A team of neuroscientists and bioengineers at the University of Colorado have created a miniature, fiber-optic microscope designed to peer deeply inside a living brain. The researchers published details of their revolutionary microscope in the Optics Letters journal. The team state that microscopes currently only penetrate about one millimeter into the brain and almost everything researchers need to see is deeper than that. Now researchers can manipulate this lens while most others are fixed. That means they can see neurons firing inside a living brain.
The novel laser-scanning microscope, a prototype which will be further refined, uses fiber-optics and a tiny electro-wetting lens. Compared to other small, focusing lenses, it’s fast and not sensitive to motion. This allows it to reliably focus on living tissue. At the same time, the lens allows a rapid shifting of focus by applying electricity across two different liquids, which actually changes the curvature of lens.
The microscope, about half an inch in diameter, can be directly mounted onto the head of a mouse. A thin, fiber optic cord will allow the animal to freely roam while scientists look inside its brain and monitor reactions to certain stimuli. That means parts of the living brain like the amygdala, which had been virtually off-limits to microscopes, will soon be seen in real-time, high-resolution, 3-D images.
Using optical methods to stimulate and record from neurons is the future of neuroscience research, state the team. However, most researchers are adapting existing large microscopes to fit mice for head-fixed imaging which limits movement, is difficult to set up and there are existing issues with motion. The researchers found that the solution was to put the microscope on the mouse, rather than putting the mouse on the microscope.
The researchers state that the new microscope opens a new world for scientists, adding that the medical community can now measure a large region and sample more neurons. For example, the team state that the new microscope can image up to 100 neurons at the same time, as opposed to perhaps the 10 or so the medical community could image in real-time in the past.
All of this has potential human applications as well say the team. They go on to add that the ability to see beneath the surface of the brain offers new, powerful ways to study brain function. It will help researchers understand brain disease and formulate new treatments.
The team hypothesize that other uses could include, screening pharmaceuticals targeted to specific brain disorders, allowing neurosurgeons to image small brain areas like those targeted in the treatment of Parkinson’s disease, conducting optical, in situ, biopsies for diagnosis of brain tumours, and examining the connection between neural damage as well as controlling prosthetic limbs. The potential is limitless with these new technology they state.
Source: University of Colorado
