scholarly journals Doublecortin-Expressing Neurons in Chinese Tree Shrew Forebrain Exhibit Mixed Rodent and Primate-Like Topographic Characteristics

2021 ◽  
Vol 15 ◽  
Author(s):  
Jia-Qi Ai ◽  
Rongcan Luo ◽  
Tian Tu ◽  
Chen Yang ◽  
Juan Jiang ◽  
...  
Keyword(s):  
Subventricular Zone ◽  
Cortical Neurons ◽  
Hippocampal Formation ◽  
Tree Shrew ◽  
Piriform Cortex ◽  
Subgranular Zone ◽  
Tree Shrews ◽  
Immature Neurons ◽  
Topographic Characteristics ◽  
The Brain

Doublecortin (DCX) is transiently expressed in new-born neurons in the subventricular zone (SVZ) and subgranular zone (SGZ) related to adult neurogenesis in the olfactory bulb (OB) and hippocampal formation. DCX immunoreactive (DCX+) immature neurons also occur in the cerebral cortex primarily over layer II and the amygdala around the paralaminar nucleus (PLN) in various mammals, with interspecies differences pointing to phylogenic variation. The tree shrews (Tupaia belangeri) are phylogenetically closer to primates than to rodents. Little is known about DCX+ neurons in the brain of this species. In the present study, we characterized DCX immunoreactivity (IR) in the forebrain of Chinese tree shrews aged from 2 months- to 6 years-old (n = 18). DCX+ cells were present in the OB, SVZ, SGZ, the piriform cortex over layer II, and the amygdala around the PLN. The numerical densities of DCX+ neurons were reduced in all above neuroanatomical regions with age, particularly dramatic in the DG in the 5–6 years-old animals. Thus, DCX+ neurons are present in the two established neurogenic sites (SVZ and SGZ) in the Chinese tree shrew as seen in other mammals. DCX+ cortical neurons in this animal exhibit a topographic pattern comparable to that in mice and rats, while these immature neurons are also present in the amygdala, concentrating around the PLN as seen in primates and some nonprimate mammals.

scholarly journals Effects of Brain Size on Adult Neurogenesis in Shrews

2021 ◽  
Vol 22 (14) ◽  
pp. 7664
Author(s):  
Katarzyna Bartkowska ◽  
Krzysztof Turlejski ◽  
Beata Tepper ◽  
Leszek Rychlik ◽  
Peter Vogel ◽  
...  
Keyword(s):  
Adult Neurogenesis ◽  
Subventricular Zone ◽  
Molecular Mechanisms ◽  
Brain Size ◽  
Hippocampal Formation ◽  
Small Animals ◽  
Suncus Murinus ◽  
The Brain ◽  
Neomys Fodiens ◽  
Migratory Stream

Shrews are small animals found in many different habitats. Like other mammals, adult neurogenesis occurs in the subventricular zone of the lateral ventricle (SVZ) and the dentate gyrus (DG) of the hippocampal formation. We asked whether the number of new generated cells in shrews depends on their brain size. We examined Crocidura russula and Neomys fodiens, weighing 10–22 g, and Crocidura olivieri and Suncus murinus that weigh three times more. We found that the density of proliferated cells in the SVZ was approximately at the same level in all species. These cells migrated from the SVZ through the rostral migratory stream to the olfactory bulb (OB). In this pathway, a low level of neurogenesis occurred in C. olivieri compared to three other species of shrews. In the DG, the rate of adult neurogenesis was regulated differently. Specifically, the lowest density of newly generated neurons was observed in C. russula, which had a substantial number of new neurons in the OB compared with C. olivieri. We suggest that the number of newly generated neurons in an adult shrew’s brain is independent of the brain size, and molecular mechanisms of neurogenesis appeared to be different in two neurogenic structures.

scholarly journals Regeneration and Plasticity in the Brain and Spinal Cord

2007 ◽  
Vol 27 (8) ◽  
pp. 1417-1430 ◽  
Author(s):  
Barbro B Johansson
Keyword(s):  
Spinal Cord ◽  
Progenitor Cells ◽  
Subventricular Zone ◽  
Cortical Neurons ◽  
Brain Plasticity ◽  
Brain Lesions ◽  
Mammalian Brain ◽  
Long Distance ◽  
Inhibitory Factors ◽  
The Brain

