scholarly journals Development and Evolution of Cerebral and Cerebellar Cortex

2018 ◽  
Vol 91 (3) ◽  
pp. 158-169 ◽  
Author(s):  
David C. Van Essen ◽  
Chad J. Donahue ◽  
Matthew F. Glasser
Keyword(s):  
Cerebral Cortex ◽  
Cerebellar Cortex ◽  
Recent Progress ◽  
Functional Organization ◽  
Mechanical Tension ◽  
Developmental Processes ◽  
Cortical Areas ◽  
Methodological Challenges ◽  
Evolutionarily Conserved ◽  
Development And Evolution

Cerebral cortex and cerebellar cortex both vary enormously across species in their size and complexity of convolutions. We discuss the development and evolution of cortical structures in terms of anatomy and functional organization. We propose that the distinctive shapes of cerebral and cerebellar cortex can be explained by relatively few developmental processes, notably including mechanical tension along axons and dendrites. Regarding functional organization, we show how maps of myelin content in cerebral cortex are evolutionarily conserved across primates but differ in the proportion of cortex devoted to sensory, cognitive, and other functions. We summarize recent progress and challenges in (i) parcellating cerebral cortex into a mosaic of distinct areas, (ii) distinguishing cortical areas that correspond across species from those that are present in one species but not another, and (iii) using this information along with surface-based interspecies registration to gain deeper insights into cortical evolution. We also comment on the methodological challenges imposed by the differences in anatomical and functional organization of cerebellar cortex relative to cerebral cortex.

scholarly journals Functional Territories of Human Dentate Nucleus

2019 ◽  
Vol 30 (4) ◽  
pp. 2401-2417 ◽  
Author(s):  
Xavier Guell ◽  
Anila M D’Mello ◽  
Nicholas A Hubbard ◽  
Rachel R Romeo ◽  
John D E Gabrieli ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Cerebellar Cortex ◽  
Broad Spectrum ◽  
Neural Control ◽  
Functional Organization ◽  
Neural Processing ◽  
Functional Neuroanatomy ◽  
Default Mode ◽  
Healthy Humans ◽  
Spatio Temporal

Abstract Anatomical connections link the cerebellar cortex with multiple sensory, motor, association, and paralimbic cerebral areas. The majority of fibers that exit cerebellar cortex synapse in dentate nuclei (DN) before reaching extracerebellar structures such as cerebral cortex, but the functional neuroanatomy of human DN remains largely unmapped. Neuroimaging research has redefined broad categories of functional division in the human brain showing that primary processing, attentional (task positive) processing, and default-mode (task negative) processing are three central poles of neural macroscale functional organization. This broad spectrum of human neural processing categories is represented not only in the cerebral cortex, but also in the thalamus, striatum, and cerebellar cortex. Whether functional organization in DN obeys a similar set of macroscale divisions, and whether DN are yet another compartment of representation of a broad spectrum of human neural processing categories, remains unknown. Here, we show for the first time that human DN are optimally divided into three functional territories as indexed by high spatio-temporal resolution resting-state MRI in 77 healthy humans, and that these three distinct territories contribute uniquely to default-mode, salience-motor, and visual cerebral cortical networks. Our findings provide a systems neuroscience substrate for cerebellar output to influence multiple broad categories of neural control.

scholarly journals Functional Territories of Human Dentate Nucleus

2019 ◽  
Author(s):  
Xavier Guell ◽  
Anila M D’Mello ◽  
Nicholas A Hubbard ◽  
Rachel R Romeo ◽  
John DE Gabrieli ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Cerebellar Cortex ◽  
Broad Spectrum ◽  
Brain Function ◽  
Functional Organization ◽  
Data Driven ◽  
Neural Processing ◽  
Functional Neuroanatomy ◽  
Default Mode ◽  
Macro Scale

