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Neurogenesis refers to the generation of new neurons. These neurons arise from stem cells or progenitor cells during embryonic and early development, it can continue into adulthood in organisms like fishes, amphibia, and insects. The adult mammalian nervous tissue was thought to be incapable of this process, but recent research findings prove this as not true.
Is Neurogenesis True?
Even in adults many tissues could regenerate or replicate themselves, in event of growth or repair, but it was thought that this was not the case for neurons. One of the reasons behind this was the complexity of the structure of neurons; they have cell bodies from which one long axon emerges and there are also dendrites that are highly branched that rise from these cell bodies.
This nerve cell is part of a networking functioning unit that makes its replication a difficult process. Another reason is that damage to the brain or spinal cord causes irreversible damage hinting that there is a lack of neuronal regeneration. Death of neurons with aging showed symptoms of cognitive decline as these cells are not being replaced.
Lab Studies of Neurogenesis
Research lab studies on organisms like shrews and rats demonstrate the significance of neurogenesis. New labeling and imaging techniques aided in proving the fact that new neurons were born also in the adult brain. Environmental processes played a key role to alter neuronal degeneration with age.
Exercises and cognitive processes strengthen and enhance neurogenesis while stress impacted this process negatively. It was discovered in 2005, that older mice who were still active on wheels showed a higher rate of neurogenesis than sedentary mice.
Neurogenesis in Adults
Research on adult hippocampal neurogenesis has revealed significant data on this process. Neuronal regeneration occurs in 2 regions of the adult mammalian brain; one of them is the hippocampus.
This center of memory is found deep in the brain and has a tiny sea horse shape and helps in the processing of short-term memory into long-term memory. It also helps with spatial learning and navigational ability.
The other region is the subventricular zone where neurogenesis can be seen. This region comprises stem cells and progenitor cells. More research is needed to understand what happens to the new neurons formed here.
Some of them migrate to the olfactory bulb, but there is major purpose is still to be discovered. The presence of these progenitor cell-enriched sites may make it easier for neuron generation.
Neurogenesis and Hippocampus
The hippocampus region is susceptible in the early stages of Alzheimer’s disease, which may damage the area and also affect the disease’s progression. Hippocampus is critical for navigation and memory and possible damage may impact their functioning as in Alzheimer’s patients that get lost easily and find it hard to remember things. Besides neurodegenerative diseases, hypoxic conditions may also damage this region.
Such conditions of low oxygen availability can occur during a heart attack, carbon monoxide poisoning, sleep apnea, and other dangerous situations like drowning. Impairment of this region can also cause anterograde amnesia, where the person struggles with making new memories.
How to Enhance Neurogenesis?
Recent research has indicated that neurogenesis does occur in the adult brain. The factors that can potentially increase this process are being investigated. Exercise, sex, intermittent fasting, and learning can increase the neurogenesis rate.
Foods like blueberries and dark chocolate that are rich in flavonoids, omega-3-fatty acids found in fishes like salmon, and resveratrol found in red wine can also enhance this process. Some factors can also decrease neurogenesis like sleep deprivation, stress, alcohol, and diet high in saturated fat.
Thus up to a limit changes in behavior and diet can enhance the rate of neurogenesis. Further research needs to be done to come up with a therapeutic technique for reversing hippocampal damage and damage caused by aging.