TechKnow: How do you plan on measuring your progress with the tDCS headset?
Erica: So I’m using a brain training game called Dual N-Back. So far I’ve tracked my progress with the game without using the tDCS, and I plan to use tDCS, and then practice the game and see how far I can get.
TechKnow: Are you going to record this information? Do you plan on making it available to other people?
Erica: I plan to track the amount of time I’m spending using tDCS and how well I’m performing in the game to see what is correlated.
I could do without all the electroshock cutaways. Interesting that the same protocol & montage that so improved the Radiolab reporter’s results with the stereograms did nothing for this reporter. The reverse-polartiy montage did however seem to have quite an effect on producer Justin. Both these montages are discussed in my interview with Michael Weisend.
My sense is that the author’s experience is very similar to that of most tDCS DIYers – an initial flurry of interest followed by frustration at not knowing if ‘it’s working’. That’s why it’s exciting to see easily replicated protocols for self-testing emerging around the Dual N-Back game that is available for free. http://brainworkshop.sourceforge.net/download.html
We’d decided to try the “accelerated learning” montage that had been developed and tested by DARPA. The best test of the device we could come up with was to play Nintendo Wii Mario Kart while brain zapping for 20 minutes — our performance seemed easily measurable (we would just play the same course, over and over) and a lot less violent. At first I was miserable, my green dinosaur avatar, Yoshi, falling off the track on every hairpin turn and barely finishing the course in 3:30. By the end, though, I was cracking 3:00. Of course, there was no control here, no way to tell whether I was simply learning a new skill, but I was cautiously optimistic.
In the weeks that followed, I stuck to it, undertaking 20 minutes of tDCS four to five days a week. I decided to try to teach myself interactive web design, and whenever I’d run the current through my brain, I’d accompany it with 20 minutes on Code Academy, the teach-yourself-to-code megasite. But after a few weeks, the results I was looking for seemed elusive. I was obviously getting better at coding, but there was no way for me to know what role the electricity was playing. And it was still kind of painful. So I quit, and about two months after visiting Bikson’s lab, my tDCS device is gathering dust on a shelf in my office.
tDCS has so many promising applications – what excites you the most?
I’m personally most excited about the promise tDCS seems to hold for individuals with Major Depressive Disorder. Although the paradigm may be more complicated (what exactly is a behavioral treatment for depression?), if it has even a minor effect, it could help millions of people.
I have dealt with depression since I was a child. I see a therapist weekly and take a daily dose of citalopram, a selective serotonin reuptake inhibitor. I’m lucky that I’ve found a drug that works for me. Many people are not. They struggle to find an appropriate dose or maintain a drug after its effects change with time. If this proves to be a reliable alternative treatment, it could be a real game-changer.
At the end of the stimulation period we found a significant beneficial effect of A-tDCS as compared to baseline and S-tDCS in all our subjects, regardless of word difficulty, although with some inter-individual differences. In the follow-up period, the percentage of correct responses persisted significantly better until the 16th week, when an initial decline in naming performance was observed. Up to the 21st week, the number of correct responses, though no longer significant, was still above the baseline level. These results in a small group of aphasic patients suggest a long-term beneficial effect of on-line A-tDCS.
Interesting especially in relation to Michael Weisend’s success using F10 in skill (target recognition) acquisition. That the research is going in this direction is encouraging. I expect we’ll have a much better understanding of various cognitive enhancement strategies over the next few years.
We compared effects of 30 min prefrontal and parietal stimulation to right and left hemispheres on subtask performance during the first 45 min of training. The strongest effects both overall and for ship flying control and velocity subtasks were seen with a right parietal C4, reference to left shoulder montage, shown by modeling to induce an electric field that includes nodes in both dorsal and ventral attention networks. This is consistent with the re-orienting hypothesis that the ventral attention network is activated along with the dorsal attention network if a new, task-relevant event occurs while visuospatial attention is focused Corbetta et al., 2008. No effects were seen with anodes over sites that stimulated only dorsal C3 or only ventral F10 attention networks. The speed subtask update memory for symbols benefited from an F9 anode over left prefrontal cortex. These results argue for development of tDCS as a training aid in real world settings where multi-tasking is critical.
