in the series of publications, which this article opens, we consider five fundamental neuromorphological observations of our compatriot, the classic of world neuroscience, Volodymr Betz. For four of them, we demonstrate the status of discoveries for the first time, for the other one — the giant pyramidal neurons of the motor cortex — despite its widespread and long-standing recognition, we reveal the limitations of modern knowledge and ideas. Two of the mentioned observations — giant fusiform, or spindle-shaped neurons of the cingulate and insular cortex and islands of the entorhinal cortex — are currently known only to a narrow circle of specialists; to the others two, islands of Calleja and signs of the columnar cortex organization, we pay attention for the first time. In this, the initial part of the series, exposing modern apprehensions about the structure and functions of the entorhinal cortex, we demonstrate the weight of Betz's pioneering observation of extraordinary neuron clusters, which are nowadays known as entorhinal islands, and prove the fact of recognizing his historical priority in the description of these amazing brain structures.

Purpose: to evaluate changes in the structure of synaptic contacts in various types of focal brain pathology. Materials and methods. The results of treatment of 40 cases of supratentorial focal lesions of the brain (FLB) were retrospectively evaluated. The cases are divided into groups: 30 gliomas of various degrees of malignancy and 5 consequences of TBI, 5 epilepsy. All patients underwent surgical interventions. The synaptic plasticity of axo-dendritic and axo-spiny asymmetric synapses of neurons of the VI-VII layers of the frontotemporal cortex was studied by electron microscopy. Morphometric analysis was carried out on a computer image analyzer САИ-01АВН using the software "Kappa opto-electronics GmbH" using the STATISTICA 7 program package. The results. It was established that the density of synapses decreased in glioblastomas (GB) and craniocerebral injury (ССІ). Qualitative changes demonstrate the plasticity of architectonics of synapse, in particular due to the increase in the number of perforated synaptic contacts. Maximum thickening and diffuse stratification of the postsynaptic seal indicates a violation of the functional capacity of the postsynaptic component of the contacts. A decrease in the number of synaptic vesicles was revealed in ССІ and GB, with their rearrangement, which is probably a manifestation of synaptic dysfunction. The latter proves the irreversibility of destructive local changes and is unfavorable criterion. The risk of the formation of destructive-degenerative changes in the synaptic apparatus is 7.64 times higher in DA, 3.17 times higher in GB, and 17.31 times higher in ССІ compared to cases of epilepsy, with GB significantly increases by 13.5 times compared to DA. Therefore, the assessment of the structural features of neuroplasticity should take into account the morphogenesis of the BM in comparison with clinical data Conclusions. In the zones of invasive growth of gliomas of various degrees of malignancy and in ССІ and epilepsy, the indicators of synaptic plasticity differ statistically significantly. The density of placement of synapses is lower in GB and ССІ. The probability of non-reversibility of destructive-degenerative changes of synapses according to the number of SVs in FLB correlates with the degree of glioma differentiation with a sensitivity of 81.0% and a specificity of 76.0%. According to the structural changes of synaptic connections in tumors, probable differences between the variants have been proven: GB and DA, the sensitivity of the discriminant model is 85.0%, the specificity is 74.0%, which is an indirect evidence of the growth rate of the tumor mass and its destructive effect on the surrounding brain matter. The obtained results are important in assessing the prognosis of the further course of the disease.

Corrections to the article: https://doi.org/10.25305/unj.234154 In the article by V.V. Medvedev et al., published in UNJ № 3 in 2021, the source number 92 from the reference list does not support the statement given in the appropriate place in the text. Instead, we offer the reader two other works that mention the presence of posterior median spinal artery in the adult rat - D. Mazensky et al. (2017) and O.U. Scremin (G. Paxinos, ed.; 2015, p. 1003, 1005). In most works on this topic (Z. Zhang et al., 2001; Y. Cao et al., 2015; P. Li et al., 2020) the dorsal median vein is considered as the median vessel of the posterior surface of the rat spinal cord, and as in humans, describe 2 parallel dorsal spinal arteries. At the same time, D. Mazensky et al. (2017), sharing the opinion of O.U. Scremin (2015), mention 3 dorsal spinal arteries of the rat, in particular the median one. Taking into account that, from our experience, damage to the median vessel of the posterior surface of the spinal cord is accompanied by its rapid edema and irrepversible deep deficit in the motor function of both hind limbs of the animal, we consider it necessary to draw the reader's attention to this feature of the anatomy of the spinal arteries of an adult rat. Medvediev VV, Abdallah IM, Draguntsova NG, Savosko SI, Vaslovych  VV, Tsymbaliuk VI, Voitenko NV. [Model of spinal cord lateral hemi-excision at the lower thoracic level for the tasks of reconstructive and experimental neurosurgery]. Ukr Neurosurg J [Internet]. 2021 Sep 27 [cited 2021 Oct 11];27(3):33-5. Available from: http://theunj.org/article/view/234154 Cao Y, Wu T, Yuan Z, Li D, Ni S, Hu J, Lu H. Three-dimensional imaging of microvasculature in the rat spinal cord following injury. Sci Rep. 2015 Jul 29;5:12643. doi: 10.1038/srep12643. PMID: 26220842; PMCID: PMC4518284. Li P, Xu Y, Cao Y, Wu T. 3D Digital Anatomic Angioarchitecture of the Rat Spinal Cord: A Synchrotron Radiation Micro-CT Study. Front Neuroanat. 2020 Jul 22;14:41. doi: 10.3389/fnana.2020.00041. PMID: 32792915; PMCID: PMC7387706. Mazensky D, Flesarova S, Sulla I. Arterial Blood Supply to the Spinal Cord in Animal Models of Spinal Cord Injury. A Review. Anat Rec (Hoboken). 2017 Dec;300(12):2091-2106. doi: 10.1002/ar.23694. Epub 2017 Oct 13. PMID: 28972696. Paxinos G, editor. The rat nervous system. 4th ed., London: Elsevier; 2015. Scremin OU. Capter 31, Cerebral Vascular System; p. 985‒1011. Zhang Z, Nonaka H, Nagayama T, Hatori T, Ihara F, Zhang L, Akima M. Circulatory disturbance of rat spinal cord induced by occluding ligation of the dorsal spinal vein. Acta Neuropathol. 2001 Oct;102(4):335-8. doi: 10.1007/s004010100377. PMID: 11603808.