Power is not everything. If it costs too much, too few may wield it. And if it restricts freedom, it will only be tolerated for so long. This is especially true in the years-old competition between lasers and LEDs. These photonics technologies have vied to be light sources in many applications, and brain research is emerging to be a major battleground for them. Over the years, LEDs have relied on their low price to make up for their lack of power, which is lasers’ forte. While LEDs’ low cost has gotten them far and their power is increasing, it has not come far enough to oust lasers in fields such as optogenetics and diagnostics, particularly when it’s acceptable for test subjects to be restrained. However, as two feature articles in this month’s issue highlight, the introduction of portability, namely in the form of test subjects’ ability to freely move around, could help balance LEDs’ power-price dynamic. In “LEDs and Lasers Battle for Dominance in Brain Research,” (read article), contributing editor Marie Freebody examines how LEDs are gaining ground in optogenetics not only because they are cheap but also because of their flexibility. LEDs can be implanted into tissue and their light delivery can be wirelessly controlled, enabling the observation of neural circuits of freely moving and interacting mice. Similarly, Arthur DiMartino of TechEn in “Near-Infrared Spectroscopy: Delving Deeper in the Brain,” (read article), describes how LEDs are driving down the costs of near-infrared spectroscopy (NIRS) brain monitoring systems while also advancing researchers’ understanding of seniors’ and children’s cognition, and mobility of children through the use of wireless NIRS headbands. With these trends, in part spurred by LEDs, he says, “From daily fitness monitors to continuous medical brain monitors, NIRS technology in everyday devices will matter, and will be transformative for years to come.” Other articles in this issue include: • “Nonlinear Microscopy Moves Into the Operating Room,” by Thomas Hellerer, Christoph Polzer and Mojtaba Mohseni at the Munich University of Applied Sciences, (read article); and • “Swept Source OCT Takes Optical Medical Imaging to the Next Level,” by Wolfgang Drexler at the Medical University of Vienna, and Michael Minneman and Jason Ensher of Insight Photonic Solutions, (read article). We hope that you enjoy this issue.