Information about Neural Development
The study of neural development draws on both neuroscience and developmental biology to describe the cellular and molecular mechanisms by which complex nervous systems emerge during embryonic development and throughout life.
Some landmarks of embryonic neural development include the birth and differentiation of neurons from stem cell precursors, the migration of immature neurons from their birthplaces in the embryo to their final positions, outgrowth of axons from neurons and guidance of the motile growth cone through the embryo towards postsynaptic partners, the generation of synapses between these axons and their postsynaptic partners, and finally the lifelong changes in synapses which are thought to underlie learning and memory.
Typically, these neurodevelopmental processes can be broadly divided into two classes: activity-independent mechanisms and activity-dependent mechanisms. Activity-independent mechanisms are generally believed to occur as hardwired processes determined by genetic programs played out within individual neurons. These include differentiation, migration and axon guidance to their initial target areas. These processes are thought of as being independent of neural activity and sensory experience. Once axons reach their target areas, activity-dependent mechanisms come into play. Neural activity and sensory experience will mediate formation of new synapses, as well as synaptic plasticity, which will be responsible for refinement of the nascent neural circuits.
Developmental neuroscience uses a variety of animal models including the fruit fly Drosophila melanogaster , the zebrafish Danio rerio, Xenopus laevis tadpoles and the worm Caenorhabditis elegans, among others.
After gastrulation the notochord - a flexible, rod-shaped body that runs along the antero-posterior axis - has been formed (derived from mesoderm). The notochord sends signals to the overlying ectoderm, inducing it to become neuroectoderm, composed of neuronal precursor (or stem) cells. This is evidenced by a thickening of the ectoderm above the notochord, the neural plate. The neural plate will form the neural tube which then twists, turns and kinks to form the three primary brain vesicles and five secondary brain vesicles. The end result of this process is described in the article on the regions of the brain.
Subsequent waves of neurons split the preplate by migrating along radial glial fibres to form the cortical plate. Each wave of migrating cells travel past their predecessors forming layers in an inside-out manner, meaning that the youngest neurons are the closest to the surface.[2][3] It is estimated that glial guided migration represents 80-90% of migrating neurons.
Multipolar migration...[4][5] "<<expand this bit>>"
Morphogenesis (from the Greek morphê shape and genesis creation) is one of three fundamental aspects of developmental biology along with the control of cell growth and cellular differentiation.
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Some landmarks of embryonic neural development include the birth and differentiation of neurons from stem cell precursors, the migration of immature neurons from their birthplaces in the embryo to their final positions, outgrowth of axons from neurons and guidance of the motile growth cone through the embryo towards postsynaptic partners, the generation of synapses between these axons and their postsynaptic partners, and finally the lifelong changes in synapses which are thought to underlie learning and memory.
Typically, these neurodevelopmental processes can be broadly divided into two classes: activity-independent mechanisms and activity-dependent mechanisms. Activity-independent mechanisms are generally believed to occur as hardwired processes determined by genetic programs played out within individual neurons. These include differentiation, migration and axon guidance to their initial target areas. These processes are thought of as being independent of neural activity and sensory experience. Once axons reach their target areas, activity-dependent mechanisms come into play. Neural activity and sensory experience will mediate formation of new synapses, as well as synaptic plasticity, which will be responsible for refinement of the nascent neural circuits.
Developmental neuroscience uses a variety of animal models including the fruit fly Drosophila melanogaster , the zebrafish Danio rerio, Xenopus laevis tadpoles and the worm Caenorhabditis elegans, among others.
First stage: neurulation
- See embryogenesis for understanding the animal development up to this stage.
After gastrulation the notochord - a flexible, rod-shaped body that runs along the antero-posterior axis - has been formed (derived from mesoderm). The notochord sends signals to the overlying ectoderm, inducing it to become neuroectoderm, composed of neuronal precursor (or stem) cells. This is evidenced by a thickening of the ectoderm above the notochord, the neural plate. The neural plate will form the neural tube which then twists, turns and kinks to form the three primary brain vesicles and five secondary brain vesicles. The end result of this process is described in the article on the regions of the brain.
Human brain development
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Highly schematic flowchart of human brain development.
