The Best Thing Since Sliced Bread?
Zebrafish Study Reveals First Fine Structure of a Complete Vertebrate Brain
May 10, 2017
Zebrafish larva head in cross-section. Note this isn’t a single electron microscope image, but many thousands of slices seen on edge. The large black circle is the eye, the big darker gray shape at top the brain. You can also see the nose (black crescent at right), the ear (black crescent near center) and several vertebrae (center bottom).
Why It’s Important
Every thought, every feeling, every sensation—and every behavioral illness—ultimately depends on how our brains work. Despite decades of stunning advances in imaging the brain and measuring its activity, though, we still don’t understand how even a simple vertebrate brain works.
Enter the zebrafish larva. Small and transparent—yet able to swim freely and even hunt small prey—these baby fish have long been studied by researchers to understand how their tiny brains generate behaviors. David Hildebrand, working in
the laboratories of Florian Engert and Jeff Lichtman at Harvard University, took this work a step farther, creating electron microscopic images of the zebrafish brain cut
into tens of thousands of slices.
With the help of co-author PSC’s Art Wetzel, they led an international collaboration that used these images to reconstruct specific nerve cells that spanned nearly the entire larval zebrafish brain. The hope is that this kind of thorough “nano-scale” imaging will make it possible to
extract the brain’s complete “wiring diagram.” While this work has only just begun, it may eventually shed new light on past studies of zebrafish behavior—and point the way toward a better understanding of more complex brains, such as ours.