For the Cortex study, Frohlich’s team enrolled 20 healthy adults. Researchers placed electrodes on each side of each participant’s frontal scalp and a third electrode toward the back of the scalp. This way, the 10-Hertz alpha oscillation stimulation for each side of the cortex would be in unison. This is a key difference in Frohlich’s method as compared to other brain stimulation techniques.
Each participant underwent two sessions. During one session, researchers used a 10-Hertz sham stimulation for just five minutes. Participants felt a little tingle at the start of the five minutes. For the next 25 minutes, each participant continued to take the Torrance Test of Creative Thinking, a comprehensive and commonly used test of creativity. In one task, each participant was shown a small fraction of an illustration – sometimes just a bent line on a piece of paper. Participants used the line to complete an illustration, and they wrote a title when they finished.
In the other session each participant underwent the same protocol, except they were stimulated at 10 Hertz for the entire 30 minutes while doing the Torrance test. The tingling sensation only occurred at the start of the stimulation, ensuring that each participant did not know which session was the control session.
Because rating creativity or scoring a test can involve subjectivity, Frohlich sent each participant’s work to the company that created the test. “We didn’t even tell the company what we were doing,” Frohlich said. “We just asked them to score the tests.
”Then Frohlich’s team compared each participant’s creativity score for each session. He found that during the 30-minute stimulation sessions, participants scored an average 7.4 percentage points higher than they did during the control sessions.
Reddit user ADifferentDrum posted the results of his informal long term dual n back/tDCS training research project. Links below to full article.
In an informal experiment aimed at improving memory and attention, I stimulated various regions of my brain using tDCS therapy for 130 sessions over 135 days while simultaneously completing the working memory task dual n back. Each session lasted about 30 minutes. I found that my scores significantly improved both during “live” tDCS treatment and also during intermittent “off” stimulation memory task sessions. I had previously done the dual n back task thousands of trials over the course of two years so the improvement in performance cannot be attributed to practice effects alone. Just as some of the literature suggests, I found that tDCS can improve a very specific skill (in this case “brain game” performance), but the jury is still out as to what benefits, if any does tDCS have in improving other skills outside of training…
Modeling of current flow when applying 1.5 mA tDCS for F4 anodal (top) and P4 anodal (bottom) stimulation and the cathodal electrode placed on the contralateral cheek.
Important study. 72 older participants, average age 64 showed improvement in working memory tasks but also (and this is a big deal where it comes to cognitive enhancement) significant transfer (where improvements are seen in other tasks not specifically trained for). These results run counter to other recent studies and beg the question of whether the participant’s age was a factor. i.e. Is tDCS more effective for aging brains? That would be a big deal. [See Also: tDCS selectively improves working memory in older adults with more education] And thanks to PLOS ONE we can all read the full paper (linked below)
The results demonstrated that all groups benefited from WM training, as expected. However, at follow-up 1-month after training ended, only the participants in the active tDCS groups maintained significant improvement. Importantly, this pattern was observed for both trained and transfer tasks. These results demonstrate that tDCS-linked WM training can provide long-term benefits in maintaining cognitive training benefits and extending them to untrained tasks.
Interesting, the location of the reference (cathodal) electrode was opposite cheek.
In all conditions, one electrode was placed over the target location at either F4 or P4 (International 10–20 EEG system) and the reference electrode was placed on the contralateral cheek.
CC stands for cognitive control. In this study 28 participants took a PASAT test (try one yourself online the better you do the harder it gets). They also reported their state of mind, (PANAS) both before and after the PASAT test. Participants who received tDCS to dlPFC (dorsalateral prefrontal cortext) showed increased cognitive control and less stress from the test itself.
