Calcium usually conjures images of strong bones and glasses of milk. Those with a brain injury are often told by their doctors to increase their calcium intake, as low blood calcium often occurs in brain-injury patients. Inside your brain, though, calcium plays a very different role that scientists are learning can turn dangerous after an injury.

Brain cells communicate through tiny gates called calcium channels, which let calcium atoms flow in and out. “Calcium channels are the major determinant of calcium influx,” explains Troy Littleton, a neuroscience professor at Massachusetts Institute of Technology. Following a stroke or head injury, these gates can jam open, flooding cells with calcium and igniting inflammation and cell death.

Recent discoveries, many of which are available to view on the NLM database, spotlight new culprits. In 2026, scientists found that a channel called Orai1 flips the brain’s immune cells into “attack mode”; blocking it in mice calmed inflammation. Another channel, Piezo1, physically senses damage.

Importantly, these new findings confirm that the danger isn’t calcium itself, but the broken channels letting too much rush in.