Category Archives: Paper

Modulating and enhancing cognition using brain stimulation: Science and fiction | Roi Cohen Kadosh

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Roi Cohen Kadosh is a leading non-invasive brain stimulation researcher. (Also elsewhere on the blog)

A new line of research opens the possibility of modulating and enhancing human cognition using mild and painless transcranial electrical stimulation (tES), which includes transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS). Such initial findings trigger excitement as well as scepticism. The current review aims to provide a guideline for those who are interested in expanding their research into this field. I will therefore discuss: (1) the principles of tES and its putative mechanisms; (2) its potential to modulate and enhance cognitive abilities; (3) the misconceptions on which scepticism about this method is based; and (4) possible directions for the advancement of this field in which psychologists in general and cognitive psychologists in particular should in my view play a key role. I will conclude that this nascent field, which has been neglected by psychologists, requires their contribution in order to lead to basic and translational advancements on human behaviour.

And another excerpt around the hot topic of ‘transfer’… Basically, that it’s difficult to measure (positive effects of stimulation leading to enhanced intelligence) when we’re not even sure what cognition means.

Transfer effects
Another closely related issue in cognitive enhancement and training is the issue of transfer (Taatgen, 2013). Currently, there is mixed evidence from tES-paired training studies of transfer of tES-training benefits to another task. One of the issues regarding this lack of consistency is the difficulty of selecting appropriate training and transfer tasks, and this in my view is often due to a difficulty in identifying which cognitive functions and brain regions are activated by the specific training material. In other words, the constraint might not be due to the limited potential of tES to induce transfer, but due to suboptimal experimental design. This drawback is not limited to tES, but is a generic problem in the field of rehabilitation and cognitive enhancement (Cohen Kadosh, 2014). Indeed, some studies have shown that tES can even further increase the chance of transfer in paradigms that have struggled to show transfer without stimulation (Cappelletti et al., 2013; Looi, Duta, Huber, Nuerk, & Cohen Kadosh, 2013). Further studies are needed to examine the multifaceted issue of transfer effects, and their possible enhancement using tES. However, in order for such knowledge to progress, a better understanding of the cognitive mechanisms involved is necessary (Taatgen, 2013).

via Taylor & Francis Online :: Modulating and enhancing cognition using brain stimulation: Science and fiction – Journal of Cognitive Psychology – Volume 27, Issue 2.
direct pdf download

How the first brain-altering wearable is being tested | TheDailyDot

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Here we go. The Thync device isn’t tDCS after all.
From the study:

Abstract
We have developed a neuromodulation approach that targets peripheral nerves and utilizes their afferents as signaling conduits to influence brain function. We investigated the effects of this transdermal electrical neurosignaling (TEN) approach on physiological responses to acute stress induction. TEN was targeted to the ophthalmic and maxillary divisions of the right trigeminal nerve and cervical spinal nerve afferents (C2/C3) using high-frequency, pulse-modulated electrical currents. Compared to active sham stimulation, TEN significantly suppressed sympathetic activity in response to acute stress without impeding cognitive performance. This sympatholytic action of TEN was indicated by significant suppression of heart rate variability changes, galvanic skin responses, and salivary α-amylase levels in response to stress. These observations are consistent with the hypothesis that TEN acted partially by modulating activity in the locus coeruleus and subsequent noradrenergic signaling. Dampening sympathetic tone using TEN in such a manner represents a promising approach to managing daily stress and improving brain health.

And as reported by Daily Dot

While I had only 30 minutes of time with Thync, the team told me that it’s been doing in-depth beta testing for a while. Now, Thync is starting to release some of its findings. In a press release this morning, Thync announced a study showing that its device reduces stress without chemicals. Here’s a quick look at how it worked:

In the study, researchers experimentally induced stress in subjects by exposing them to various environmental stimuli causing fear or cognitive pressure. When Thync scientists examined stress biomarkers in the saliva of subjects at different time points throughout the study, they observed something interesting. They found the levels of salivary α-amylase, an enzyme that increases with stress, as well as noradrenergic and sympathetic activity, significantly dropped for the subjects that received electrical neurosignaling compared to the subjects that received the sham.

The results are exactly what Thync has been saying: That it can de-stress us without putting anything into our bodies. It’s an interesting (though admittedly, very academic) look at how Thync works. But the company also helped me understand its testing and offered an anecdotal look at how the device is being used.

via How the first brain-altering wearable is being tested.

