the cortical plate in the sulci and gyri of the human brain are incompletely understood. To evaluate the maturation pattern of the gyrified cortex, the distribution of immunohistochemical markers for synaptic activity and mature neurons in the human visual cortex was investigated during the late fetal and postnatal periods. Materials and methods. We analyzed 14 human post-mortem brain samples. The distribution of GAD65/67, GAT-1, and NeuN in sulcal and gyral regions and sulcal banks was examined using immunohistochemistry. Results. Сortical maturation proceeds in clusters, representing second-order functional neural assemblies. The cortical regions of sulcal banks and gyri mature earlier followed by maturation of the cortex within the sulci. Conclusion. The gyrified cortex exhibits asynchronous maturation with the regions at the boundaries of sulci and gyri reaching maturity earlier than sulcal regions. There is a complex interplay between gyrification and cortical maturation, indicating a strong link between the structural organization of the cortex and its functional development. Keywords: visual field, cerebral maturation, gyrification, sulci, gyri, human brain development, GAD65/67, GAT-1, NeuN

The human olfactory bulb is a promising structure for the investigation of central nervous system disorders, including dementias of various etiologies. In Alzheimer’s disease, anosmia is among the earliest clinical manifestations. Although olfactory disturbances have also been reported in schizophrenia, alterations within the olfactory system remain insufficiently studied. The aim of this study was to identify changes in the olfactory bulbs of patients with schizophrenia. Olfactory bulbs obtained from patients with schizophrenia (n = 23) and individuals without identified nervous system pathology (n = 23) were examined. Patients with schizophrenia demonstrated a statistically significant decrease in the immunoreactive area of myelin basic protein and a significant increase in the immunoreactive area of glial fibrillary acidic protein compared with the control group. In addition, the thickness of the layer of incoming olfactory nerve fibers was significantly reduced in the schizophrenia group. Overall, our findings demonstrate neuroglial alterations in the human olfactory bulb in schizophrenia. Together with observations from other brain regions, these results may indicate that the identified changes are systemic rather than localized in nature.