Calcium good for more than strong bones.

• Position: Brain Cells

When memories are made and learning occurs, the connections between brain cells change. Scientists know that an influx of calcium is critical to this process. A theoretical model developed by a research team from Brown University, Providence, R.I., shows that cells' ability to fine-tune this calcium flow not only sparks changes in synapses, but allows cells to maintain a working state of equilibrium.

Luk Chong Yeung, a neuroscience research associate, and her colleagues have come up with a concept that hinges on calcium control. Certain receptors, which act like gates, allow calcium to rush into brain cells that receive memory-making information. Once inside these cells, calcium sets off chemical reactions that change the connections between neurons, or synapses. That malleability, known as synaptic plasticity, is believed to be the fundamental basis of memory, learning, and brain development.

Yeung has demonstrated that the control of these receptors not only makes synapses stronger or weaker, but stabilizes them--without interfering with the richness of the cellular response to signals sent from neighboring cells. "The beauty of the brain is that it is plastic and robust at the same time," Yeung explains. "If the model is verified experimentally, we've solved an important piece of the puzzle of how these seemingly antagonistic properties can and, in fact, must coexist in the cell."

Scientists...