Researchers have developed a new MRI sensor method for imaging calcium activity in brain cells, allowing them to look much deeper into the brain. They can use this technique to track signaling processes inside the neurons of living animals. It allows them to connect neural activity to behaviors and study brain development and behavior.
The first MRI-based detection of intracellular calcium signaling is analogous to powerful optical approaches widely used in neuroscience. Still, it is possible to perform such measurements in vivo in deep tissue.
The team used MRI to accomplish this, a noninvasive technique that detects magnetic interactions between an injected contrast agent and water molecules inside cells.
The researchers used building blocks that can pass through the cell membrane to create their new intracellular calcium sensors. The researchers put their sensor to the test in rats by injecting it into the striatum, a brain region involved in movement planning and learning new behaviors. They measured calcium levels in neurons by stimulating electrical activity with potassium ions.
This MRI sensor technique can identify small clusters of neurons involved in specific behaviors or actions. Because this method directly measures signaling within cells, it can provide much more precise information about neuron activity location and timing than traditional functional MRI (fMRI), which measures blood flow in the brain.