November 12, 2012

When you were still developing, your brain was an overachiever just like that straight-A class president with perfect teeth and a canned food drive. Your brain overproduced neurons, then later paired down the neuron population to fine-tune development and function. Today’s image is from a paper that describes this process and the regulation behind it.
 
Interneurons are neurons that make connections with other neurons, and are found throughout our bodies. In our brain, our cortical neurons are produced far away from their final destination in the fully mature brain. It has been suggested that these neurons are overproduced, and then migrate to the cortex where the excess neurons are eliminated. A recent paper shows this process occurring in developing mice. Southwell and colleagues showed this developmental cell death occurring within the developing mouse brain, within laboratory cultures, and within cortical neurons transplanted into a developing mouse brain. Their results suggest that the cell death is triggered cell-autonomously (from within the cell) or triggered due to competition between other interneurons for survival signals. The image above shows interneuron precursor cells cultured on a plate of cortical feeder layers containing neurons (green), astrocytes (red), and oligodendrocytes (white). About 30% of the cortical interneurons cultured on these feeder layers later underwent cell death.

Southwell, D., Paredes, M., Galvao, R., Jones, D., Froemke, R., Sebe, J., Alfaro-Cervello, C., Tang, Y., Garcia-Verdugo, J., Rubenstein, J., Baraban, S., & Alvarez-Buylla, A. (2012). Intrinsically determined cell death of developing cortical interneurons Nature, 491 (7422), 109-113 DOI: 10.1038/nature11523
Adapted by permission from Macmillan Publishers Ltd, copyright ©2012