ABSTRACTAnatomical connections link the cerebellar cortex with multiple distinct sensory, motor, association, and paralimbic areas of the cerebrum. These projections allow a topographically precise cerebellar modulation of multiple domains of neurological function, and underscore the relevance of the cerebellum for the pathophysiology of numerous disorders in neurology and psychiatry. The majority of fibers that exit the cerebellar cortex synapse in the dentate nuclei (DN) before reaching extracerebellar structures such as cerebral cortex. Although the DN have a central position in the anatomy of the cerebello-cerebral circuits, the functional neuroanatomy of human DN remains largely unmapped. Neuroimaging research has redefined broad categories of functional division in the human brain showing that primary processing, attentional (task positive) processing, and default-mode (task negative) processing are three central poles of neural macro-scale functional organization. This new macro-scale understanding of the range and poles of brain function has revealed that a broad spectrum of human neural processing categories (primary, task positive, task negative) is represented not only in the cerebral cortex, but also in the thalamus, striatum, and cerebellar cortex. Whether functional organization in DN obeys a similar set of macroscale divisions, and whether DN are yet another compartment of representation of a broad spectrum of human neural processing categories, remains unknown. Here we show for the first time that human DN is optimally divided into three functional territories as indexed by high spatio-temporal resolution resting-state MRI in 60 healthy adolescents, and that these three distinct territories contribute uniquely to default-mode, salience-motor, and visual brain networks. These conclusions are supported by novel analytical strategies in human studies of DN organization, including 64-channel MRI imaging, data-driven methods, and replication in an independent sample. Our findings provide a systems neuroscience substrate for cerebellar output to influence multiple broad categories of neural control - namely default- mode, attentional, and multiple unimodal streams of information processing including motor and visual. They also provide a validated data-driven mapping of functions in human DN, crucial for the design of methodology and interpretation of results in future neuroimaging studies of brain function and dysfunction.

Characterization of the Inner and Outer Fiber Layers in the Developing Cerebral Cortex of Gyrencephalic Ferrets

2018 ◽  
Vol 29 (10) ◽  
pp. 4303-4311
Author(s):  
Kengo Saito ◽  
Keishi Mizuguchi ◽  
Toshihide Horiike ◽  
Tung Anh Dinh Duong ◽  
Yohei Shinmyo ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
In Utero ◽  
In Utero Electroporation ◽  
Fiber Layer ◽  
Developmental Processes ◽  
Cortical Areas ◽  
Shed Light ◽  
Outer Fiber

Abstract Changes in the cerebral cortex of mammals during evolution have been of great interest. Ferrets, monkeys, and humans have more developed cerebral cortices compared with mice. Although the features of progenitors in the developing cortices of these animals have been intensively investigated, those of the fiber layers are still largely elusive. By taking the advantage of our in utero electroporation technique for ferrets, here we systematically investigated the cellular origins and projection patterns of axonal fibers in the developing ferret cortex. We found that ferrets have 2 fiber layers in the developing cerebral cortex, as is the case in monkeys and humans. Axonal fibers in the inner fiber layer projected contralaterally and subcortically, whereas those in the outer fiber layer sent axons to neighboring cortical areas. Furthermore, we performed similar experiments using mice and found unexpected similarities between ferrets and mice. Our results shed light on the cellular origins, the projection patterns, the developmental processes, and the evolution of fiber layers in mammalian brains.

THE METABOLISM OF NORMAL BRAIN AND HUMAN GLIOMAS IN RELATION TO CELL TYPE AND DENSITY

1955 ◽  
Vol 33 (3) ◽  
pp. 395-403 ◽  
Author(s):  
Irving H. Heller ◽  
K. A. C. Elliott
Keyword(s):  
Cerebral Cortex ◽  
White Matter ◽  
Brain Tumors ◽  
Corpus Callosum ◽  
Oxygen Uptake ◽  
Glial Cells ◽  
Cerebellar Cortex ◽  
Unit Weight ◽  
Uptake Rates ◽  
The Brain

Per unit weight, cerebral and cerebellar cortex respire much more actively than corpus callosum. The rate per cell nucleus is highest in cerebral cortex, lower in corpus callosum, and still lower in cerebellar cortex. The oxygen uptake rates of the brain tumors studied, with the exception of an oligodendroglioma, were about the same as that of white matter on the weight basis but lower than that of cerebral cortex or white matter on the cell basis. In agreement with previous work, an oligodendroglioma respired much more actively than the other tumors. The rates of glycolysis of the brain tumors per unit weight were low but, relative to their respiration rate, glycolysis was higher than in normal gray or white matter. Consideration of the figures obtained leads to the following tentative conclusions: Glial cells of corpus callosum respire more actively than the neurons of the cerebellar cortex. Neurons of the cerebral cortex respire on the average much more actively than neurons of the cerebellar cortex or glial cells. Considerably more than 70% of the oxygen uptake by cerebral cortex is due to neurons. The oxygen uptake rates of normal oligodendroglia and astrocytes are probably about the same as the rates found per nucleus in an oligodendroglioma and in astrocytomas; oligodendroglia respire much more actively than astrocytes.

