Tyler Beede, at least, is a believer. Watching a promotional video in which the Giants' top pitching prospect hurls pitch after pitch while wearing a set of headphones, you'd think he was listening to tunes. But he's not -- instead, he's getting the juice, tDCS-style.

“It’s a very unique feeling," Beede explains in the video. "You put it on, and it does have that kind of tickling, zapping feeling on your brain, but that’s kind of the reason you know its working.”

Beede, currently playing for the Giants' Sacramento AAA team, credits his improved pitching in 2016 at least in part to the technology.

Tech Central

The headphones, from Halo Neuroscience, are just the latest health tech the team has sampled. Being in San Francisco, digital health startups frequently approach the club in hopes of getting a major league tryout, and Halo is located just blocks from the Giants' AT&T Park.

Head says his role as sports scientist is to "weed through" a lot of the gadgets that companies send the team's way. Plenty of them, says Head, "overpromise and underdeliver."

But Head decided to try the headset, called Halo Sport, during spring training last year—he gave them to some minor leaguers to wear as they sprinted 20-yard dashes. After two weeks, Head analyzed the results and found that the players who wore the equipment had shaved off a few one-hundredths of a second compared to a control group.



In the promotional video, Beede says, "Your brain just becomes so in tune with what you’ve been doing that it can memorize your movements to help you go to that next level."

Targeting the Motor Cortex

Using Halo's headset is kind of like plugging your brain into a 9-volt battery, giving your neurons a little extra jolt and priming them for action.

'Brain stimulation has been around since recorded history. They used to use electric fish to help migraines or gout or some other problems in ancient Egypt.’ Theodore Zanto, UCSF neuroscientist

The earphones are actually just for show, allowing the wearer to use the technology "without necessarily displaying it to the world," a spokesperson for Halo said. The electrodes in the $750 headset are hidden inside the band that connects the earphones. The electrodes target the motor cortex, which is the region of the brain located across the top of your head, spanning ear to ear. The motor cortex sends electrical signals from your neurons to targeted groups of muscle fibers, causing them to contract.

“People like to say that electricity is the currency of the brain and that in many ways the brain is a circuit," says Marom Bikson, a professor of biomedical engineering at City College of New York. "So when we apply electricity to the brain, we interact with that circuit, and we can change how that circuit works."

Theodore Zanto, director of the Neuroscape Neuroscience Research Program at UCSF, thinks applying electricity to the motor cortex enables it to "trigger the 'execute movement' signal faster," he says.

Wiring the brain received a pretty bad rap last century when electroconvulsive therapy was used to deliberately induce brain seizures in order to treat mental illness.

But tDCS uses a very low-voltage electrical charge. Researchers say the major concerns are minor burns, itching, fatigue and nausea. Most of the known injuries have occurred in the the do-it-yourself community, from people who constructed homemade tDCS headsets after watching YouTube tutorials.

Jury's Still Out

Even though companies like Halo, Thync and Focus promise their brain-boosting headsets will reduce fatigue, sharpen focus and improve muscle endurance, experts are cautious.

More than a thousand peer-reviewed studies have looked at how a mild brain jolt from electricity improves everything from physical actions to memory to creativity, and the results are highly inconsistent.

“One of the reasons why we believe the effects are highly variable is because everyone has slightly different thicknesses of scalp, thicknesses of skull, different amounts of cerebrospinal fluid, and that’s what the current has to travel through before it even gets to the brain," says Zanto. He also says age, gender, ethnicity and illness can influence results.

Bikson says marketing claims about tDCS often exaggerate the results from lab studies. For example, researchers may measure how fast someone can press a sensor with their finger before and after wearing a tDCS device.

"And we may see a positive effect," says Bikson. "But that is a world away, though, from a professional basketball player having a marginal improvement in their three-point success percentage after tDCS."

Even though a lot of the data is conflicting, the most positive results do support using tDCS to improve motor control. Hence the slew of startups targeting athletes.

The Giants' Head says even a tiny advantage can help win games at the major league level. An improvement of two-hundredths of a second can be "the difference between safe and out sometimes," he says.

'This is My Brain on Fire'

At a Mountain View gym recently, Emily Hu, a world record holder in power lifting, tightened her silent black Halo headphones before sliding underneath a bar to bench press 220 pounds.

"If I feel the tingling sensation I think, ‘OK. This is my brain on fire," says Hu. "Let’s go!’”

About a year ago she tried stimulating her brain for the first time, while doing squats. Usually she adds just a few pounds to the bar between workouts, but the week she tried tDCS she was able to add nine, peaking at 295 pounds.

“Some people say, 'You know that could have been a fluke because that was only one data point,' " says Hu. " But for me it was a positive enough change that I thought, 'Well, I am going to stick with this device.' ”

Even though Hu hasn’t seen the same kind of improvement every week, she wears the headphones routinely while warming up. “I think it gives me a false sense of confidence to feel the device work,” she says, grinning.

Here to Stay?



Neither Zanto nor Bikson, both academics, are popping tDCS devices onto their own heads -- not to improve athletic performance, anyway. But they both predict the technology is here to stay.

“Brain stimulation has been around since recorded history," says Zanto. "They used to use electric fish to help migraines or gout or some other problems in ancient Egypt."

But the hype around tDCS inspires a lot of new questions. What are the long-term effects of wiring your brain daily? When you zap one part of the brain, are you influencing another region unknowingly, maybe even destructively?

And might using tDCS one day be considered a form of cheating?