Tinnitus is the perception of a sound in the absence of an external auditory stimulus and affects 10–15% of the Western population. Previous studies have demonstrated the therapeutic effect of anodal transcranial direct current stimulation tDCS over the left auditory cortex on tinnitus loudness, but the effect of this presumed excitatory stimulation contradicts with the underlying pathophysiological model of tinnitus. Therefore, we included 175 patients with chronic tinnitus to study polarity specific effects of a single tDCS session over the auditory cortex 39 anodal, 136 cathodal. To assess the effect of treatment, we used the numeric rating scale for tinnitus loudness and annoyance. Statistical analysis demonstrated a significant main effect for tinnitus loudness and annoyance, but for tinnitus annoyance anodal stimulation has a significantly more pronounced effect than cathodal stimulation. We hypothesize that the suppressive effect of tDCS on tinnitus loudness may be attributed to a disrupting effect of ongoing neural hyperactivity, independent of the inhibitory or excitatory effects and that the reduction of annoyance may be induced by influencing adjacent or functionally connected brain areas involved in the tinnitus related distress network. Further research is required to explain why only anodal stimulation has a suppressive effect on tinnitus annoyance.
So, using tDCS, McKinley’s lab kept 30 people up for 30 hours to see how they fared with and without fatigue interventions. Essentially, they compared the effects of 200 mg of caffeine (about equal to 2 cups of coffee) to 30 minutes of tDCS at two milliamps (mA) applied to an area of the brain called the dorsolateral pre-frontal cortex, which is very important for the cognitive processes of attention and vigilance. The results suggest that applying electricity to a brain for half an hour is more effective than consuming something caffeinated.
Specifically, the people who were electrically stimulated were more vigilant for longer than those given caffeine — up to six hours versus two. Previous studies found that a shorter duration of tDCS could modulate vigilance for 30 to 90 minutes, which is within the range of the two hours of caffeine action. This time, said McKinley with excitement, “we recorded 6 hours after we gave the stimulation. This time it was 30 minutes of stimulation, and we did not see the performance taper off… there’s got to be a point where it drops off again, we just haven’t reached that… We were very surprised that 6 hours later it was still working… exciting, but also a little baffling.”
Mike Day undergoes physiological testing during Red Bull Project Endurance. Fellow participant Jesse Thomas said the week was “intense, painful, limit pushing, and shocking…literally.” Photo: Michael Darter/Red Bull
Though TMS not tDCS, it would be interesting to see the original paper (paywall). My understanding is that the hippocampus is a difficult target for tDCS. But perhaps insights from this study could lead to ideas for a ‘memory enhancing’ tDCS montage.
To test this, Voss and his team of researchers had 16 healthy adults between the ages of 21 and 40 undergo MRIs so the researchers could learn the participants’ brain structures. Then, the participants took a memory test which consisted of random associations between words and images that they were asked to remember. Then, the participants underwent brain stimulation with TMS for 20 minutes a day for five days in a row. TMS uses magnetic pulses to stimulate areas of the brain. It doesn’t typically hurt, and has been described by some as a light knocking sensation. The researchers stimulated the regions of the brain involved in the memory network.
Throughout the five days, the participants were tested on recall after the stimulation and underwent more MRIs. The participants also underwent a faked placebo procedure. The results showed that after about three days, the stimulation resulted in improved memory, and they got about 30% more associations right with stimulation than without. Not only that, but the MRIs showed that the brain regions became more synchronized by the TMS.
Felipe Fregni, an associate professor at Harvard Medical School who was involved with the research, has a theory on why that happened. “The students ingested fewer calories because they could make more rational decisions,” he says.
He says tDCS may have dialed up the activity in the students’ prefrontal cortices—where the stimulation was applied and where they make rational, considered decisions, which in turn dialed down the students’ initial knee-jerk reaction to eat food when they saw it. This makes good sense: The dorsolateral prefrontal cortex is known to be an area of the brain that enables us to inhibit temptation.
“It’s the part of the brain most developed in humans compared to monkeys, and it relates to some of the more advanced abilities we have,” says Roi Cohen Kadosh, a neuropsychologist at the University of Oxford who is another of the leading lights in tDCS research. “It’s involved in learning and working memory, and it’s highly connected to other brain regions, such as ones involved with addictions and rewards, and food is rewarding.”
But if a group of neuroscientists who have experience with TDCS built an OpenSource device and explained how to build and use it in a public forum, such as YouTube, then the DIY community would be armed with the necessary knowledge to execute legal, safe, and controlled brain stimulation. This would bypass the necessity of shifting power into the hands of profit-seeking corporations or eavesdropping government agencies, and encourage a self-initiated and self-regulated approach to the direct manipulation of brain states. We manipulate our brain states all the time, actually. This common manipulation is called thinking, and individuals should have as much control of that as possible.