Researchers have created a way to use magnetic resonance imaging (MRI) to measure calcium activity in order to analyze signal processing in neuron behavior in living animals, according to a study recently published in Nature Communications.

Calcium analysis can demonstrate critical neuron activity. However, current technology is limited, and can only enter the first few millimeters of the brain’s surface. Researchers at the Massachusetts Institute of Technology have developed an MRI-based intracellular calcium sensor that can penetrate cell membranes. The technique identifies magnetic interactions with a manganese-based contrast agent and water molecules located inside the cells. The system also features a “calcium-binding arm” known as a chelator that binds to the manganese atom when calcium levels are low and releases manganese, which illuminates the contrast agent in the scan.  

The sensor was tested on rats, and the researchers injected it into their striatum, the brain structure associated with motor skills, planning, and execution. They stimulated electrical activity with potassium ions and analyzed the calcium response in those cells.

The researchers hope that the technique could eventually be used to figure “out how different structures in the brain work together to process stimuli or coordinate behavior,” said senior study author and professor of biological engineering, brain and cognitive sciences, and nuclear science and engineering Alan P. Jasanoff, PhD. It could also be used to create diagnostic images of other parts of the body that depend on calcium, such as the heart.