scholarly journals MRI- and histologically derived neuroanatomical atlas of the Ambystoma mexicanum (axolotl)

2020 ◽  
Author(s):  
Iván Lazcano ◽  
Abraham Cisneros-Mejorado ◽  
Luis Concha ◽  
Juan José Ortíz Retana ◽  
Eduardo A. Garza-Villarreal ◽  
...  
Keyword(s):  
Ambystoma Mexicanum ◽  
Brain Atlas ◽  
Future Research ◽  
Brain Anatomy ◽  
Vertebrate Model ◽  
Left And Right ◽  
Brain And Spinal Cord ◽  
The Brain ◽  
Recent Sequencing

AbstractAmphibians are an important vertebrate model system to understand anatomy, genetics and physiology. Importantly, the brain and spinal cord of adult urodels (salamanders) have an incredible regeneration capacity, contrary to anurans (frogs) and the rest of adult vertebrates. Among these amphibians, the axolotl (Ambystoma mexicanum) has gained most attention because of the surge in the understanding of CNS regeneration and the recent sequencing of its whole genome. However, a complete comprehension of the brain anatomy is not available. In the present study we created a magnetic resonance imaging atlas of the in vivo neuroanatomy of the juvenile axolotl brain. This is the first MRI atlas for this species and includes 3 levels: 1) 80 regions of interest (ROIs); 2) a division of the brain according to the embryological origin of the neural tube, and 3) left and right hemispheres. Additionally, we localized the myelin rich regions of the juvenile brain. The atlas, the template that the atlas was derived from, and a masking file, can be found on Zenodo at DOI: 10.5281/zenodo.4311937. This MRI brain atlas aims to be an important tool for future research of the axolotl brain and that of other amphibians.

scholarly journals MRI- and histologically derived neuroanatomical atlas of the Ambystoma mexicanum (axolotl)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ivan Lazcano ◽  
Abraham Cisneros-Mejorado ◽  
Luis Concha ◽  
Juan José Ortiz-Retana ◽  
Eduardo A. Garza-Villarreal ◽  
...  
Keyword(s):  
Ambystoma Mexicanum ◽  
Brain Atlas ◽  
Future Research ◽  
Brain Anatomy ◽  
Vertebrate Model ◽  
Magnetic Resonance Imaging Mri ◽  
Brain And Spinal Cord ◽  
The Brain ◽  
Recent Sequencing

AbstractAmphibians are an important vertebrate model system to understand anatomy, genetics and physiology. Importantly, the brain and spinal cord of adult urodels (salamanders) have an incredible regeneration capacity, contrary to anurans (frogs) and the rest of adult vertebrates. Among these amphibians, the axolotl (Ambystoma mexicanum) has gained most attention because of the surge in the understanding of central nervous system (CNS) regeneration and the recent sequencing of its whole genome. However, a complete comprehension of the brain anatomy is not available. In the present study we created a magnetic resonance imaging (MRI) atlas of the in vivo neuroanatomy of the juvenile axolotl brain. This is the first MRI atlas for this species and includes three levels: (1) 82 regions of interest (ROIs) and a version with 64 ROIs; (2) a division of the brain according to the embryological origin of the neural tube, and (3) left and right hemispheres. Additionally, we localized the myelin rich regions of the juvenile brain. The atlas, the template that the atlas was derived from, and a masking file, can be found on Zenodo at 10.5281/zenodo.4595016. This MRI brain atlas aims to be an important tool for future research of the axolotl brain and that of other amphibians.

scholarly journals Recapitulate development to promote axonal regeneration: good or bad approach?

