Our picture of the human brain just got a lot clearer with the development of a new technique that allows scientists to monitor neurons in a live brain for months at a time.

Stanford’s Schnitzer Group devised the new technique to model progressions of brain diseases and neural development, according to lab manager Juergen Jung. The project received funding from the National Institute on Drug Abuse, the National Institute of Neurological Disorders and Stroke, the National Cancer Institute and Mauna Kea Technologies.

To begin the process, scientists implant a tiny glass tube, smaller than a grain of rice in width, into the brain, sealing one end almost completely within the skull. To monitor a specific area of brain tissue, they temporarily insert an endoscope, a thin device use to inspect the interior of an organ or cavity, through the exposed end of the tube. The submerged end then acts as a window from which to view the area with the endoscope. This allows for high precision in monitoring specific areas within the brain, Jung said.

Akin to looking through foggy glasses, the older technique relied on substantially thinning the skull to the point that water immersion of the area would achieve a similar “window effect” when viewed with an endoscope. While the old technique allowed for imaging of a wider parameter, it lacked precision for a follow up on the same area, Jung said.

Additionally, thinning the skull left it vulnerable to infection. Now, by sealing part of the tube within the skull instead, infection is no longer an issue. In fact, the lab found that a cap was unnecessary for the end exposed to the outside of the skull.

“We could just leave it open and blow out any dust before inserting the endoscope for a clear view,” Jung said.

Although the small probe allows for durability and precision, it also limits how much researchers can see.

“You want a tiny probe and a huge field of view,” Jung said. But because the two goals are contradictory, “you must find the right balance and chose parameters accordingly.”

To view a deep brain structure such as the hippocampus, the tube must pass through other brain tissues, specifically the motor cortex. Rather than force the tube through the tissues in implantation, part of the motor cortex must be removed.

In using the tube to study diseases or development, this could pose a problem as removal of the tissue may have an impact on a subject’s cognitive function. But Jung noted, “Usually other parts of the brain will take up the destroyed section’s function.”

The lab used the new technique to monitor the progression of cancer in mice through chronic imaging of red blood cells in capillaries in the affected area of the brain.

In using existing technology of high-speed cameras to make time-lapse movies of single cell movements, the lab was able to measure the speed of blood flow throughout the progression of the disease. The lab supported, with this higher resolution imaging, the previously held belief that blood rate slows as cancer progresses in an affected region.

“This [imaging] could be interesting for pharmaceutical companies,” Jung said. “For example, if you have a medication, what kind of [visible] impact does it have?”

Company researchers would need to determine where to image and how to access the area. This specificity requires designing the endoscope and glass tube exclusively for each medication and affected area to be observed.

While the technique is now being integrated into neurological research with animal models, the Schnitzer Group also wants to get the technology into a surgery room, Jung said.