Peeking at stem cells in the brain
By Pamela J. Hines, PhD*

For many years, researchers thought the adult brain did not make new neurons - - that we managed through adulthood with only those neurons that survived our youthful exuberance. Some years ago, however, that view was changed with the realization that the adult mammalian brain does indeed have an ongoing supply of fresh brain cells, or neurons, that come from neural stem cells. The new neurons were identified within the olfactory and hippocampal regions of the brain. The olfactory region processes the sense of smell. The hippocampal region remains a bit of a puzzle, although it seems to contribute to memory.

Research reported by Manganas et al.¹ now describes a non-invasive technology for visualizing new neurons in the human brain. The authors used nuclear magnetic resonance (NMR) spectroscopy to identify some compounds characteristic of neural stem cells that could be used as flags. The flags seem to represent a constellation of lipids-- unique to neural stem cells-- for which the specific function remains unknown. The authors then used magnetic resonance spectroscopy (MRS) to follow these flags, and thus ‘see’ the neural stem cells in the brains of living animals.

Although much of this research was sorted out using mouse and rat brains, and cells in tissue culture, the applicability to the human brain was tested as well. MRS, tracking the neural stem cell-specific flags, confirmed the presence of stem cells in the hippocampus of the human brain, and hinted at a decline in neural stem cell activity with age.

The non-invasive aspect of this imaging technology is a particular advantage for its application to understanding the normal aging of the human brain as well as our responses to disease and trauma to the brain. 

*Author Affiliation
Pamela J. Hines, Ph.D.
Senior Editor, Science
American Association for the Advancement of Science
Washington, DC USA

Notes
1. Manganas, L. N., Zhang, X., Li, Y., Hazel, R. D., Smith, S. D., Wagshul, M. E., Henn, F., Benveniste, H., Djuric, P. M., Enikolopov, G., and Maletic-Savatic, M. (2007). Magnetic resonance spectroscopy identifies neural progenitor cells in the live human brain. Science 318, 980-985.

Posted March 21, 2008