2006 ◽  
Vol 361 (1473) ◽  
pp. 1565-1574 ◽  
Author(s):  
Marie T Filbin
Keyword(s):  
Spinal Cord ◽  
Axonal Regeneration ◽  
Molecular Level ◽  
Signal Transduction Pathway ◽  
Developmental Changes ◽  
Transduction Pathway ◽  
The Past ◽  
Brain And Spinal Cord ◽  
The Brain

In the past decade there has been an explosion in our understanding, at the molecular level, of why axons in the adult, mammalian central nervous system (CNS) do not spontaneously regenerate while their younger counterparts do. Now a number of inhibitors of axonal regeneration have been described, some of the receptors they interact with to transduce the inhibitory signal are known, as are some of the steps in the signal transduction pathway that is responsible for inhibition. In addition, developmental changes in the environment and in the neurons themselves are also now better understood. This knowledge in turn reveals novel, putative sites for drug development and therapeutic intervention after injury to the brain and spinal cord. The challenge now is to determine which of these putative treatments are the most effective and if they would be better applied in combination rather than alone. In this review I will summarize what we have learnt about these molecules and how they signal. Importantly, I will also describe approches that have been shown to block inhibitors and encourage regeneration in vivo . I will also speculate on what the differences are between the neonatal and adult CNS that allow the former to regenerate and the latter not to.

Imaging

2017 ◽  
Author(s):  
Robert Laureno
Keyword(s):  
Resonance Imaging ◽  
Cross Sectional ◽  
Advantages And Disadvantages ◽  
Mri Scans ◽  
Cross Sectional Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
Cellular Pathology ◽  
Brain And Spinal Cord ◽  
The Brain

This chapter on “Imaging” examines the relative advantages and disadvantages of computed tomography (CT) and magnetic resonance imaging (MRI) scans. It compares the modalities to each other and to gross neuropathology. For several decades, neurologists have been able to view cross-sectional images of living patients. Analogous to gross neuropathology, cross-sectional imaging displays the brain as an entire organ but does not demonstrate microscopic tissue or cellular pathology. By allowing practitioners to view sections of brain and spinal cord in vivo, imaging has improved neurologic practice and facilitated clinical research. This chapter deals with imaging topics that are important to the neurologist. The timing of scans, the effects of gravity, and the importance of plane of section are considered. Imaging is compared to gross neuropathology, and MRI is compared to CT.

scholarly journals Adenosine A2AReceptors in Substance Use Disorders: A Focus on Cocaine

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1372 ◽  
Author(s):  
Karolina Wydra ◽  
Dawid Gawliński ◽  
Kinga Gawlińska ◽  
Małgorzata Frankowska ◽  
Dasiel O. Borroto-Escuela ◽  
...  
Keyword(s):  
Substance Use ◽  
Substance Use Disorders ◽  
Current Knowledge ◽  
Ex Vivo ◽  
D2 Receptors ◽  
Future Research ◽  
Receptor Complexes ◽  
Abused Drugs ◽  
The Brain

Several psychoactive drugs can evoke substance use disorders (SUD) in humans and animals, and these include psychostimulants, opioids, cannabinoids (CB), nicotine, and alcohol. The etiology, mechanistic processes, and the therapeutic options to deal with SUD are not well understood. The common feature of all abused drugs is that they increase dopamine (DA) neurotransmission within the mesocorticolimbic circuitry of the brain followed by the activation of DA receptors. D2 receptors were proposed as important molecular targets for SUD. The findings showed that D2 receptors formed heteromeric complexes with other GPCRs, which forced the addiction research area in new directions. In this review, we updated the view on the brain D2 receptor complexes with adenosine (A)2A receptors (A2AR) and discussed the role of A2AR in different aspects of addiction phenotypes in laboratory animal procedures that permit the highly complex syndrome of human drug addiction. We presented the current knowledge on the neurochemical in vivo and ex vivo mechanisms related to cocaine use disorder (CUD) and discussed future research directions for A2AR heteromeric complexes in SUD.

scholarly journals Effects of Red Ginseng on Neural Injuries with Reference to the Molecular Mechanisms

J ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 116-127
Author(s):  
Pengxiang Zhu ◽  
Masahiro Sakanaka
Keyword(s):  
Molecular Mechanisms ◽  
Bioactive Molecules ◽  
Red Ginseng ◽  
Promising Candidate ◽  
Neuroprotective Effects ◽  
Chemical Structures ◽  
Brain And Spinal Cord ◽  
The Brain

