neural divergence
(noun)
When a neuron fires and the signal is sent to many other neurons.
Examples of neural divergence in the following topics:
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Functions of the Cerebellum
- Although a full understanding of cerebellar function has remained elusive, at least four principles have been identified as important: feedforward processing, divergence and convergence, modularity, and plasticity.
- This feedforward mode of operation means that the cerebellum, in contrast to the cerebral cortex, cannot generate self-sustaining patterns of neural activity.
- Divergence and convergence: In the human cerebellum, information from 200 million mossy fiber inputs is expanded to 40 billion granule cells.
- This neural divergence is followed by parallel fiber outputs that converge onto 15 million Purkinje cells.
- Due to their longitudinal alignment, the approximately 1000 Purkinje cells belonging to a microzone may receive input via neural convergence from as many as 100 million parallel fibers.
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Modulation of Movement by the Cerebellum
- This feedforward mode of operation means that the cerebellum cannot generate self-sustaining patterns of neural activity, in contrast to the cerebral cortex.
- This complex neural network gives rise to a massive signal-processing capability, but almost all of its output is directed to a set of small, deep cerebellar nuclei lying in the interior of the cerebellum.
- Although a full understanding of cerebellar function remains elusive, at least four principles are identified as important: 1) feedforward processing, 2) divergence and convergence, 3) modularity, and 4) plasticity.
- This means that the cerebellum, in contrast to the cerebral cortex, cannot generate self-sustaining patterns of neural activity.
- Divergence and convergence: The 1000 or so Purkinje cells belonging to a microzone may receive input from as many as 100 million parallel fibers, and focus their own output down to a group of less than 50 deep nuclear cells.
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Development of the Peripheral Nervous System
- The peripheral nervous system develops from two strips of tissue called the neural crest, running lengthwise above the neural tube.
- At this point the future CNS appears as a cylindrical structure called the neural tube, whereas the future PNS appears as two strips of tissue called the neural crest, running lengthwise above the neural tube.
- The sequence of stages from neural plate to neural tube and neural crest is known as neurulation .
- After gastrulation, neural crest cells are specified at the border of the neural plate and the non-neural ectoderm.
- During neurulation, the borders of the neural plate, also known as the neural folds, converge at the dorsal midline to form the neural tube.
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Embryonic Development
- The neural groove gradually deepens as the neural folds become elevated, and ultimately the folds meet and coalesce in the middle line and convert the groove into a closed tube, the neural tube or neural canal, the ectodermal wall of which forms the rudiment of the nervous system.
- Primary neurulation begins after the neural plate has formed.
- The edges of the neural plate start to thicken and lift upward, forming the neural folds.
- The center of the neural plate remains grounded allowing a U-shaped neural groove to form.
- The neural folds pinch in towards the midline of the embryo and fuse together to form the neural tube.
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Neurulation
- Neurulation is the formation of the neural tube from the ectoderm of the embryo.
- The neural plate folds outwards to form the neural groove.
- Beginning in the future neck region, the neural folds of this groove close to create the neural tube (this form of neurulation is called primary neurulation).
- The hollow interior is called the neural canal.
- Transverse sections that show the progression of the neural plate into the neural tube.
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Development of Vision
- The eye forms from the neural tube, epidermis, and periocular mesenchyme, with sequential inductions of tissue during development.
- The eye develops from the neural tube, the epidermis, and the periocular mesenchyme, which receives contributions from both the neural crest and mesoderm lineages.
- First, an outpocketing of the neural tube occurs, creating optic vesicles.
- The optic cup then delaminates into two layers: the neural retina and the retinal pigment epithelium.
- The eyes make their appearance before the closure of the anterior end of the neural tube.
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Embryonic Development of the Brain
- 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.
- Neurulation is the formation of the neural tube from the ectoderm of the embryo.
- The neural plate folds outwards to form the neural groove.
- Beginning in the future neck region, the neural folds of this groove close to create the neural tube (this form of neurulation is called primary neurulation).
- The hollow interior is called the neural canal.
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Development of Nervous Tissue
- Embryonic neural development includes the birth and differentiation of neurons from stem cell precursors.
- As development proceeds, a fold called the neural groove appears along the midline.
- At this point the future CNS appears as a cylindrical structure called the neural tube, whereas the future PNS appears as two strips of tissue called the neural crest, running lengthwise above the neural tube.
- The sequence of stages from neural plate to neural tube and neural crest is known as neurulation.
- Induction of neural tissues causes formation of neural precursor cells, called neuroblasts.
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White Matter of the Cerebrum
- Superior to the brainstem, such tracts form a broad, dense sheet called the internal capsule between the thalamus and basal nuclei, then radiate in a diverging, fanlike array to specific areas of the cortex.
- The corpus callosum (Latin: "tough body"), also known as the colossal commissure, is a wide, flat bundle of neural fibers beneath the cortex in the eutherian brain at the longitudinal fissure.
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Functions of the Cerebellum in Integrating Movements
- This feedforward mode of operation means that the cerebellum, in contrast to the cerebral cortex, cannot generate self-sustaining patterns of neural activity.