Cortical Development

The cerebral neocortex, a structure unique to the mammalian brain and prerequisite for higher cognitive functions, has since decades attracted the curiosity of neurobiologists and developmental biologists alike. This volume gives a comprehensive and up-to-date overview of early cortical development. It provides concise information on the birth, specification, migration and terminal differentiation of neocortical cells. Both the cellular and molecular events leading to the establishment of a functional neocortex are presented in considerable detail, and possible implications for neurodegenerative diseases are discussed.

Texte du rabat

The cerebral neo cortex, unique to mammals, is regarded as the prerequisite for higher cognitive function and is the structure most closely associated with the idea of the "mind" . Expansion of mental capa city between mammals is most typically associated with an evolutionary increase in neocortical volume that culminates in the intricately folded configuration of sulci and gyri so charac­ teristic of the primate cerebral cortex. Yet, the basic unit structure and funda­ mental connectivity of cortex appears to have been preserved from the smooth cortex of the mouse or rat to the highly convoluted cortical mantle of the human that, if stretched out as a sheet, would be large enough to wrap the entire human brain multiple times. The basic similarity in structure and func­ tion has made it possible to conduct studies in the relatively simple cortices of rat or mouse and have the results pertain to the understanding of the primate, including human, cortex. The neo cortex is an intriguing structure for the study of cell differentiation. Its dozens of neuronal cell types and small handful of different glial types have their origin in a pseudostratified germinal epithelium lining the ventricular surface of the forebrain. In its mature form, neocortex is a six-Iayered struc­ ture; five of its layers contain multiple different but characteristic neuronal types with the sixth occupied by neuronal processes. Various glial cells are dis­ persed throughout all six layers.

Contenu

Population Dynamics During Cell Proliferation and Neuronogenesis in the Developing Murine Neocortex.- References.- Mechanisms Regulating Lineage Diversity During Mammalian Cerebral Cortical Neurogenesis and Gliogenesis.- 1 Stem Cell Biology and Neural Development.- 2 Neural Lineage Elaboration and Bone Morphogenetic Proteins.- 3 Environmental and Transcriptional Regulation of Intermediate Progenitor Species.- 4 Mechanisms Regulating Neuronal and Astroglial Lineage Elaboration.- 5 Developmental Regulation and Lineage Potential of Radial Glia.- 6 Biology of Glial-Restricted Progenitors and the Generation of Oligodendrocytes.- 7 Role of ID Genes and Proteins in BMP-Mediated Cerebral Cortical Neural Fate Decisions.- 8 ID Genes and Proteins.- 8.1 Regulatory Roles.- 8.2 Nervous System Functions.- 9 Summary and Future Directions.- References.- Gap Junctions and Their Implications for Neurogenesis and Maturation of Synaptic Circuitry in the Developing Neocortex.- 1 Introduction.- 1.1 Survey of Neocortical Development.- 1.1.1 Neurogenesis, Migration and Development of Afferents.- 1.1.2 Development of Functional Synapses.- 2 Expression of Gap Junctions in the Neocortex.- 2.1 Expression During the Embryonic Development of the Neocortex.- 2.2 Expression During the Early Postnatal Development of the Neocortex.- 3 Modulation of Gap Junction Permeability During Early Postnatal Stages of Neocortical Development.- 4 Functional Implications of Gap Junctions in the Developing Neocortex.- 4.1 Neurogenesis.- 4.2 Development of Intrinsic Neuronal Properties.- 4.3 Domains, Calcium Oscillations and Circuit Formation.- 4.4 Electrical Coupling of Inhibitory Interneurons.- 5 Concluding Remarks.- References.- Influence of Radial Glia and Cajal-Retzius Cells in Neuronal Migration.- 1 Radial Glial Cells.- 2 Cajal-Retzius Cells and Reelin.- 3 MAM Model.- 4 What Prevents the Normal Laminar Pattern in E24 MAM-Treated Cortex?.- 5 Is There a Radialization Factor in Normal P) Cortex?.- 6 Summary and Conclusions.- References.- Neurotrophins and Cortical Development.- 1 Introduction.- 2 Distribution of the Neurotrophins and Their Receptors.- 2.1 Regulation of the Neurotrophins by Activity.- 2.2 Effects of Activity on Neurotrophin Secretion.- 3 Regulation of Synaptic Plasticity by the Neurotrophins.- 3.1 Acute Effects on Synaptic Function.- 3.2 Long-Term Potentiation and Depression.- 4 Neurotrophins and Structural Synaptic Plasticity.- 4.1 Axonal Growth.- 4.2 Dendritic Growth.- 4.3 Synapse Formation and Maintenance.- 4.4 Activity-Dependent Plasticity.- 5 Concluding Remarks.- References.- Role of Immediate Early Gene Expression in Cortical Morphogenesis and Plasticity.- 1 Neural Activity Plays a Critical Role in the Development of the Cerebral Cortex.- 2 Learning and Development Share Mechanisms of Neural Plasticity.- 3 Molecular Events Underlying Cortical Plasticity: the Immediate Early Gene Response.- 4 Effector Neuronal Immediate Early Genes.- 4.1 Growth Factors: Activin and BDNF.- 4.2 Extracellular Matrix and Signaling Molecules: Arcadlin, tPA, and Narp.- 4.3 Cytoskeletal Molecules: Arc.- 4.4 Signaling Molecules: Rheb and COX-2.- 4.5 Anchoring/Coupling Proteins: Homer.- 5 Conclusions.- References.- Role of Afferent Activity in the Development of Cortical Specification.- 1 Introduction.- 2 Sensory Modalities: Vision and Audition.- 2.1 Visual Processing.- 2.2 Auditory Processing.- 2.3 Vision Versus Audition.- 3 Intrinsic Determination of Modality-Specific Subregions of Cortex.- 4 A Role for Extrinsic Inputs in Specification of Local Cortical Networks.- 4.1 Theoretical Considerations for Experimentally Altering Cortical Inputs.- 4.2 The Rewiring Paradigm.- 4.3 Innervation of the Denervated MGN by the Retina.- 4.4 Physiological Consequences of Rewiring.- 4.5 Analyses of Rewired Al.- 4.5.1 Receptive Field Mapping.- 4.5.2 Optical Imaging of Intrinsic Signals.- 4.5.3 Local Connections Within Al.- 4.6 Other Signaling Mechanisms.- 4.7 Behavior and Effects Downstream of Primary Sensory Cortical Areas.- 4.8 Strategy to Identify and Characterize Cortical Genes Activated by Modality-Specific Inputs.- References.- Regional Forebrain Patterning and Neural Subtype Specification: Implications for Cerebral Cortical Functional Connectivity and the Pathogenesis of Neurodegenerative Diseases.- 1 Introduction.- 2 Role of the Ventral Telencephalon in Cerebral Cortical Development.- 3 Developmental Actions of Neurogenic bHLH Genes.- 4 Mechanisms Regulating the Transition from Neurogenesis to Gliogenesis.- 5 Olig Genes and Regional Shh Signaling.- 6 Importance of Regional Forebrain Patterning for Neural Subtype Specification.- 7 Role of Local BMP Signaling in Cerebral Cortical Neuronal and OL Lineage Elaboration.- 8 Generation of OL Lineage Species in the Adult Brain: Therapeutic Implications.- 9 Role of Gap Junction Channels and GABAergic Neuronal Subtypes in Cerebral Cortical Functional Connectivity.- 10 Regional Forebrain Patterning and Neurodegenerative Diseases.- 11 Summary and Future Directions.- References.