Red ginseng, as an effective herbal medicine, has been traditionally and empirically used for the treatment of neuronal diseases. Many studies suggest that red ginseng and its ingredients protect the brain and spinal cord from neural injuries such as ischemia, trauma, and neurodegeneration. This review focuses on the molecular mechanisms underlying the neuroprotective effects of red ginseng and its ingredients. Ginsenoside Rb1 and other ginsenosides are regarded as the active ingredients of red ginseng; the anti-apoptotic, anti-inflammatory, and anti-oxidative actions of ginsenosides, together with a series of bioactive molecules relevant to the above actions, appear to account for the neuroprotective effects in vivo and/or in vitro. Moreover, in this review, the possibility is raised that more effective or stable neuroprotective derivatives based on the chemical structures of ginsenosides could be developed. Although further studies, including clinical trials, are necessary to confirm the pharmacological properties of red ginseng and its ingredients, red ginseng and its ingredients could be promising candidate drugs for the treatment of neural injuries.

Neurophysiology of Lampreys

1980 ◽  
Vol 37 (11) ◽  
pp. 1723-1738 ◽  
Author(s):  
Carl M. Rovainen
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Neural Control ◽  
Sensory Stimulation ◽  
Future Research ◽  
Spinal Motoneurons ◽  
Dorsal Cells ◽  
Considerable Detail ◽  
Brain And Spinal Cord ◽  
The Brain

The nervous system of the lamprey has been appreciated by comparative neuroanatomists for nearly a century as a "prototype" for the brain and spinal cord of higher vertebrates. Only recently have neurophysiologists discovered the practical advantages of the lamprey brain and spinal cord, such as relative simplicity, survival in isolation, and the occurrence of large, visible, nerve cells and axons. During the past 15 yr rapid progress has been made in understanding the basic physiological, pharmacological, and ultrastructural properties of lamprey neurons and the organization of sensory and motor systems. Several types of neurons are now known in considerable detail and include the prominent Müller and Mauthner cells, respiratory and spinal motoneurons, giant interneurons, and sensory dorsal cells. Some of the important subjects for future research include the behavioral responses of adult lampreys to different modes of sensory stimulation, the neural control of feeding, and the changes which occur in the nervous system during metamorphosis.Key words: brain, lamprey, neurophysiology, respiration, spinal cord, swimming

scholarly journals Non-parametric MRI Brain Atlas for the Polish Population

2021 ◽  
Vol 15 ◽  
Author(s):  
Damian Borys ◽  
Marek Kijonka ◽  
Krzysztof Psiuk-Maksymowicz ◽  
Kamil Gorczewski ◽  
Lukasz Zarudzki ◽  
...  
Keyword(s):  
Skewed Distribution ◽  
Brain Atlas ◽  
Brain Morphology ◽  
Rank Test ◽  
Healthy Population ◽  
Gaussian Shape ◽  
Mri Brain ◽  
The Brain ◽  
Non Parametric

Introduction: The application of magnetic resonance imaging (MRI) to acquire detailed descriptions of the brain morphology in vivo is a driving force in brain mapping research. Most atlases are based on parametric statistics, however, the empirical results indicate that the population brain tissue distributions do not exhibit exactly a Gaussian shape. Our aim was to verify the population voxel-wise distribution of three main tissue classes: gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF), and to construct the brain templates for the Polish (Upper Silesian) healthy population with the associated non-parametric tissue probability maps (TPMs) taking into account the sex and age influence.Material and Methods: The voxel-wise distributions of these tissues were analyzed using the Shapiro-Wilk test. The non-parametric atlases were generated from 96 brains of the ethnically homogeneous, neurologically healthy, and radiologically verified group examined in a 3-Tesla MRI system. The standard parametric tissue proportion maps were also calculated for the sake of comparison. The maps were compared using the Wilcoxon signed-rank test and Kolmogorov-Smirnov test. The volumetric results segmented with the parametric and non-parametric templates were also analyzed.Results: The results confirmed that in each brain structure (regardless of the studied sub-population) the data distribution is skewed and apparently not Gaussian. The determined non-parametric and parametric templates were statistically compared, and significant differences were found between the maps obtained using both measures (the maps of GM, WM, and CSF). The impacts of applying the parametric and non-parametric TPMs on the segmentation process were also compared. The GM volumes are significantly greater when using the non-parametric atlas in the segmentation procedure, while the CSF volumes are smaller.Discussion and Conclusion: To determine the population atlases the parametric measures are uncritically and widely used. However, our findings suggest that the mean and parametric measures of such skewed distribution may not be the most appropriate summary statistic to find the best spatial representations of the structures in a standard space. The non-parametric methodology is more relevant and universal than the parametric approach in constructing the MRI brain atlases.