The concept of brain plasticity covers all the mechanisms involved in the capacity of the brain to adjust and remodel itself in response to environmental requirements, experience, skill acquisition, and new challenges including brain lesions. Advances in neuroimaging and neurophysiologic techniques have increased our knowledge of task-related changes in cortical representation areas in the intact and injured human brain. The recognition that neuronal progenitor cells proliferate and differentiate in the subventricular zone and dentate gyrus in the adult mammalian brain has raised the hope that regeneration may be possible after brain lesions. Regeneration will require that new cells differentiate, survive, and integrate into existing neural networks and that axons regenerate. To what extent this will be possible is difficult to predict. Current research explores the possibilities to modify endogenous neurogenesis and facilitate axonal regeneration using myelin inhibitory factors. After apoptotic damage in mice new cortical neurons can form long-distance connections. Progenitor cells from the subventricular zone migrate to cortical and subcortical regions after ischemic brain lesions, apparently directed by signals from the damaged region. Postmortem studies on human brains suggest that neurogenesis may be altered in degenerative diseases. Functional and anatomic data indicate that myelin inhibitory factors, cell implantation, and modification of extracellular matrix may be beneficial after spinal cord lesions. Neurophysiologic data demonstrating that new connections are functioning are needed to prove regeneration. Even if not achieving the goal, methods aimed at regeneration can be beneficial by enhancing plasticity in intact brain regions.

scholarly journals Hippocampal Neurogenesis, Depressive Disorders, and Antidepressant Therapy

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Eleni Paizanis ◽  
Michel Hamon ◽  
Laurence Lanfumey
Keyword(s):  
Subventricular Zone ◽  
Depressive Disorders ◽  
Antidepressant Drugs ◽  
Hippocampal Neurogenesis ◽  
Antidepressant Therapy ◽  
Trophic Factors ◽  
Subgranular Zone ◽  
Antidepressant Treatments ◽  
The Brain ◽  
Stimulation Of

There is a growing body of evidence that neural stem cells reside in the adult central nervous system where neurogenesis occurs throughout lifespan. Neurogenesis concerns mainly two areas in the brain: the subgranular zone of the dentate gyrus in the hippocampus and the subventricular zone, where it is controlled by several trophic factors and neuroactive molecules. Neurogenesis is involved in processes such as learning and memory and accumulating evidence implicates hippocampal neurogenesis in the physiopathology of depression. We herein review experimental and clinical data demonstrating that stress and antidepressant treatments affect neurogenesis in opposite direction in rodents. In particular, the stimulation of hippocampal neurogenesis by all types of antidepressant drugs supports the view that neuroplastic phenomena are involved in the physiopathology of depression and underlie—at least partly—antidepressant therapy.

Morphological Examination of a Herpes-type Virus Indigenous for Tree Shrews

1970 ◽  
Vol 28 ◽  
pp. 160-161
Author(s):  
J. P. Brunschwig ◽  
R. M. McCombs ◽  
R. Mirkovic ◽  
M. Benyesh-Melnick
Keyword(s):  
Electron Microscopy ◽  
Soft Tissue ◽  
Chick Embryo ◽  
Soft Tissue Sarcoma ◽  
Cell Cultures ◽  
Tree Shrew ◽  
Type Virus ◽  
Morphological Examination ◽  
Tree Shrews ◽  
Embryo Cells

A new virus, established as a member of the herpesvirus group by electron microscopy, was isolated from spontaneously degenerating cell cultures derived from the kidneys and lungs of two normal tree shrews. The virus was found to replicate best in cells derived from the homologous species. The cells used were a tree shrew cell line, T-23, which was derived from a spontaneous soft tissue sarcoma. The virus did not multiply or did so poorly for a limited number of passages in human, monkey, rodent, rabbit or chick embryo cells. In the T-23 cells, the virus behaved as members of the subgroup B of herpesvirus, in that the virus remained primarily cell associated.

Effect of elevated potassium on the ion content of mouse astrocytes and neurons

1992 ◽  
Vol 70 (S1) ◽  
pp. S263-S268 ◽  
Author(s):  
H. Steve White ◽  
Sien Yao Chow ◽  
Y. C. Yen-Chow ◽  
Dixon M. Woodbury
Keyword(s):  
Cortical Neurons ◽  
Cell Types ◽  
Mouse Cell ◽  
Ion Concentration ◽  
Cellular Heterogeneity ◽  
Resting Membrane Potential ◽  
Extracellular Potassium ◽  
Individual Response ◽  
Extracellular Potassium Concentration ◽  
The Brain