With this study, we provide first evidence that the enhancement of activity in the left prefrontal cortex by anodal tDCS during an adaptively challenging attention task improves performance parallel to, and in correlation with the suppression of specific task-induced negative affect. These data can be interpreted as a tDCS-supported shift of processing resources towards task-oriented performance away from preoccupation with task-related negative affect and cognition. Thereby they extend the notion of enhanced CC by prefrontal activation to internally generated distress-related distractors. More specifically, by demonstrating that tDCS-induced higher performance is associated with a lesser degree of feeling ‘upset’ with the task, these data may exemplify a subjective, experiential aspect of enhanced CC in challenging operations. Not least, these findings substantially support the concept of a tDCS-enhanced CC training as a new pathophysiology-based treatment approach of disorders associated with dysfunctional CC
tDCS seems to be (they say ‘might’), allowing our focus network to overpower the feedback network thereby shutting out the negative feedback (those self-doubting voices).
Since processing in the brain is highly competitive with different pathways mediating different aspects of information, the winners are those with the strongest sources of support . Accordingly, increased activation of the dlPFC by anodal tDCS might strengthen its function to avert attention from affective reactions induced by performance errors and thus maintain goal-directed processing.
BrainSTIM 2015 will be the first ever meeting focused on the combination of brain imaging and stimulation. The meeting will have keynote lectures by leaders in the fields of imaging and stimulation, talks selected from submitted abstracts, educational sessions on integrated brain stimulation and imaging, poster sessions and other opportunities to network. The meeting is designed to inform and educate all who are interested in these topics, from novices to experts. [Get more info]
What a couple of days. First the New Yorker, now PBS tv! If you’re new to tDCS I’d caution you to note that Marom Bikson, one of the leading tDCS researchers in the world, is quoted below as saying ‘perhaps’, as in perhaps it improves brain function. Also, in the section where Andy McKinley is able to dramatically increase reporter Miles O’Brien’s performance of a vigilance task, ask yourself if you really have a need to improve your ‘Where’s Waldo’ score. Unfortunately, the piece doesn’t go into the use of tDCS as a tool to fight depression, which in my opinion, has come closest so far to a verifiable effect borne out by much clinical research. My point is simply that it’s early. We don’t have our tDCS ‘killer app’ yet. Stay tuned!
MILES O’BRIEN: But step aside, grande latte. There’s a new kid on the block.
MAROM BIKSON: So, current is going to come out of the device to the electrodes on your forehead and it’s going to flow through your head.
MILES O’BRIEN: Biomedical engineer Marom Bikson at the City College of New York is prepping me for a dose of transcranial direct current stimulation, or TDCS, a jump-start for my brain.
MAROM BIKSON: It can make the brain perhaps function information more effectively and therefore make you, let’s say, better at things. Or it can make the brain more likely to undergo plasticity, more malleable, more able to learn.
MILES O’BRIEN: A human brain has 100 billion nerve cells or neurons. Neurons are networkers. They make multiple connections with each other via synapses. We have about 100 trillion of them. All of this runs on electricity that we generate ourselves.
MAROM BIKSON: Now, this was the montage that we tried on you.
MILES O’BRIEN: It turns out each of our neurons is a microscopic battery with a-tenth of a volt of electricity. When we’re using them to remember things or do math or write this story, they fire electrical spikes.
MAROM BIKSON: When we’re adding electricity to the brain with TDCS, instead of a tenth of a volt, we’re producing a 1,000th-of-a-volt change, so it’s not enough to trigger a spike. It’s not enough to generate a spike, but it’s enough to modulate the spikes, to maybe get more spikes or to get less spikes.
Fantastic to have a resource in the community like Nathan who has the background and technical expertise to do a deep dive into assessing a device like the new Foc.us v2. The entire review is a must read but here I’m quoting his analysis of the safety issues.
The foc.us also includes some new safety features designed to reduce the risk of high-current-density induced injuries. The most interesting is a soft voltage limit; while the device can technically output voltages out to 60V, users can specify a lower limit to not exceed. This provides protection if the connection between electrodes and the head starts to fail (due to electrode drying or drift, for instance); rather than increase voltage to the absolute maximum in an attempt to drive the target current over the failing connection (which can result in very high current density through a small patch of skin), the device can be configured to simply allow the current to drop using this limit. Unfortunately, there’s no actual alert that the connection is failing (although this can be deduced from looking at the current monitor during operation) but this still provides a good way to avoid many of the safety issues that the high maximum operating voltage would otherwise entail.