scholarly journals l-Isoaspartyl Methyltransferase Deficiency in Zebrafish Leads to Impaired Calcium Signaling in the Brain

2021 ◽  
Vol 11 ◽  
Author(s):  
Remon Soliman ◽  
Maria Lorena Cordero-Maldonado ◽  
Teresa G. Martins ◽  
Mahsa Moein ◽  
Jean-François Conrotte ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Loss Of Function ◽  
Ht22 Cells ◽  
Homologous Genes ◽  
Vertebrate Model ◽  
And Function ◽  
First Time ◽  
The Brain ◽  
Isoaspartyl Methyltransferase

Isomerization of l-aspartyl and l-asparaginyl residues to l-isoaspartyl residues is one type of protein damage that can occur under physiological conditions and leads to conformational changes, loss of function, and enhanced protein degradation. Protein l-isoaspartyl methyltransferase (PCMT) is a repair enzyme whose action initiates the reconversion of abnormal l-isoaspartyl residues to normal l-aspartyl residues in proteins. Many lines of evidence support a crucial role for PCMT in the brain, but the mechanisms involved remain poorly understood. Here, we investigated PCMT activity and function in zebrafish, a vertebrate model that is particularly well-suited to analyze brain function using a variety of techniques. We characterized the expression products of the zebrafish PCMT homologous genes pcmt and pcmtl. Both zebrafish proteins showed a robust l-isoaspartyl methyltransferase activity and highest mRNA transcript levels were found in brain and testes. Zebrafish morphant larvae with a knockdown in both the pcmt and pcmtl genes showed pronounced morphological abnormalities, decreased survival, and increased isoaspartyl levels. Interestingly, we identified a profound perturbation of brain calcium homeostasis in these morphants. An abnormal calcium response upon ATP stimulation was also observed in mouse hippocampal HT22 cells knocked out for Pcmt1. This work shows that zebrafish is a promising model to unravel further facets of PCMT function and demonstrates, for the first time in vivo, that PCMT plays a pivotal role in the regulation of calcium fluxes.

scholarly journals Dystroglycan is a scaffold for extracellular axon guidance decisions

2018 ◽  
Author(s):  
L. Bailey Lindenmaier ◽  
Nicolas Parmentier ◽  
Caying Guo ◽  
Fadel Tissir ◽  
Kevin M Wright
Keyword(s):  
Axon Guidance ◽  
Matrix Proteins ◽  
Environmental Cues ◽  
Transmembrane Receptors ◽  
Binding Partner ◽  
Transmembrane Glycoprotein ◽  
Extracellular Signaling ◽  
Brain And Spinal Cord ◽  
The Brain

SummaryAxon guidance requires interactions between extracellular signaling molecules and transmembrane receptors, but how appropriate context-dependent decisions are coordinated outside the cell remains unclear. Here we show that the transmembrane glycoprotein Dystroglycan interacts with a changing set of environmental cues that regulate the trajectories of extending axons throughout the brain and spinal cord. Dystroglycan operates primarily as an extracellular scaffold during axon guidance, as it functions non-cell autonomously and does not require signaling through its intracellular domain. We identify the transmembrane receptor Celsr3/Adgrc3 as a binding partner for Dystroglycan, and show that this interaction is critical for specific axon guidance events in vivo. These findings establish Dystroglycan as a multifunctional scaffold that coordinates extracellular matrix proteins, secreted cues, and transmembrane receptors to regulate axon guidance.

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