New type of microscope can peer into the brain of a living, moving creature

It’s not every day that scientists invent a whole new type of microscope, but that’s exactly what researchers in Germany have achieved with a new project. A collaboration between Helmholtz Zentrum München, Technical University of Munich, the Department of Nuclear Medicine, and Munich School of Bioengineering, the so-called NeuBtracker is an open source microscope that allows people to observe neuronal activities in the brain of a zebrafish larvae without affecting its behavior.

That’s exciting for scientists who want to better understand the brain because it makes it possible to look at how neurons behave, while at the same time tracking natural behavior. The results could have serious implications for everything from building more brain-like computers to testing out drugs.

“NeuBtracker works by synchronizing two cameras,” Gil Westmeyer, a professor at Helmholtz Zentrum München, told Digital Trends. “One looks at the entire arena in which the larvae are freely swimming and measures the position, speed, velocity, as well as tail and fin movements of the larva; the other camera stays centered on the brain of the zebrafish and provides a magnified view of the fluorescence signals showing the brain activity. This ‘tracking’ of the brain by the fluorescence camera is achieved via a galvanometric mirror system that obtains the information on the position and likely swimming direction of the larva from the first camera. Importantly, NeuBtracker thus works without moving stages, objectives or light beams, which may be perceived by the larvae and perturb their natural behavior.”

Because zebrafish are vertebrates, they share important features with the body plan of humans, although their neuronal circuits are much simpler than our own. That gives researchers the chance to understand how specific sets of stimuli are converted into behaviors by certain neuronal networks in the larval brain. These could be used to extract principles regarding which network architectures and patterns of network activity can support different types of “computation.

Dr. Antonella Lauri

“We hope that the open source instrument NeuBtracker will be applied, adapted, and improved by other laboratories in the world to study these fundamental research questions by enabling simultaneous neuro and behavioral imaging across the entire nervous system in an intact organism,” Westmeyer continued. “Another more applied line of research that NeuBtracker empowers is to screen for the combined effects of pharmacological compounds on the behavior and brain activity simultaneously. Since zebrafish larvae are swimming in water, such screens can be conducted very efficiently and can provide important filters and initial hypotheses on which compounds may have desired neuroactive effects that could be further tested for future medical applications.”

A paper describing the work was recently published in the journal Nature Methods.