One of the concerns the researchers faced when imaging a live animal was how long a correction would persist. In astronomy, stars twinkle so fast that up to a thousand corrections are needed per second. Fortunately, Ji and Betzig learned that, for an anesthetized mouse, a single correction would remain valid for nearly an hour. Another question was whether the correction made at a single guide star bead could be applied to surrounding areas. Although the answer varies from sample to sample, Ji's work has shown that a single correction will often apply to a space of over 100 micrometers in each direction, a volume that can fit dozens of neurons. "It would be prohibitively slow if you had to correct at every point throughout an entire volume," Betzig says. To address this same problem in the field of astronomy, scientists employ a series of deformable mirrors that each look at guide stars in different directions. Betzig hopes to use a similar strategy to widen the correction even further in his microscope.
Since arriving at Janelia Farm in 2005, Betzig and his colleagues have pioneered new super high-resolution imaging techniques and shared them with biologists. One of them, photoactivated localization microscopy or PALM, maps individual protein molecules to produce images with 10-20 times the resolution of a traditional light microscope. PALM and other types of imaging, such as confocal microscopy and wide-field imaging, can be greatly improved with adaptive optics, he says. This is only the beginning. "What we do is primitive compared to the sophistication of what they do in the astronomy community," Betzig says. "I still feel we have a lot to learn f
|Contact: Andrea Widener|
Howard Hughes Medical Institute