Neuronal migration
Neuronal migration is the method by which neurons travel from their origin or birth place to their final position in the brain.Radial migration
Neuronal precursor cells proliferate in the ventricular zone of the developing neocortex. The first postmitotic cells to migrate form the preplate which are destined to become Cajal-Retzius cells and subplate neurons. These cells do so by somal translocation. Neurons migrating with this mode of locomotion are bipolar and attachs the leading edge of the process to the pia. The soma is then transported to the pial surface by nucleokenisis, a process by which a microtubule "cage" around the nucleus elongates and contracts in association with the centrosome to guide the nucleus to its final destination.[1] Radial fibres (also known as radial glia) can translocate to the cortical plate and differentiate either into astrocytes or neurons. Somal translocation can occur at any time during development.<ref name "Nadar1">Nadarajah B, Brunstrom J, Grutzendler J, Wong R, Pearlman A (2001). "Two modes of radial migration in early development of the cerebral cortex". Nat Neurosci 4 (2): 143-50. PMID 11175874.Subsequent waves of neurons split the preplate by migrating along radial glial fibres to form the cortical plate. Each wave of migrating cells travel past their predecessors forming layers in an inside-out manner, meaning that the youngest neurons are the closest to the surface.[2][3] It is estimated that glial guided migration represents 80-90% of migrating neurons.
Multipolar migration...[4][5] "<<expand this bit>>"
Tangential migration
"Most interneurons migrate tangentially through multiple modes of migration to reach their appropriate location in the cortex." An example of tangential migration is the movement of Cajal-Retzius cells from the ganglionic eminence to the cerebral cortex.Neural development in the adult nervous system
See Neuroregeneration.See also
- Time lapse seqeunces of radial migration (also known as glial guidance) and somal translocation.<ref name "Nadar1">Nadarajah B, Brunstrom J, Grutzendler J, Wong R, Pearlman A (2001). "Two modes of radial migration in early development of the cerebral cortex". Nat Neurosci 4 (2): 143-50. PMID 11175874.
- Axon guidance
- Neural Darwinism
- Pre- and perinatal psychology
References
1. ^ Samuels B, Tsai L (2004). "Nucleokinesis illuminated". Nat Neurosci 7 (11): 1169-70. PMID 15508010.
2. ^ Nadarajah B, Parnavelas J (2002). "Modes of neuronal migration in the developing cerebral cortex". Nat Rev Neurosci 3 (6): 423-32. PMID 12042877.
3. ^ Rakic P (1972). "Mode of cell migration to the superficial layers of fetal monkey neocortex". J Comp Neurol 145 (1): 61-83. PMID 4624784.
4. ^ Tabata H, Nakajima K (2003). "Multipolar migration: the third mode of radial neuronal migration in the developing cerebral cortex". J Neurosci 23 (31): 9996-10001. PMID 14602813. Full text
5. ^ Nadarajah B, Alifragis P, Wong R, Parnavelas J (2003). "Neuronal migration in the developing cerebral cortex: observations based on real-time imaging". Cereb Cortex 13 (6): 607-11. PMID 12764035. Full text
2. ^ Nadarajah B, Parnavelas J (2002). "Modes of neuronal migration in the developing cerebral cortex". Nat Rev Neurosci 3 (6): 423-32. PMID 12042877.
3. ^ Rakic P (1972). "Mode of cell migration to the superficial layers of fetal monkey neocortex". J Comp Neurol 145 (1): 61-83. PMID 4624784.
4. ^ Tabata H, Nakajima K (2003). "Multipolar migration: the third mode of radial neuronal migration in the developing cerebral cortex". J Neurosci 23 (31): 9996-10001. PMID 14602813. Full text
5. ^ Nadarajah B, Alifragis P, Wong R, Parnavelas J (2003). "Neuronal migration in the developing cerebral cortex: observations based on real-time imaging". Cereb Cortex 13 (6): 607-11. PMID 12764035. Full text
External links
- Myers, P.Z., 2004. "Neurulation in Zebrafish" in Pharyngula http://pharyngula.org/index/weblog/neurulation_in_zebrafish/.
Prenatal development/Mammalian development of nervous system | |
|---|---|
| General neural development/Neurulation | Neurula - Notochord - Neural folds - Neuroectoderm - Neural plate - Neural groove Neural crest - Neural tube (Neuromere/Rhombomere, Cephalic flexure) |
| Eye development | Optic vesicles - Optic stalk - Optic cup |
| Auditory development | Auditory vesicle - Auditory pit |
Neuroscience is a field that is devoted to the scientific study of the nervous system. Such studies may include the structure, function, evolutionary history, development, genetics, biochemistry, physiology, pharmacology, and pathology of the nervous system.
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Developmental Biology is the official journal of the Society for Developmental Biology. It publishes research on the mechanisms of development, differentiation, and growth in animals and plants at the molecular, cellular, and genetic levels.
