MIT engineers have shone a new light on brain research, quite literally. A team of researchers at MIT has developed a way to detect bioluminescence deep in the brain, using a technique reported to offer a detailed look at the organ's inner machinations. The breakthrough method was detailed in a recent report by MIT News and involves genetically modified blood vessels that respond to light, with their reaction captured through magnetic resonance imaging (MRI).
The innovation addresses a longstanding challenge in neuroscience. The application of optical tools for imaging deep brain structures has been limited due to light scattering before detection can occur. As explained by Alan Jasanoff, a professor at MIT, "A well-known problem that we face in neuroscience, as well as other fields, is that it’s very difficult to use optical tools in deep tissue." According to the study, the technique, called bioluminescence imaging using hemodynamics, or BLUsH, could pave the way for new research into changes in gene expression, cellular communication, and brain's developmental processes, as reported by MIT News.
Traditional methods to track biological processes involve fluorescent proteins; however, their effectiveness is reduced when trying to visualize areas buried within the brain's complex tissue. The MIT team's method subverts this issue by engineering the brain's blood vessels to dilate in the presence of light and then capturing the event with an MRI, exploiting the contrast created by changing blood flow.
Jasanoff's team used a protein called Beggiatoa photoactivated adenylate cyclase (bPAC) which triggers blood vessel dilation in the presence of blue light. This dilation changes the ratio of oxygenated to deoxygenated blood, which has different magnetic properties detectable by MRI scanners. "Blood vessels form a network in the brain that is extremely dense. Every cell in the brain is within a couple dozen microns of a blood vessel,” Jasanoff said in a statement by MIT News. The researchers believe this technology essentially turns the vasculature of the brain into a "three-dimensional camera."
The team conducted their research on rats using a viral vector to deliver bPAC to blood vessel cells, sensitizing a large area of the brain to light. The rats' brain cells were engineered to express luciferase, a light-producing enzyme, when a specific substrate was introduced. Resulting MRI scans revealed glowing brain regions, validating the method's efficacy.
While initial experiments have been performed in rats, the researchers aim to adapt the technique for use in other animal models. Their findings, offering a window into the normally opaque workings of the brain, have generated significant interest in the scientific community. This research was supported by a slew of prestigious fellowships and grants, reflecting the potential this illuminating new tool has for neuroscience and beyond.
