Adult neuron formation

Research into brain cell formation could lead to major breakthroughs in psychiatric and other medicine.

It wasn’t long ago we believed human brains could not produce any new cells. Two decades ago, this was the prevailing scientific opinion – all brain cells formed in the womb or shortly after birth.

In recent years, this assumption has been proven wrong as research shows human brains do create new cells even in adulthood. Neurons are formed in a process known as neurogenesis and they function in several key areas of the adult brain including the sub-ventricular zone and the hippocampus.

New cells form and then work to find a place within the existing brain structure by competing with older cells and replacing those that are not functioning as well as they should.

In itself, the discovery that our brains continue to make new cells throughout our lives is groundbreaking. Even more exciting to me are the implications this could have on the future of medicine including psychiatry.

For example, the hippocampus is known to play a key role in memory and has also been implicated in several psychiatric disorders including Alzheimer’s disease, schizophrenia and depression.

Right now studies suggest the presence of neurogenesis in this part of the brain enhances some learning and memory functions while the absence of new cell formation diminishes these functions. Further, environmental stimuli such as stress, drug use or exercise are shown to affect neurogenesis.

Studies to date suggest alterations in neurogenesis could account for the impact of early life events on adult mental health.

One study published in the journal Neuron suggests the continual formation of new brain cells may help give adult brains the same kind of learning ability seen in young people’s brains, while still maintaining the stability of the adult brain.

This study examined neurons at a molecular level and specifically looked at the plasticity of these cells. Young cells are more ‘plastic’ making them more adaptable. As they mature, they become less adaptable. This study found that the plasticity of new adult brain cells was dependent on the function of a receptor associated with learning in newborn animals.

Researchers in this study concluded adult neurogenesis could represent more than simply a replacement mechanism for lost cells, but also an ongoing developmental process giving the mature nervous system expanded adaptability to experience throughout life.

These findings may lead to stem cell based treatments for diseases like multiple sclerosis, Parkinson’s and Alzheimer’s where mature neurons have died and connections are gone. Introducing young neurons into these areas could potentially help upgrade or repair older circuitry.

Studies involving neurogenesis and the antidepressant fluoxetine indicate the drug’s effects may be inhibited if neurogenesis is not taking place. In this instance, the formation of new cells may be needed for the drug to work and may explain why these drugs take several weeks to become effective.

Results like those are encouraging and have widespread implications across medicine. As research continues we will undoubtedly learn more about how the brain works and a variety of possible practical applications for neurogenesis in treatment.

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About the Author

Paul Latimer has over 25 years experience in clinical practice, research, and administration.

After obtaining his medical degree from Queen's University in Kingston, Ontario, he did psychiatric training at Queen's, Oxford and Temple Universities. After his residency he did a doctorate in medical science at McMaster University where he was also a Medical Research Council of Canada Scholar.

Since 1983 he has been practicing psychiatry in Kelowna, BC, where he has held many administrative positions and conducted numerous clinical trials.

He has published many scientific papers and one book on the psychophysiology of the functional bowel disorders.

He is an avid photographer, skier and outdoorsman.

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The views expressed are strictly those of the author and not necessarily those of Castanet. Castanet does not warrant the contents.

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