Implications of DNA replication for eukaryotic gene expression

1991 ◽  
Vol 99 (2) ◽  
pp. 201-206 ◽  
Author(s):  
A.P. Wolffe
Keyword(s):  
Gene Expression ◽  
Dna Replication ◽  
Replication Fork ◽  
Recent Progress ◽  
Gene Activity ◽  
Nucleosome Assembly ◽  
Developmental Processes ◽  
Eukaryotic Gene Expression ◽  
Eukaryotic Gene

DNA replication has a key role in many developmental processes. Recent progress in understanding events at the replication fork suggests mechanisms for both establishing and maintaining programs of eukaryotic gene activity. In this review, I discuss the consequences of replication fork passage for preexisting chromatin structures and describe how the mechanism of nucleosome assembly at the replication fork may facilitate the formation of either transcriptionally active or repressed chromatin.

scholarly journals The lizard cerebral cortex as a model to study neuronal regeneration

2002 ◽  
Vol 74 (1) ◽  
pp. 85-104 ◽  
Author(s):  
CARLOS LOPEZ-GARCIA ◽  
ASUNCION MOLOWNY ◽  
JUAN NACHER ◽  
XAVIER PONSODA ◽  
FRANCISCO SANCHO-BIELSA ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Neuronal Death ◽  
Cell Layer ◽  
Neuronal Regeneration ◽  
Postnatal Neurogenesis ◽  
Continuous Growth ◽  
Cortical Areas ◽  
Medial Cortex ◽  
Chemical Lesion ◽  
Neuroblast Proliferation

The medial cerebral cortex of lizards, an area homologous to the hippocampal fascia dentata, shows delayed postnatal neurogenesis, i.e., cells in the medial cortex ependyma proliferate and give rise to immature neurons, which migrate to the cell layer. There, recruited neurons differentiate and give rise to zinc containing axons directed to the rest of cortical areas, thus resulting in a continuous growth of the medial cortex and its zinc-enriched axonal projection. This happens along the lizard life span, even in adult lizards, thus allowing one of their most important characteristics: neuronal regeneration. Experiments in our laboratory have shown that chemical lesion of the medial cortex (affecting up to 95% of its neurons) results in a cascade of events: first, massive neuronal death and axonal-dendritic retraction and, secondly, triggered ependymal-neuroblast proliferation and subsequent neo-histogenesis and regeneration of an almost new medial cortex, indistinguishable from a normal undamaged one. This is the only case to our knowledge of the regeneration of an amniote central nervous centre by new neuron production and neo-histogenesis. Thus the lizard cerebral cortex is a good model to study neuronal regeneration and the complex factors that regulate its neurogenetic, migratory and neo-synaptogenetic events.

Development and evolution

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Evolutionary Biology ◽  
Recent Progress ◽  
Sound Production ◽  
Germ Line ◽  
Black Box ◽  
Developmental Genetics ◽  
Morphological Form ◽  
Molecular Information ◽  
Acquired Characters ◽  
Development And Evolution

In the nineteenth century, ideas about development, heredity and evolution were inextricably mixed up, because it seemed natural to suppose that changes that first occurred in development could become hereditary, and so could contribute to evolution. This was not only Lamarck’s view but Darwin’s, expressed in his theory of pangenesis. Weismann liberated us from this confusion, by arguing that information could pass from germ line to soma, but not from soma to germ line. If he was right, geneticists and evolutionary biologists could treat development as a black box: transmission genetics and evolution could be understood without first having to understand development. Since Weismann, developmental biology has had only a rather marginal impact on evolutionary biology. One day, we have promised ourselves, we will open the box, but for the time being we can get along very nicely without doing so. Recent progress in developmental genetics, some of which has been reviewed in the last three chapters, oblige us to reopen the question. In fact, there are three related questions, not one. The first, which is most relevant to the theme of this book, is the ‘levels of selection’ question: why does not selection between the cells of an organism disrupt integration at the level of the organism? This is the topic of section 15.2. The second is the problem of the inheritance of acquired characters. This old problem has reappeared in a new guise. We now recognize the existence of cell heredity, mediated by different mechanisms from those concerned with transmitting information between generations. In section 15.3, we discuss whether cell heredity plays any role in evolutionary change. Finally, in sections 15.4 and 15.5, we ask whether recent molecular information sheds any light on another old problem—that of the extraordinary conservatism of morphological form, maintained despite dramatic changes of function. This conservatism has led anatomists to identify a small number of basic archetypes, or bauplans. There is little doubt that conservatism is real. Consider, for example, the fact that bones and cartilages, which in humans serve in swallowing, sound production and hearing, are derived from elements of the gill apparatus whereby our fish ancestors exchanged gases with seawater, and, before that, in all probability, from elements of a filter-feeding apparatus.

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