Previously, researchers believed that as they get older, the brain stops producing new cells, making it much more difficult for adults to master new skills or learn a foreign language.
Later studies found that if specific areas of the brain are hyperstimulated, new cells can form in different areas of the brain, as was shown in the case of London taxi drivers, who were found to have an increase in the number of neurons in areas associated with memorizing maps of the area.
Recent research has shown that new brain cells are actually being formed all the time in different parts of the brain, even in older people. This suggests that the mental and memory problems associated with old age are not limited to the loss of neurons, but rather to the failure of cells to communicate with each other.
In the study, neuroscientists at Columbia University in New York studied the hippocampus of 28 healthy people, ages 14 to 79, who died suddenly. None of them suffered from cognitive impairment or depression, which could affect the development of brain cells. The subject of the study was newly formed neurons and the state of blood vessels in the human hippocampus shortly after death.
Scientists have found that even in the oldest brains, new brain cells continued to form until death. All subjects, regardless of age, had similar numbers of intermediate neuronal precursors and thousands of immature neurons. However, in the brains of the elderly, fewer new blood vessels were formed in the structures of the brain and they encompassed a smaller pool of progenitor cells - the descendants of stem cells, which then turn into neurons.
Scientists have suggested that the deterioration of the brain in old age may be caused by fewer neural stem cells, a decrease in the number of blood vessels, and decreased connections between cells within the hippocampus. The researchers believe that ongoing hippocampal neurogenesis maintains specific cognitive function throughout human life, and that its decline may be associated with impaired cognitive-emotional stability.
This study could help scientists better understand the causes of dementia and how to prevent it from occurring. There are currently about 850,000 people with dementia in Britain, and this figure is expected to rise to 1.2 million by 2025.
The results of the study were published in the journal Cell Stem Cell.
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