Researcher Stevan Nikolin watches Amy Corderoy do a complex test of her working memory while receiving tDCS of her brain. Credit:Steven Siewert Nikolin studies brains. In particular the electrical activity that underlies everything they do. While for decades science and medicine have placed their hope in drugs to change the way our brains function, today a growing body of clinicians and researchers are turning to a new hope: electric and magnetic stimulation. The day I put electricity through my brain When I meet Nikolin on a crisp Autumn Friday afternoon, it's probably an understatement to say I'm a little excited to be participating in his clinical trial, after a wave of media coverage of transcranial direct current stimulation (tDCS) that suggests it has some incredible effects on the brains of healthy volunteers like me, let alone the promise it shows for illnesses like depression.

tDCS stimulates the brain using electrodes attached to the outside of the skull that deliver constant, low-dose electrical currents to different parts of the brain. Stevan Nikolin. When I arrive I have to fill in a long survey covering everything from what stage I am at in my menstrual cycle to how much alcohol I consume (I'm pretty sure I underestimated the alcohol) before having my head measured and hooked up to 33 electrodes that should line up to particular regions of my brain. It feels slightly like an exercise in phrenology, but Nikolin says it's really the only way to do it without expensive brain scans to find any minor differences between participants' brains. I also have to undertake an incredibly difficult working memory test, called the n-back test. In the n-back I'm presented with a series of letters and I have to press a button every time particular letters are repeated. The brain is a complex network of about 86 billion neurons, cells which send messages by being turned on or off by electrical and chemical signals. Nikolin explains that tDCS is kind of similar to super-charging your brain with a big dose of caffeine – it encourages more of those neurons in the areas being stimulated to be in the "on" position.

Before he turns the machine on I take a practice version of the n-back. I completely panic, bombing out as the letters flash by faster than I'm expecting. By the second, baseline test, which will be included in the study, I'm getting in to the swing of it. Then, it's time to turn the electrodes on. I feel, well … not much. A slight warm tingling, perhaps, kind of like the feeling you get on your skull if you bleach your hair. The feeling not much is happening is compounded through two more n-back tests, the first while being stimulated and another after, which seem just as hard as ever. Should you believe the hype?

Honestly, I don't quite know what all the fuss is about. tDCS has become legendary within the online world, with countless websites and threads explaining how to build your own machine and groups springing up world-wide using it to try and improve their performance in everything from tests, to chess to video games. Nikolin says it's hard to know how much is hype. "If someone plays chess every day while they are using tDCS, is it the stimulation that's making them improve, or have they just been playing chess every day?" And there's another concern. While single doses of electro-stimulation are thought to be safe, daily or weekly doses at varying levels are relatively untested. "The way tDCS works is it's sort of like a rudder on a huge, huge oil tanker, and every session you make these tiny fractional changes to the direction of the oil tanker, and maybe over a very long time you can start to see an effect on this huge ship," he says. "At some point you may find you have set a course that might be a bit dangerous."

And therein lies the problem: no-one totally knows how tDCS and other brain stimulation really works. In fact, that's what Nikolin is trying to figure out with his study. "tDCS came about a few decades ago, and initially, the very first way it was applied … was just electric eels on people's heads, and they found they seemed to get a benefit in mood. So we are working backwards in a way, figuring out how it happens and making changes, without understanding the mechanisms underneath those changes," he says. "Unless you know exactly what's going on, you are sort of shooting in the dark, and any progress essentially happens on a hunch or a process of elimination." So while there is hope that brain stimulation will give treatments that were in the past promised by drug development, many of these treatments are still being developed in a similar manner to drugs. "Most of the drugs we use today were completely serendipitous," Nikolin says. "Pharmaceutical companies essentially have huge operations that pump out variations on different compounds, and they essentially feed them to people to see what happens."

Add to that the incredible complexity of the brain, and the fact it is constantly changing and rewiring in response to our experiences in the world, and understanding something that sounds simple – our memory skills, or feelings of sadness – becomes incredibly difficult. Treatment for public patients held back by funding But Paul Fitzgerald, the deputy director of the Monash Alfred Psychiatry Research Centre, says while it's reasonable to worry about how the complexity of human experience could be whittled down into individual neurons firing, the emerging field has far more brain-based evidence supporting it. The day before we speak he treated 16 patients with transcranial magnetic stimulation (TMS), a more targeted form of stimulation that uses magnetic fields. Two years ago the Royal Australian and New Zealand College of Psychiatrists formally recommended that TMS should be offered to some patients with treatment-resistant depression, but as yet the government has not fundeddelivery through Medicare, so it is usually only given in the private system.

"We used to think that depression was just not enough serotonin in the brain, and so we developed drugs to increase serotonin, but we know that's not an accurate model," Fitzgerald says. "What's actually going on is there are multiple brain regions that are abnormally active, some regions that are over-active, some that are under-active, and these nodes are in a sort of complex network that gives us the possibility of trying to intervene with brain stimulation techniques that can try to … increase brain activity or decrease brain activity in a local way." Fitzgerald says the hope is that more personalised versions of brain stimulation can be developed, that can fine-tune the stimulation to individual people's brains. So what about my brain? "I'm sure I was in the placebo group," I tell Nikolin. But he says afterwards I wasn't, even though the sham version would have felt exactly the same. In fact, the tDCS improved my performance on the working memory task by about 20 per cent. Perhaps there's hope for me too, after all.