Beyond LASIK: Transcranial Magnetic Stimulation To Improve How You Process What You See

Transcranial magnetic stimulation might make snipers more accurate.

Transcranial magnetic stimulation might make snipers more accurate.

Photo by PASCAL GUYOT/AFP/Getty Images

A recent study reported in PLoS One indicates that a painless and non-invasive technology called transcranial magnetic stimulation can improve visual perception in healthy people. We’re not talking about improving visual acuity (the functions that are described as 20/20 for physiologically normal eyesight), but the mental process of visual perception that involves noticing something in visual field—and this development may play a role in the future of warfare.

In TMS, a magnetic coil is placed above the head, and electrically produced magnetic pulses pass through the cortex. Depending on the particulars of the electrical signal that generates the magnetism, these pulses can alter the firing rate of certain neurons. All you feel is a tapping on the skull as scalp muscles contract and a popping sound from the magnetic coil.  Researchers hope that TMS may someday be used to treat stroke patients or those with dementias.

In the recent study, scientists directed TMS to areas of the cortex called the frontal eye fields. At the same time, they showed the participants low-contrast images on a laptop with an eye-tracking screen.  The volunteers were to push certain keys on the laptop as soon as they noticed a cross on a target. With TMS, researchers identified temporary improvement in visual sensitivity.  That is, the participants were more likely to notice something on the screen when their brains were being stimulated. In a second experiment, participants were exposed to a flashing black circle just before the target appeared. If the target flashed in the wrong place, the participants did not respond as quickly even with the TMS.

Although the research is intended to determine whether TMS can help people with visual impairments due to cortical injury, it also suggests that healthy people (and their workplaces) could benefit from better-than-normal visual perception. This seems particularly likely to help the military: Soldiers on reconnaissance duty, snipers, or fighter pilots operating in target-rich environment could benefit.

As I discussed in my book Mind Wars, the Defense Advanced Research Projects Agency has given grants to researchers investigating whether neurostimulation can improve impaired cognitive performance and reduce the other effects of sleep deprivation on soldiers, perhaps through helmets that deliver the tiny current. The 2009 NRC report Opportunities in Neuroscience for Future Army Applications lists in-helmet and in-vehicle TMS as long-term projects to keep on the R&D radar. But visual perception would be a new addition to the warfighter-enhancement menu.

In their study, the French, Spanish, and American investigators found that visual sensitivity improved by about 12 percent. That might not seem like a lot, but consider that if you’re in a combat setting that margin might significantly increase your chances of avoiding death or serious injury—and improve your chances of inflicting the same on the other guy.

The finding that visual cues were also helpful when combined with TMS ties in with DARPA’s Cognitive Technology Threat Warning System, which uses EEG to identify visual patterns that the user may not have noticed. The device then alerts the user to attend to a certain part of the visual field that might be of interest.

The new TMS results come from lab studies, not real-world field tests. But even at this early stage, it’s worth considering some of the ramifications of bringing this technology to the battlefield. For instance, how will warfighters to adjust to life without TMS once they leave the warzone?  Could their visual perception be so sharpened that they will be excessively alert to subtle modifications in the visual environment, like combat vets who overreact to loud noises?

Of course, as economies of scale bring widespread access to cognitive enhancers, we may all be so perceptually active that we won’t notice the difference.