scholarly journals Mathematical modelling of cortical neurogenesis reveals that the founder population does not necessarily scale with neuronal output

2017 ◽  
Author(s):  
Noemi Picco ◽  
Fernando García-Moreno ◽  
Thomas E. Woolley ◽  
Philip K. Maini ◽  
Zoltán Molnár
Keyword(s):  
Mathematical Model ◽  
Mammalian Species ◽  
Founder Population ◽  
Cortical Neurogenesis ◽  
Developmental Program ◽  
Developmental Factors ◽  
Determining Factors ◽  
Neuronal Output ◽  
Cerebral Neocortex ◽  
High Diversity

AbstractThe mammalian cerebral neocortex has a unique structure, composed of layers of different neuron types, interconnected in a stereotyped fashion. While the overall developmental program seems to be conserved, there are divergent developmental factors generating cortical diversity amongst mammalian species. In terms of cortical neuronal numbers some of the determining factors are the size of the founder population, the duration of cortical neurogenesis, the proportion of different progenitor types, and the fine-tuned balance between self-renewing and differentiative divisions. We develop a mathematical model of neurogenesis that, accounting for these factors, aims at explaining the high diversity in neuronal numbers found across mammalian species. By framing our hypotheses in rigorous mathematical terms, we are able to identify paths of neurogenesis that match experimentally observed patterns in mouse, macaque and human. Additionally, we use our model to identify key parameters that would particularly benefit from accurate experimental investigation. We find that the timing of a switch in favor of symmetric neurogenic divisions produces the highest variation in cortical neuronal numbers. Surprisingly, in our model the increase in cortical neuronal numbers does not necessarily reflect a larger size of founder population, a prediction that identified a specific need for experimental quantifications.

Crime, Deprivation and Social Sustainability—Evidence across States in India

2018 ◽  
Vol 12 (3) ◽  
pp. 354-377 ◽  
Author(s):  
Ramprasad Sengupta ◽  
Sovik Mukherjee
Keyword(s):  
Development Strategy ◽  
Social Sustainability ◽  
Left Wing ◽  
Positive Role ◽  
Internal Security ◽  
Developmental Factors ◽  
The Development Strategy ◽  
Determining Factors ◽  
Different Types

We focus in this article on the dimension of social sustainability of the development process— particularly on the determining factors of social tension which results in social disruption in violent forms of the different types of crime—murder, property-related, riots in the presence of polarization and Left-wing insurgency across major states in India. This article makes an attempt to explore the role of economic deprivation—thus, resulting in economic inequality and poverty in addition to infrastructural and other socio-economic developmental factors in determining such crimes in this context. While economic growth has a definite positive role in abating such violent forms of crime and their associated tension, the development strategy should give high priority to literacy, internal security and human development for building up peace and a socially sustainable society in India.

scholarly journals Length of the Neurogenic Period—A Key Determinant for the Generation of Upper-Layer Neurons During Neocortex Development and Evolution

2021 ◽  
Vol 9 ◽  
Author(s):  
Barbara K. Stepien ◽  
Samir Vaid ◽  
Wieland B. Huttner
Keyword(s):  
Cognitive Abilities ◽  
Cortical Neurons ◽  
Mammalian Species ◽  
Critical Role ◽  
Exact Nature ◽  
Cortical Neurogenesis ◽  
Brain Functions ◽  
The Relationship ◽  
Development And Evolution

The neocortex, a six-layer neuronal brain structure that arose during the evolution of, and is unique to, mammals, is the seat of higher order brain functions responsible for human cognitive abilities. Despite its recent evolutionary origin, it shows a striking variability in size and folding complexity even among closely related mammalian species. In most mammals, cortical neurogenesis occurs prenatally, and its length correlates with the length of gestation. The evolutionary expansion of the neocortex, notably in human, is associated with an increase in the number of neurons, particularly within its upper layers. Various mechanisms have been proposed and investigated to explain the evolutionary enlargement of the human neocortex, focussing in particular on changes pertaining to neural progenitor types and their division modes, driven in part by the emergence of human-specific genes with novel functions. These led to an amplification of the progenitor pool size, which affects the rate and timing of neuron production. In addition, in early theoretical studies, another mechanism of neocortex expansion was proposed—the lengthening of the neurogenic period. A critical role of neurogenic period length in determining neocortical neuron number was subsequently supported by mathematical modeling studies. Recently, we have provided experimental evidence in rodents directly supporting the mechanism of extending neurogenesis to specifically increase the number of upper-layer cortical neurons. Moreover, our study examined the relationship between cortical neurogenesis and gestation, linking the extension of the neurogenic period to the maternal environment. As the exact nature of factors promoting neurogenic period prolongation, as well as the generalization of this mechanism for evolutionary distinct lineages, remain elusive, the directions for future studies are outlined and discussed.

