Spindle-Shaped Neurons in the Human Posteromedial (Precuneus) Cortex

The human posteromedial cortex (PMC), which includes the precuneus (PC), represents a multimodal brain area implicated in emotion, conscious awareness, spatial cognition, and social behavior. Here, we describe the presence of Nissl-stained elongated spindle-shaped neurons (suggestive of von Economo neurons, VENs) in the cortical layer V of the anterior and central PC of adult humans. The adapted “single-section” Golgi method for postmortem tissue was used to study these neurons close to pyramidal ones in layer V until merging with layer VI polymorphic cells. From three-dimensional (3D) reconstructed images, we describe the cell body, two main longitudinally oriented ascending and descending dendrites as well as the occurrence of spines from proximal to distal segments. The primary dendritic shafts give rise to thin collateral branches with a radial orientation, and pleomorphic spines were observed with a sparse to moderate density along the dendritic length. Other spindle-shaped cells were observed with straight dendritic shafts and rare branches or with an axon emerging from the soma. We discuss the morphology of these cells and those considered VENs in cortical areas forming integrated brain networks for higher-order activities. The presence of spindle-shaped neurons and the current discussion on the morphology of putative VENs address the need for an in-depth neurochemical and transcriptomic characterization of the PC cytoarchitecture. These findings would include these spindle-shaped cells in the synaptic and information processing by the default mode network and for general intelligence in healthy individuals and in neuropsychiatric disorders involving the PC in the context of the PMC functioning.

A GLP-1/GIP Dual Receptor Agonist DA4-JC Effectively Attenuates Cognitive Impairment and Pathology in the APP/PS1/Tau Model of Alzheimer’s Disease

Background: Alzheimer’s disease (AD) is a degenerative disorder, accompanied by progressive cognitive decline, for which there is no cure. Recently, the close correlation between AD and type 2 diabetes mellitus (T2DM) has been noted, and a promising anti-AD strategy is the use of anti-T2DM drugs. Objective: To investigate if the novel glucagon-like peptide-1 (GLP-1)/glucose-dependent insulinotropic polypeptide (GIP) receptor agonist DA4-JC shows protective effects in the triple APP/PS1/tau mouse model of AD. Methods: A battery of behavioral tests were followed by in vivo recording of long-term potentiation (LTP) in the hippocampus, quantified synapses using the Golgi method, and biochemical analysis of biomarkers. Results: DA4-JC improved cognitive impairment in a range of tests and relieved pathological features of APP/PS1/tau mice, enhanced LTP in the hippocampus, increased numbers of synapses and dendritic spines, upregulating levels of post-synaptic density protein 95 (PSD95) and synaptophysin (SYP), normalized volume and numbers of mitochondria and improving the phosphatase and tensin homologue induced putative kinase 1 (PINK1) - Parkin mitophagy signaling pathway, while downregulating amyloid, p-tau, and autophagy marker P62 levels. Conclusion: DA4-JC is a promising drug for the treatment of AD.

The doctrine of neurons before the court of the newest researchers

The modern doctrine of neurons penetrated very quickly into the scientific consciousness of neurologists because of the clarity and definiteness of the basic provisions that clarify the pathways and methods of transmitting irritation in the nervous system. Based mainly on the Golgi method, it was, however, also consistent with the facts obtained using the methods of Gooden, Fleksig, Weigert, Marka as far as they concerned the course of nerve bundles; but the Golgi method had the advantage over the previous methods that it clarified the relationship of the nerve fiber to the cell and made it possible to follow the course and development of a particular fiber. In addition, the main provisions of this study were consistent with the development of nervous cells according to the research of Giss, with experimental physiology and clinical medicine, as well as with experimental pathology.

S. Sukhanov. The pathological anatomy of the nerve cell in relation to varicose atrophy of the dendrites of the cerebral cortex. Extract from the Journal "La Cellule" t. XIV, 2nd fascicle

In this article, the author has applied the Golgi method for studying changes in the cells of the cerebral cortex in case of poisoning with arsenic, in case of infection with canine rabies, in case of poisoning with teberculin and in thyroidectomy.

S. Sukhanov. Contribution to the study of changes undergone by dendritic extensions of nerve cells under the influence of narcotics. Extract from the Journal “la Cellule” t. XIV, 2nd fascicle

The author exposed different animals to the action of ether, chloroform, alcohol and trional, and then studied the cortex of the dead from the action of these animal substances using the Golgi method.

