The Effects of Neurogenesis on Human Quality of Life

While some may say science does not have the right to manipulate human health, neurogenesis may increase the quality of life in humans. Until recently, neuroscientists believed the central nervous system, including the brain, was incapable of neurogenesis and unable to regenerate. Now, scientists know that neural stem cells are created through neurogenesis, which are able to become a variety of specialized cells in order to fight illnesses. Stem cells, which may be beneficial in fighting off genetic diseases such as cancer, may be created through planned neurogenesis.

Mental Health and Neurogenesis in Early-Life

Several neurogenesis experiments have been conducted on animals. In animal models, it has been found that stress occurring in early-life increases behaviors suggestive of mental illness in adulthood. This may suggest that early-life stress inhibits the production of new neurons in adulthood. Furthermore, early-life stressors such as infection during pregnancy reduces cell proliferation and neurogenesis in both juvenile and adult offspring. In addition to prenatal stress, maternal separation also decreases the complexity and size of new neurons that are created in adulthood. At this time, it is unclear from animal studies if positive events, or simply the lack of adverse events, during development affect behavior into adulthood and neurogenesis. However, data presents a strong case that negative experiences in early development may inhibit neurogenesis and increase mental illness-related behaviors in adulthood.

Mental Health and Neurogenesis in Adulthood

Although the effects of stress on adult neurogenesis and proliferation are challenging to comprehend, it appears to be clear that chronic stress can reduce cell proliferation and decrease survival of new neurons. There has been much research on adult neurogenesis in psychiatric disorders, however, it has focused mainly on depression. These studies have found that stress inhibits adult neurogenesis and increases vulnerability to depression. In order to learn more about the causation between neurogenesis and mental illnesses, technology that enables live imaging of neurogenesis may be a beneficial creation.

Neurogenesis and Stem Cells

Degenerative neurological diseases typically consist of deterioration of local neuronal circuitry and progressive degeneration of specific neuronal types. These neurological diseases are fatal and have limited therapeutic options. Therefore, use of neurogenesis to create stem cells may be essential in replacement of degenerated neuron populations. Stem cells have been found to have advantages over other tissues found in the human body, as they can be genetically modified in culture, enriched to more distinct neuronal types prior to transplantation, and expanded.

Physical Activity

Evidence from animal studies has suggested that the reported beneficial effects of exercise on cognitive function may be caused the enhancement in hippocampal neurogenesis. Throughout multiple studies, physical activity has been repeatedly shown to improve cognition and prevent age-related cognitive decline in humans, particularly in those living with neurodegenerative diseases. A recent meta-analysis study has shown that one to twelve months of exercise in healthy adults brings behavioral benefits such as increases in processing speed, executive function, memory, and attention. Regular engagement in physical exercise in midlife is associated with decreased risk of dementia-development. This suggests that physical exercise may have preventative effects regarding age-related cognitive decline.

Quality of Life

Marian Diamond’s study in 1964 was conducted on laboratory rats. These rats were divided into two groups: one raised in solitary confinement without outside stimulation, and one raised surrounded with toys and playful activities. The isolated rat group was found to have smaller brains and thinner cerebral cortices. The playful rat group exhibited higher intelligence, had larger brains, and were able to navigate through mazes at a much quicker rate than the previous group. This study found that rats allowed to play had increased levels of brain-derived neutrophic factor (BDNF) in their brains. This factor is essential for maintenance and growth of neuron development. A study by Spalding in 2013 compared the animal study to potential humans, as a human study would be unethical, in that incorporating playful activities into daily life may reduce stress and enhance relationships.

Though neurogenesis remains a controversial topic, research conducted in recent years has shown benefits of neurogenesis potentially delaying Alzheimer’s disease, depression, and other adverse health effects. Perhaps more research in the field of neurogenesis and human quality of life is necessary to advocate for population health and provide community health education. Furthermore, physical exercise conducted to attempt neurogenesis (whether or not neurogenesis is completed) is beneficial for body and mind as well. The knowledge is at the forefront. The only question is, what will be done with the information?

Katie Dailey, Population Health Management, B.S. Missouri Western State University, pursuing Public Health Administration, M.P.S, Fort Hays State University.

References

Callison, K. (2015). PLAY: THE FOUNTAIN OF YOUTH — THE ROLE OF PLAY IN ADULT NEUROGENESIS. US Play Coalition, https://usplaycoalition.org/play-the-fountain-of-youth-the-role-of-play-in-adult-neurogenesis

Sailor, K. A., Ming, G. L., & Song, H. (2006). Neurogenesis as a potential therapeutic strategy for neurodegenerative diseases. Expert opinion on biological therapy, 6(9), 879–890. https://doi.org/10.1517/14712598.6.9.879

Schoenfeld, T., Cameron, H. Adult Neurogenesis and Mental Illness. Neuropsychopharmacol 40, 113–128 (2015). https://doi.org/10.1038/npp.2014.230

Suk-yu Yau, Joana Gil-Mohapel, Brian R. Christie, Kwok-fai So, “Physical Exercise-Induced Adult Neurogenesis: A Good Strategy to Prevent Cognitive Decline in Neurodegenerative Diseases?”, BioMed Research International, vol. 2014, Article ID 403120, 20 pages, 2014. https://doi.org/10.1155/2014/403120