A non-invasive method has been created by researchers at Stanford University, Palo Alto, through which the change in shapes of the nerve cells can be detected when electric pulse passes through them. The technology allowed the researchers to observe the live activity occurring in the nerves through light-accessible parts, such as the eye. Through this technology, the physicians would significantly monitor the visual functioning at cellular-level.
Whenever an impulse passes through a nerve or nerve fires, a variation in the electrical potential is noticed in the cell. Current techniques through which nerve activity has been monitored are invasive requiring complex methods such as fixing of electrodes near the nerves or insertion of fluorescent markers into the cell. But the new technique recently developed by the Stanford team utilized the side-effect of that voltage variation. The membrane of the nerve cell becomes slightly stiffer for a very short period of time, making the cell’s shape rounder. These variations in cell shape can be captured by interferometric (phase) imaging, which senses minute alterations in the light rays passing through the cell or being reflected back from its outer membrane.
To develop this functional apparatus, the team integrated a powerful camera with an interferometric microscope. The high-speed camera equipped could be able to capture 50,000 frames in a second. The capturing speed is the chief operation because the changes in cell shape are very faint. With the help of high-speed imaging, the scientists combined 50 frames in parts, increasing the signal strength and averaging out the noise.
The scientists tested their method by comparing with the traditional method in laboratory conditions. The scientists used a dish of cells that function similar to neurons. Then, they recorded the measurements through electrodes technique as well as interferometric imaging. The results received from both the techniques were precisely matched.
However, this innovation is a part of a larger program that has been aiming to bring back the vision lost due to some kind of disease or retinal injury.