Light Brings New Tools to Old Science

Karen A. Newman, karen.newman@photonics.com

Neuroscience has a very long history, one that by some measures stretches back to thousands of years B.C. Certainly, the need to understand how our brains work, why things sometimes go wrong and, ultimately, how we can fix what is broken makes it a compelling subject.

Some 32,000 neuroscientists are expected to gather this month in New Orleans for the 42nd annual meeting of the Society for Neuroscience. Attendees will have the opportunity to consider the latest research into how the brain weighs complex decisions; the progress being made in treating Alzheimer’s disease, spinal cord and traumatic brain injuries, and much more.

Of course, biophotonics technologies will figure into the conversation. On the agenda is a symposium called “Cracking Neural Codes with Photons: Optogenetics as an Integral Tool for Systems Neuroscience,” chaired by Dr. Mark J. Schnitzer and optogenetics pioneer Dr. Karl Deisseroth. Using light to activate and deactivate neurons, optogenetics presents a powerful new technology for brain research. Managing Editor Laura Marshall will report from the Neuroscience meeting on our Light Matters weekly newscast, and you can be sure that what she learns there will inform our coverage in the coming months.

Optogenetics figures into at least one feature in this issue of BioPhotonics, and you can find a healthy selection of archived articles on the topic at www.photonics.com.

Fiber optics, what news editor Gary Boas calls the “Rodney Dangerfield of the photonics world,” has played an integral role in a number of techniques making significant contributions to neuroscience, including BOLD fMRI (blood-oxygenation-level-dependent functional MRI) and optogenetics. In “Fiber Optics Revolutionizes Neuroscience,” beginning on page 20, he examines the importance of fiber optics in the development and application of these two techniques.

Also in this issue, we welcome the first BioPhotonics article from freelance science writer Valerie C. Coffey who tells us that, with increasing frequency, noninvasive, label-free microscopy methods are capturing subcellular details in live cells and tissues at ever-smaller resolutions. In her article, “Optical Microscopy Quantifies Live Cells Without Labels” she writes that several novel label-free methods help biologists to measure quantitative properties and dynamic processes without damaging the live cells. One approach, quantitative phase imaging, records the phase of light as it passes through a transparent or translucent object. Because this technique provides a quantitative measurement of the optical field, dyes and labels are not required to enhance the image contrast. You will find her feature beginning on page 24.

Zhun Xu and Jay Zhao of MicroPhotoAcoustics Inc. describe how switching from optical resolution to acoustic resolution allows scientists to extract more information from samples. In their article, “Flexibility Improves Photoacoustic Microscopy,” the researchers tell us that noninvasive functionality, relatively deep penetration and multiscale spatial resolution make photoacoustic imaging ideal for biomedical applications at various scales, from centimeter-size breast tumors down to micrometer-size red blood cells. You can find their article beginning on page 28.

Finally, who hasn’t watched with fascination as a bruise on the shin changes colors, sometimes rather dramatically, in the days after making contact with a desk or other obstacle. Scientists have wondered whether changes in bruise color could help doctors draw conclusions about when an injury occurred. Dr. Barbara Stam, Dr. Gerhard Holst and Ursula Buczek are three who believe it can. In their article, “Tell-Tale Color Changes: Camera Can Find Age of a Bruise,” the authors report that a reliable method of calculating the specific moment of injury may be available in the near future, thanks to development of a model linking the color of the hematoma to its age, enabling calculation of when the injury originally occurred. You can find their article beginning on page 31.

Enjoy the issue, and let us know what you think. Write to me at karen.newman@photonics.com .