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nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and also stops input from the senses, and initiates actions. Prominent parts of a nervous system include neurons and nerves, which are used in coordination.
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For the band, see .
Morphogenesis (from the Greek morphê shape and genesis creation) is one of three fundamental aspects of developmental biology along with the control of cell growth and cellular differentiation.
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Cellular differentiation is a concept from developmental biology describing the process by which cells acquire a "type". The morphology of a cell may change dramatically during differentiation, but the genetic material remains the same, with few exceptions.
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Neurons (also known as neurones and nerve cells) are electrically excitable cells in the nervous system that process and transmit information. In vertebrate animals, neurons are the core components of the brain, spinal cord and peripheral nerves.
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Stem cells are primal cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types.
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Cellular migration is the movement of cells in the body to their proper position.
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Purpose
During the Prenatal development, the basic structures for all organs in the body are created...... Click the link for more information.
axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma.
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Anatomy
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Axon guidance (also called axon pathfinding) is a subfield of neural development concerning the process by which neurons send out axons to reach the correct targets.
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A growth cone is a dynamic, actin-supported extension of a developing axon seeking its synaptic target. Their existence was originally proposed by Spanish histologist Santiago Ramón y Cajal based upon stationary images he observed under the microscope.
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synapse. Synapses allow nerve cells to communicate with one another through axons and dendrites, converting electrical impulses into chemical signals.]]
Chemical synapses
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Chemical synapses
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synaptic plasticity is the ability of the connection, or synapse, between two neurons to change in strength. There are several underlying mechanisms that cooperate to achieve synaptic plasticity, including changes in the quantity of neurotransmitter released into a synapse and
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Cellular differentiation is a concept from developmental biology describing the process by which cells acquire a "type". The morphology of a cell may change dramatically during differentiation, but the genetic material remains the same, with few exceptions.
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Cellular migration is the movement of cells in the body to their proper position.
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Purpose
During the Prenatal development, the basic structures for all organs in the body are created...... Click the link for more information.
Axon guidance (also called axon pathfinding) is a subfield of neural development concerning the process by which neurons send out axons to reach the correct targets.
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axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma.
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Anatomy
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synapse. Synapses allow nerve cells to communicate with one another through axons and dendrites, converting electrical impulses into chemical signals.]]
Chemical synapses
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Chemical synapses
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synaptic plasticity is the ability of the connection, or synapse, between two neurons to change in strength. There are several underlying mechanisms that cooperate to achieve synaptic plasticity, including changes in the quantity of neurotransmitter released into a synapse and
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D. melanogaster
Binomial name
Drosophila melanogaster
Meigen, 1830[1]
Drosophila melanogaster (from the Greek for black-bellied dew-lover
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Binomial name
Drosophila melanogaster
Meigen, 1830[1]
Drosophila melanogaster (from the Greek for black-bellied dew-lover
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X. laevis
Binomial name
Xenopus laevis
Daudin, 1802
The African clawed frog (Xenopus laevis, also known as platanna) is a species of South African aquatic frog of the genus
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Binomial name
Xenopus laevis
Daudin, 1802
The African clawed frog (Xenopus laevis, also known as platanna) is a species of South African aquatic frog of the genus
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elegans
Binomial name
Caenorhabditis elegans
Maupas, 1900
Caenorhabditis elegans (IPA:
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Binomial name
Caenorhabditis elegans
Maupas, 1900
Caenorhabditis elegans (IPA:
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Neurulation is a part of organogenesis in vertebrate embryos. Steps of neurulation include the formation of the dorsal nerve cord, and the eventual formation of the central nervous system.
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Embryogenesis is the process by which the embryo is formed and develops. It starts with the fertilization of the ovum, egg, which, after fertilization, is then called a zygote.
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Gastrulation is a phase early in the development of animal embryos, during which the morphology of the embryo is dramatically restructured by cell migration. Gastrulation varies in different phyla.
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germ layer is a collection of cells, formed during animal embryogenesis. Germ layers are only really pronounced in the vertebrates. However, all animals more complex than sponges (eumetazoans and ) produce two or three primary tissue layers
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Skin layers: epidermis, dermis, and subcutis, showing a hair follicle, sweat gland & sebaceous gland.]] In zootomy and dermatology, skin is the largest organ of the integumentary system made up of multiple layers of epithelial tissues that guard underlying muscles and organs.
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gastrointestinal tract (GI tract), also called the digestive tract, or the alimentary canal, is the system of organs within multicellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste.
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