For analyzing much larger data sets, tools such as Thunder are not just helpful, they are essential, the scientists say. This is true for the information collected by the new microscope that Ahrens and colleagues developed for monitoring whole-brain activity in response to visual stimuli.
Last year, Ahrens and Janelia group leader Phillip Keller used high-speed light-sheet imaging to engineer a microscope that captures neuronal activity cell by cell across nearly the entire brain of an immature zebrafish. That microscope produced stunning images of neurons in the zebrafish brain firing while the fish was inactive. But Ahrens wanted to use the technology to study the brain's activity in more complex situations. Now, the team has combined their original technology with a virtual-reality swim simulator that Ahrens previously developed to provide fish with visual feedback that simulates movement.
In a light sheet microscope, a sheet of laser light scans across a sample, illuminating a thin section at a time. To enable a fish in the microscope to see and respond to its virtual-reality environment, Ahrens' team needed to protect its eyes. So they programmed the laser to quickly shut off when its light sheet approaches the eye and restart once the area is cleared. Then they introduced a second laser that scans the sample from a different angle to ensure that the region of the brain behind the eyes is imaged. Together, the two lasers image the brain with nearly complete coverage without interfering with the animal's vision.
Combining these two technologies lets Ahrens monitor activity throughout the brain as a fish adjusts its behavior based on the sensory information it receives. The technique generates about a terabyte of data in an hour presenting a data analysis challenge that helped motivate the development of Thunder. When Freeman and Ahrens applied their new tools to the data, patterns quickly emerged. As examples,
|Contact: Jim Keeley|
Howard Hughes Medical Institute