When a nerve cell receives a message from a neighboring neuron, a wave of calcium ions rushes into the cell to keep the signal moving. Scientists at Janelia Farm Research Campus have created a new molecular sensor that glows each time it detects one of these calcium waves. By following the flashes of light, researchers can watch as a message gets passed from neuron to neuron throughout the brain.
Calcium sensors for brain activity have been around for about two decades, but earlier versions were less accurate or more cumbersome to use. “You can think of the brain as an orchestra with each different neuron type playing a different part,” says Janelia Lab Head Karel Svoboda. “Previous methods only let us hear a tiny fraction of the melodies. Now we can hear more of the symphony at once.”
|Neurons in the primary motor cortex that express the indicator GCaMP3 light up as they fire in sequence as the mouse moves a single whisker.|
Svoboda, along with Janelia Lab Heads Loren Looger, Vivek Jayaraman, and Rex Kerr, created a sensor named GCaMP6. It is the most sensitive calcium sensor ever developed, and the first sensor that can detect impulses in every neuron in the brain, according to their report in the July 18, 2013, issue of Nature. The team continues to tinker with the sensor and develop new versions for specific uses, including sensors that emit different wavelengths of light so they are easier to detect.
|Learn more about the Genetically-Encoded Neuronal Indicator and Effector (GENIE) Project and the group that created GCaMP6 .|