scholarly journals Lhx2 regulates the timing of β-catenin-dependent cortical neurogenesis

2015 ◽  
Vol 112 (39) ◽  
pp. 12199-12204 ◽  
Author(s):  
Lea Chia-Ling Hsu ◽  
Sean Nam ◽  
Yi Cui ◽  
Ching-Pu Chang ◽  
Chia-Fang Wang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Transcription Factor ◽  
Radial Glia ◽  
Major Effect ◽  
Cortical Surface ◽  
Temporal Shift ◽  
Homeodomain Transcription Factor ◽  
Cortical Neurogenesis ◽  
Underlying Mechanisms ◽  
Cortical Progenitor

The timing of cortical neurogenesis has a major effect on the size and organization of the mature cortex. The deletion of the LIM-homeodomain transcription factor Lhx2 in cortical progenitors by Nestin-cre leads to a dramatically smaller cortex. Here we report that Lhx2 regulates the cortex size by maintaining the cortical progenitor proliferation and delaying the initiation of neurogenesis. The loss of Lhx2 in cortical progenitors results in precocious radial glia differentiation and a temporal shift of cortical neurogenesis. We further investigated the underlying mechanisms at play and demonstrated that in the absence of Lhx2, the Wnt/β-catenin pathway failed to maintain progenitor proliferation. We developed and applied a mathematical model that reveals how precocious neurogenesis affected cortical surface and thickness. Thus, we concluded that Lhx2 is required for β-catenin function in maintaining cortical progenitor proliferation and controls the timing of cortical neurogenesis.

scholarly journals A stochastic framework of neurogenesis underlies the assembly of neocortical cytoarchitecture

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Alfredo Llorca ◽  
Gabriele Ciceri ◽  
Robert Beattie ◽  
Fong Kuan Wong ◽  
Giovanni Diana ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Cerebral Cortex ◽  
Progenitor Cells ◽  
Cellular Mechanisms ◽  
Cortical Neurogenesis ◽  
Cell Lineages ◽  
Wide Range ◽  
Stochastic Framework ◽  
Combination Of Methods ◽  
Neuronal Output

The cerebral cortex contains multiple areas with distinctive cytoarchitectonic patterns, but the cellular mechanisms underlying the emergence of this diversity remain unclear. Here, we have investigated the neuronal output of individual progenitor cells in the developing mouse neocortex using a combination of methods that together circumvent the biases and limitations of individual approaches. Our experimental results indicate that progenitor cells generate pyramidal cell lineages with a wide range of sizes and laminar configurations. Mathematical modeling indicates that these outcomes are compatible with a stochastic model of cortical neurogenesis in which progenitor cells undergo a series of probabilistic decisions that lead to the specification of very heterogeneous progenies. Our findings support a mechanism for cortical neurogenesis whose flexibility would make it capable to generate the diverse cytoarchitectures that characterize distinct neocortical areas.

scholarly journals Interacting circadian and homeostatic processes with opportunity cost: A mathematical model of sleep with application to two mammalian species

PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0208043
Author(s):  
James H. Cardon ◽  
Eric R. Eide ◽  
Kerk L. Phillips ◽  
Mark H. Showalter
Keyword(s):  
Mathematical Model ◽  
Opportunity Cost ◽  
Mammalian Species

scholarly journals Mathematical Modeling of Cortical Neurogenesis Reveals that the Founder Population does not Necessarily Scale with Neurogenic Output

2018 ◽  
Vol 28 (7) ◽  
pp. 2540-2550 ◽  
Author(s):  
Noemi Picco ◽  
Fernando García-Moreno ◽  
Philip K Maini ◽  
Thomas E Woolley ◽  
Zoltán Molnár
Keyword(s):  
Mathematical Modeling ◽  
Founder Population ◽  
Cortical Neurogenesis

scholarly journals How neural stem cells contribute to neocortex development

2021 ◽  
Author(s):  
Lei Xing ◽  
Michaela Wilsch-Bräuninger ◽  
Wieland B. Huttner
Keyword(s):  
Cortical Neurons ◽  
Neural Progenitor Cells ◽  
Mammalian Species ◽  
Cellular Behavior ◽  
Cortical Neurogenesis ◽  
Biological Features ◽  
Neocortical Development ◽  
Proliferation And Differentiation ◽  
Different Types ◽  
Higher Cognitive Functions