Another important area of safety is the ability of the current regulator to maintain its specified current and voltage outputs under varying conditions. Here I tested the device under two conditions: with relatively stable impedance at varying levels (simulating a typical use case in a person sitting still) and in an “impulse” condition, where impedance changes instantly from very high to very low or vice versa. The purpose of this testing method is to measure the device’s response to temporary very sharp changes in impedance caused by disconnection and reconnection of the electrodes as might occur in the Edge device when used during athletic performance.
Here the foc.us performed perfectly; neither current nor voltage ever significantly exceeded their specified maximums under varying conditions. The response to impulses was particularly impressive, with no significant “overshoot” even at the maximum voltage output.
It is the rare human who doesn’t wish to change something about his or her brain. In my case, it’s depression, which runs on both sides of my family. I’ve been taking antidepressants for almost twenty years, and they help a lot. But every couple of years the effects wear off, and I have to either up the dose or switch to a different drug—neither process can be repeated indefinitely without the risk of liver or kidney damage. So although my symptoms are under control for now, I worry, depressively, about what will happen when I exhaust the meds. As I was researching this piece, my attention was caught by a number of randomized controlled trials showing a benefit from tDCS for depression. (The data are insufficient to allow definitive conclusions, but larger trials are in progress.) I was almost embarrassed by how excited I felt. What if it was possible to feel less sad—to escape the deterministic cycle of sadness? What if you could do the treatment yourself, at home, without the humiliation and expense of doctors’ visits? I asked Vince Clark whether any private physicians use tDCS outside of a research setting.
New Stuff! Enobio 32: EEG Cap now in 32 channels. Neurosurfer: Combine 2D & 3D (inculding Oculus Rift support) Neurofeedback games. Starstim Home Research Kit: Allows physicians to facilitate telemedicine tDCS sessions. Starstim tCS: Starstim without EEG. NUBE: Cloud data management for your tDCS and EEG studies. (Neuroelectrics has been distributing Starstim devices at the university research level for some years. We should assume they’ve collected a lot of fascinating data.)
Neurosurfer Software in action:
This paper proposes combining tDCS with fNIRS (functional near infrared spectroscopy) for the purpose of monitoring effects of tDCS especially in the context of enhancing cognition, i.e. immediate and direct feedback that tDCS is ‘working’.
Using fNIRS to Monitor the Relationship of Cognitive Workload and Brain Dynamics fNIRS provides an attractive method for continuous monitoring of brain dynamics in both seated or mobile participants. fNIRS is safe, highly portable, user-friendly and relatively inexpensive, with rapid application times and near-zero run-time costs. The most commonly used form of fNIRS uses infrared light, introduced at the scalp, to measure changes in blood oxygenation as oxy-hemoglobin converts to deoxy-hemoglobin during neural activity, i.e., the cerebral hemodynamic response. fNIRS uses specific wavelengths of light to provide measures of cerebral oxygenated and deoxygenated hemoglobin that are correlated with the fMRI BOLD signal. Below we briefly review fNIRS studies of cognitive workload.
Furthermore, from the article, it may be misinterpreted that I starting using tDCS to treat my vision, but this is not true. I have always been interested in self-improvement, and wanted to try new things to become a better person and live my life in the right way. A few months before stumbling upon tDCS, I had started to spend more time in meditation and exercising regularly, as well as taking nutritional supplements and becoming vegetarian. So tDCS seemed like one more thing to try to see if it made a difference for me, and I did not expect that it would affect my vision at all. However, after using it one evening, I noticed that I was able to see better in low light. It was a strange feeling at first, but after trying it for several nights in a row, it was very evident that I could perceive things that I simply couldn’t see before, such as the upper floors of tall buildings, and traffic from more than a few meters away. While my visual acuity remains the same, my contrast perception and ability to notice small objects have noticeably improved.