Potassium is tightly regulated within the extracellular compartment of the brain. Nonetheless, it can increase 3- to 4-fold during periods of intense seizure activity and 10- to 20-fold under certain pathological conditions such as spreading depression. Within the central nervous system, neurons and astrocytes are both affected by shifts in the extracellular concentration of potassium. Elevated potassium can lead to a redistribution of other ions (e.g., calcium, sodium, chloride, hydrogen, etc.) within the cellular compartment of the brain. Small shifts in the extracellular potassium concentration can markedly affect acid–base homeostasis, energy metabolism, and volume regulation of these two brain cells. Since normal neuronal function is tightly coupled to the ability of the surrounding glial cells to regulate ionic shifts within the brain and since both cell types can be affected by shifts in the extracellular potassium, it is important to characterize their individual response to an elevation of this ion. This review describes the results of side-by-side studies conducted on cortical neurons and astrocytes, which assessed the effect of elevated potassium on their resting membrane potential, intracellular volume, and their intracellular concentration of potassium, sodium, and chloride. The results obtained from these studies suggest that there exists a marked cellular heterogeneity between neurons and astrocytes in their response to an elevation in the extracellular potassium concentration.Key words: astrocytes, neurons, ion concentration, neuronal–glial interactions, mouse, cell culture.

scholarly journals SAT-606 Distribution of Beta Klotho Gene Expression in the Mouse Brain

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Bianca S Bono ◽  
Persephone A Miller ◽  
Nikita K Koziel Ly ◽  
Melissa J Chee
Keyword(s):  
Basolateral Amygdala ◽  
Piriform Cortex ◽  
Brain Regions ◽  
Brain Atlas ◽  
Hypothalamic Nucleus ◽  
Fibroblast Growth Factor 21 ◽  
Lateral Olfactory Tract ◽  
Hypothalamic Area ◽  
Low Levels ◽  
The Brain

Abstract Fibroblast growth factor 21 (FGF21) has emerged as a critical endocrine factor for understanding the neurobiology of obesity, such as by the regulation thermogenesis, food preference, and metabolism, as well as for neuroprotection in Alzheimer’s disease and traumatic brain injury. FGF21 is synthesized primarily by the liver and pancreas then crosses the blood brain barrier to exert its effects in the brain. However, the sites of FGF21 action in the brain is not well-defined. FGF21 action requires the activation of FGF receptor 1c as well as its obligate co-receptor beta klotho (KLB). In order to determine the sites of FGF21 action, we mapped the distribution of Klb mRNA by in situ hybridization using RNAscope technology. We labeled Klb distribution throughout the rostrocaudal axis of male wildtype mice by amplifying Klb hybridization using tyramine signal amplification and visualizing Klb hybridization using Cyanine 3 fluorescence. The resulting Klb signal appears as punctate red “dots,” and each Klb neuron may express low (1–4 dots), medium (5–9 dots), or high levels (10+ dots) of Klb hybridization. We then mapped individual Klb expressing neuron to the atlas plates provided by the Allen Brain Atlas in order to determine Klb distribution within the substructures of each brain region, which are defined by Nissl-based parcellations of cytoarchitectural boundaries. The distribution of Klb mRNA is widespread throughout the brain, and the brain regions analyzed thus far point to notable expression in the hypothalamus, amygdala, hippocampus, and the cerebral cortex. The highest expression of Klb was localized to the suprachiasmatic nucleus in the hypothalamus, which contained low and medium Klb-expressing neurons in the lateral hypothalamic area and ventromedial hypothalamic nucleus while low expressing Klb neurons were seen in the paraventricular and dorsmedial hypothalamic nucleus. Hippocampal Klb expression was limited to the dorsal region and largely restricted to the pyramidal cell layer of the dentate gyrus, CA3, CA2, and CA1 but at low levels only. In the amygdala, low and medium Klb expressing cells were seen in lateral amygdala nucleus while low levels were observed in the basolateral amygdala nucleus. Cortical Klb expression analyzed thus far included low Klb-expressing neurons in the olfactory areas, including layers 2 and 3 of piriform cortex and nucleus of the lateral olfactory tract. These findings are consistent with the known roles of FGF21 in the central regulation of energy balance, but also implicates potentially wide-ranging effects of FGF21 such as in executive functions.

scholarly journals Active information maintenance in working memory by a sensory cortex

2018 ◽  
Author(s):  
Xiaoxing Zhang ◽  
Wenjun Yan ◽  
Wenliang Wang ◽  
Hongmei Fan ◽  
Ruiqing Hou ◽  
...  
Keyword(s):  
Working Memory ◽  
Piriform Cortex ◽  
Delay Period ◽  
Sensory Cortex ◽  
Critical Function ◽  
Impaired Performance ◽  
Anterior Piriform Cortex ◽  
Electrophysiological Recordings ◽  
Dual Task Paradigm ◽  
The Brain