The mammalian neocortex is the seat of higher cognitive functions, such as thinking and language in human. A hallmark of the neocortex are the cortical neurons, which are generated from divisions of neural progenitor cells (NPCs) during development, and which constitute a key feature of the well-organized layered structure of the neocortex. Proper formation of neocortex structure requires an orchestrated cellular behavior of different cortical NPCs during development, especially during the process of cortical neurogenesis. Here, we review the great diversity of NPCs and their contribution to the development of the neocortex. First, we review the categorization of NPCs into different classes and types based on their cell biological features, and discuss recent advances in characterizing marker expression and cell polarity features in the different types of NPCs. Second, we review the different modes of cell divisions that NPCs undergo and discuss the importance of the balance between proliferation and differentiation of NPCs in neocortical development. Third, we review the different proliferative capacities among different NPC types and among the same type of NPC in different mammalian species. Dissecting the differences between NPC types and differences among mammalian species is beneficial to further understand the development and the evolutionary expansion of the neocortex and may open up new therapeutic avenues for neurodevelopmental and psychiatric disorders.

scholarly journals Hominin-specific NOTCH2 paralogs expand human cortical neurogenesis through regulation of Delta/Notch interactions

2017 ◽  
Author(s):  
Ikuo K. Suzuki ◽  
David Gacquer ◽  
Roxane Van Heurck ◽  
Devesh Kumar ◽  
Marta Wojno ◽  
...  
Keyword(s):  
Human Brain ◽  
Notch Pathway ◽  
Brain Evolution ◽  
Rapid Expansion ◽  
Specific Gene ◽  
Human Cortex ◽  
Cortical Neurogenesis ◽  
Human Brain Evolution ◽  
Large Repertoire ◽  
Neuronal Output

SummaryThe human cerebral cortex has undergone rapid expansion and increased complexity during recent evolution. Hominid-specific gene duplications represent a major driving force of evolution, but their impact on human brain evolution remains unclear. Using tailored RNA sequencing (RNAseq), we profiled the spatial and temporal expression of Hominid-specific duplicated (HS) genes in the human fetal cortex, leading to the identification of a repertoire of 36 HS genes displaying robust and dynamic patterns during cortical neurogenesis. Among these we focused on NOTCH2NL, previously uncharacterized HS paralogs of NOTCH2. NOTCH2NL promote the clonal expansion of human cortical progenitors by increasing self-renewal, ultimately leading to higher neuronal output. NOTCH2NL function by activating the Notch pathway, through inhibition of Delta/Notch interactions. Our study uncovers a large repertoire of recently evolved genes linking genomic evolution to human brain development, and reveals how hominin-specific NOTCH paralogs may have contributed to the expansion of the human cortex.

The parent-offspring microbiome and neurobehavioral development

2019 ◽  
Vol 42 ◽  
Author(s):  
Jeffrey R. Alberts ◽  
Christopher Harshaw ◽  
Gregory E. Demas ◽  
Cara L. Wellman ◽  
Ardythe L. Morrow
Keyword(s):  
Mammalian Species ◽  
Social Emotional ◽  
Behavioral Measures ◽  
Neurobehavioral Development ◽  
Emotional Function ◽  
Neurobehavioral Outcomes ◽  
Methodological Approaches ◽  
And Behavior

Abstract We identify the significance and typical requirements of developmental analyses of the microbiome-gut-brain (MGB) in parents, offspring, and parent-offspring relations, which have particular importance for neurobehavioral outcomes in mammalian species, including humans. We call for a focus on behavioral measures of social-emotional function. Methodological approaches to interpreting relations between the microbiota and behavior are discussed.

Androgen-induced plasticity at a “vocal” neuromuscular synapse

1994 ◽  
Vol 52 ◽  
pp. 32-33
Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman
Keyword(s):  
Xenopus Laevis ◽  
Motor Neurons ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Neuromuscular Synapse ◽  
Sexually Dimorphic ◽  
Intracellular Protein ◽  
Developmental Program ◽  
Androgen Action ◽  
Clawed Frog

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.

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