H. M. Reznikov. To the doctrine of the structure of the retina. -Diss. SPb. 1897 year

The work was carried out in the laboratory arranged by the author at the zemstvo emergency room. The author made his research according to the Golgi-Cajal method. At the beginning of the work, the author gives a short historical overview of the study of the structure of the retina, then describes the technique of the Golgi method in applying to the retina and finally gives the results of his own studies on birds. The author's conclusions are as follows: In day birds, the position of the nuclei in the outer nuclear, the layer is fixed only at the rods (near the outer border of the outer gossip-like layer). The cone nuclei lie in this layer at different heights. In night birds, cones and rods have the same base of legs and the same exact arrangement of nuclei as in mammals; fixed nuclei (at the inner border of m. limitans externa) have only cones. And so, the visual cells in night and day birds represent an inverse relationship in the sense of the position and fixation of the nuclei.

The Recent Advancement in Rapid Golgi Method and Result Interpretation

The foundation knowledge of recent advancements of neuroscience was based on the Golgi staining observations. This is one of the best approaches to visualise the neuronal cytoarchitecture and complete morphology of neurons with incomparable clarity. This technique is based on the principle of heavy metal impregnation. There are many modifications and advancement occurred to improve the visualization. This chapter will provide the recently used protocols to visuals the neuronal architecture, dendritic arborization and spine density in different brain regions. Along with the manual observation, the present chapter also describes the currently used tools and software for the better understanding and visualisation of neurons.

Endothelial cells filopodia participation in the anastomosis of CNS capillaries

By combining the classic Golgi method and the electron microscope, we have gained a better understanding of the anastomosis of CNS blood capillaries. The participation of growing capillary’ leading endothelial cells filopodia in the anastomotic process is described. The two approaching capillaries leading endothelial cells filopodia intermingle and interact forming complex conglomerates with narrow spaces filled with proteinaceous material (possibly basal lamina) secreted by them. The presence of tight junctions among the filopodia corroborates their vascular nature. Their presence also suggests a different endothelial cells origin as will those from the two approaching capillaries. The original narrow spaces coalesce into larger ones leading to the eventual formation of a single one that will interconnect (anastomose) the two capillaries. The newly formed post-anastomotic CNS capillaries are rather small with irregular and narrow lumina that might permit the passage of fluid but not yet of blood cells. Eventually, the new capillaries lumina will enlarge permitting the passage of blood cells.Funding informationThe M. M-P. Golgi studies were supported by a “Jacob Javits Neurosciences Investigator Award". NIH Grant NS-22897. And the L. H. EM studies were supported by the Gilman Fund/Class of 1978 Life Sciences Center. M. M-P. is Emeritus Professor of Pathology and Pediatrics and L. H. is a Consulting Electron Microscopists. Both from the Geisel School of Medicine at Dartmouth. Hanover, NH 03755, USA

The renaissance of the neuron doctrine: Cajal rebuts the Rector of Granada

The Spanish histologist Santiago Ramón y Cajal and the Italian anatomist Camillo Golgi, who were jointly awarded the 1906 Nobel Prize in Physiology or Medicine for their discoveries on the structure of the nervous system, are two of the most notable figures in neuroscience. It was the’ Golgi method’ that enabled Cajal to gather evidence and defend neuronism (the contiguity of neurons as independent cellular units) against his chief rival’s reticularism (the intracellular continuity of the cytoplasm among neurons in a widespread reticulum). Seven months after his Nobel lecture in Stockholm, Cajal wrote a powerful article which he titled’ El renacimiento de la doctrina neuronal’ (the rebirth, revival, or renaissance of the neuron doctrine) as a response to an insurrection of reticularist ideas. This new wave of reticularism was instigated in Spain by the pathologist Eduardo García Solá, Rector of the University of Granada at the time, and stemmed from the interpretation of nerve regeneration experiments conducted by the German physiologist Albrecht von Bethe in Strassburg (today Strasbourg, France) and the Hungarian histologist Stephan von Apáthy in Kolozsvár (today Cluj-Napoca, Romania). Cajal’s article was hosted by four different journals (three in Spain and one in Argentina). It constitutes an important testimony for the history of the neuron theory that has gone unheeded thus far. Therefore, we provide an English translation of Cajal’s Spanish paper, placing it in the context of evolving notions during that first decade of the twentieth century crucial for neurobiology.