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Synaptic pruning is classified separately from the regressive events seen during older ages. While developmental pruning is experience dependent, the deteriorating connections that are synonymous with old age are not. The stereotyped pruning can be compared to the process of chiseling and molding of stone into a statue.
This finding is not as clear though as supporters of adult neurogenesis suggest; the dentate gyrus cells stained with DCX have been shown to have a mature morphology, contrasting the idea that novel neurons are being generated within the adult brain. [17] The role of new neurons in human adult brain function thus remains unclear.
The development of the nervous system in humans, or neural development, or neurodevelopment involves the studies of embryology, developmental biology, and neuroscience.These describe the cellular and molecular mechanisms by which the complex nervous system forms in humans, develops during prenatal development, and continues to develop postnatally.
It is hypothesized in [66] that the growing structure copies the axonal development of the human brain: the earliest developing connections (axonal fibers) are common at most of the subjects, and the subsequently developing connections have larger and larger variance, because their variances are accumulated in the process of axonal development.
Guillain–Barré syndrome – nerve damage. Neuroregeneration in the peripheral nervous system (PNS) occurs to a significant degree. [5] [6] After an injury to the axon, peripheral neurons activate a variety of signaling pathways which turn on pro-growth genes, leading to reformation of a functional growth cone and regeneration.
These organisms can represent a model for the genetic analysis of adult neurogenesis and brain regeneration. There has been research that discuss how the study of “damage-responsive progenitor cells” in Drosophila can help to identify regenerative neurogenesis and how to find new ways to increase brain rebuilding.
For example, motor neurons, which travel from the spinal cord to the muscle, can have axons up to a meter in length in humans. The longest axon in the human body belongs to the Sciatic Nerve and runs from the great toe to the base of the spinal cord. These are archetypal examples of neural pathways. [citation needed]
For instance, brain-derived neurotrophic factor (BDNF) is produced by the brain and regulates several functions within the developing synapse, including enhancement of transmitter release, increased concentration of vesicles, and cholesterol biosynthesis. Cholesterol is essential to synaptogenesis because the lipid rafts that it forms provide a ...