SummaryWorking memory is a critical function of the brain to maintain and manipulate information over delay periods of seconds. Sensory areas have been implicated in working memory; however, it is debated whether the delay-period activity of sensory regions is actively maintaining information or passively reflecting top-down inputs. We hereby examined the anterior piriform cortex, an olfactory cortex, in head-fixed mice performing a series of olfactory working memory tasks. Information maintenance is necessary in these tasks, especially in a dual-task paradigm in which mice are required to perform another distracting task while actively maintaining information during the delay period. Optogenetic suppression of the piriform cortex activity during the delay period impaired performance in all the tasks.Furthermore, electrophysiological recordings revealed that the delay-period activity of the anterior piriform cortex encoded odor information with or without the distracting task.Thus, this sensory cortex is critical for active information maintenance in working memory.

scholarly journals Recovery of Brain in Chick Embryos by Growing Second Heart and Brain

2019 ◽  
Vol 7 (18) ◽  
pp. 3085-3089
Author(s):  
Massimo Fioranelli ◽  
Alireza Sepehri ◽  
Maria Grazia Roccia ◽  
Cota Linda ◽  
Chiara Rossi ◽  
...  
Keyword(s):  
Subventricular Zone ◽  
Blood Cells ◽  
Neural Circuits ◽  
Circulatory System ◽  
Egg Cell ◽  
Chick Embryos ◽  
Injured Brain ◽  
Embryo Heart ◽  
Healthy Part ◽  
The Brain

To recover chick embryos damaged the brain, two methods are presented. In both of them, somatic cells of an embryo introduced into an egg cell and an embryo have emerged. In one method, injured a part of the brain in the head of an embryo is replaced with a healthy part of the brain. In the second method, the heart of brain embryo dead is transplanted with the embryo heart. In this mechanism, new blood cells are emerged in the bone marrow and transmit information of transplantation to subventricular zone (SVZ) of the brain through the circulatory system. Then, SVZ produces new neural stem cells by a subsequent dividing into neurons. These neurons produce new neural circuits within the brain and recover the injured brain. To examine the model, two hearts of two embryos are connected, and their effects on neural circuits are observed.  

scholarly journals 6B4 proteoglycan/phosphacan is a repulsive substratum but promotes morphological differentiation of cortical neurons

Development ◽  
1996 ◽  
Vol 122 (2) ◽  
pp. 647-658
Author(s):  
N. Maeda ◽  
M. Noda
Keyword(s):  
Cell Adhesion ◽  
Neurite Outgrowth ◽  
Cortical Neurons ◽  
Tyrosine Phosphatase ◽  
Neuronal Cell ◽  
Morphological Differentiation ◽  
Cell Types ◽  
Thalamic Neurons ◽  
Neurite Extension ◽  
The Brain

6B4 proteoglycan/phosphacan is one of the major phosphate-buffered saline-soluble chondroitin sulfate proteoglycans of the brain. Recently, this molecule has been demonstrated to be an extracellular variant of the proteoglycan-type protein tyrosine phosphatase, PTPzeta (RPTPbeta). The influence of the 6B4 proteoglycan, adsorbed onto the substratum, on cell adhesion and neurite outgrowth was studied using dissociated neurons from the cerebral cortex and thalamus. 6B4 proteoglycan adsorbed onto plastic tissue culture dishes did not support neuronal cell adhesion, but rather exerted repulsive effects on cortical and thalamic neurons. When neurons were densely seeded on patterned substrata consisting of a grid-like structure of alternating poly-L-lysine and 6B4 proteoglycan-coated poly-L-lysine domains, they were concentrated on the poly-L-lysine domains. However, 6B4 proteoglycan did not retard the differentiation of neurons but rather promoted neurite outgrowth and development of the dendrites of cortical neurons, when neurons were sparsely seeded on poly-L-lysine-conditioned coverslips continuously coated with 6B4 proteoglycan. This effect of 6B4 proteoglycan on the neurite extension of cortical neurons was apparent even on coverslips co-coated with fibronectin or tenascin. By contrast, the neurite extension of thalamic neurons was not modified by 6B4 proteoglycan. Chondroitinase ABC or keratanase digestion of 6B4 proteoglycan did not affect its neurite outgrowth promoting activity, but a polyclonal antibody against 6B4 proteoglycan completely suppressed this activity, suggesting that a protein moiety is responsible for the activity. 6B4 proteoglycan transiently promoted tyrosine phosphorylation of an 85x10(3) Mr protein in the cortical neurons, which correlated with the induction of neurite outgrowth. These results suggest that 6B4 proteoglycan/phosphacan modulates morphogenesis and differentiation of neurons dependent on its spatiotemporal distribution and the cell types in the brain.

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