Wearable functional Near Infrared Spectroscopy (fNIRS) and tDCS: Expanding Vistas for Neurocognitive Augmentation | Frontiers

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A new generation of functional near infrared spectroscopy (fNIRS) systems is described that are miniaturized, portable, and include wearable sensors. These developments provide an opportunity to couple fNIRS with tDCS, consistent with a neuroergonomics approach for joint neuroimaging and neurostimulation investigations of cognition in complex tasks and in naturalistic conditions. The effects of tDCS on complex task performance and the use of fNIRS for monitoring cognitive workload during task performance are described. Also explained is how fNIRS + tDCS can be used simultaneously for assessing spatial working memory.

via Frontiers | Wearable functional Near Infrared Spectroscopy (fNIRS) and transcranial Direct Current Stimulation (tDCS): Expanding Vistas for Neurocognitive Augmentation | Frontiers in Systems Neuroscience.

Modulating Cognition Using tDCS of the Cerebellum

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There’s a 12 minute video at the original article link below. Including demonstrations of the montage (around 8 minute mark) used in the research.

The procedure demonstrates how performance (accuracy, verbal response latency and variability) could be selectively improved after cathodal stimulation, but only during tasks that the participants rated as difficult, and not easy. Performance was unchanged by anodal or sham stimulation. These findings demonstrate a role for the cerebellum in cognition, whereby activity in the left prefrontal cortex is likely dis-inhibited by cathodal tDCS over the right cerebellar cortex. Transcranial brain stimulation is growing in popularity in various labs and clinics. However, the after-effects of tDCS are inconsistent between individuals and not always polarity-specific, and may even be task- or load-specific, all of which requires further study. Future efforts might also be guided towards neuro-enhancement in cerebellar patients presenting with cognitive impairment once a better understanding of brain stimulation mechanisms has emerged.

via Modulating Cognition Using Transcranial Direct Current … | Protocol.

How the brain ignores distractions | News from Brown

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As our awareness of brainwave activity mapped to behavior evolves, we’re sure to see the development of tACS for treatment and enhancement. I am betting that Neurolectrics, with their lab-level NIB/EEG device, Starstim, have been collecting valuable data in this area.

Jones and Kerr are now working with Dr. Ben Greenberg, professor of psychiatry and human behavior, to test whether they can use noninvasive, transcranial alternating current electrical stimulation (tACS) to take advantage of this process. They will test whether they can use the technology to manipulate alpha and beta waves between parts of the brain such as the somatosensory cortex and the rIFC to suppress attention to, or even the detection of, pain.

In a similar vein, research results show that mindfulness meditation, also possibly via the mechanism of throttling attention via control of alpha rhythms, can help people ignore depressive thoughts. Jones and Kerr are also interested to study whether explicit manipulation of alpha and beta waves between a different part of the cortex and the rIFC could provide much the same relief.

The Brown Institute for Brain Science recently outfitted a new lab on campus with the needed hardware for tACS and other brain stimulation research. BIBS and the Norman Prince Neurosciences Institute are funding the collaboration with Greenberg.

via How the brain ignores distractions | News from Brown.

The effects of theta transcranial alternating current stimulation – PubMed

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Especially in light of the recent Aldis Sipolins study which found no transfer (improvement to fluid intelligence) with his tDCS/exercise protocol, I think it’s smart to keep our eye on tACS. Although far less researched, I’ve noticed consistent reports of positive effects. Google the article title and you can find a few links to full pdfs.

The results showed that active theta tACS affected spectral power in theta and alpha frequency bands. In addition, active theta tACS improved performance on tests of fluid intelligence. This influence was more pronounced in the group of participants that received stimulation to the left parietal area than in the group of participants that received stimulation to the left frontal area. Left parietal tACS increased performance on the difficult test items of both tests (RAPM and PF&C) whereas left frontal tACS increased performance only on the easy test items of one test (RAPM). The observed behavioral tACS influences were also accompanied by changes in neuroelectric activity. The behavioral and neuroelectric data tentatively support the P-FIT neurobiological model of intelligence.

via The effects of theta transcranial alternating current stimulation (… – PubMed – NCBI.

Brain Hackers Beware: Scientist Says tDCS Has No Effect – IEEE Spectrum

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Jared Horvath, a neuroscientist at the University of Melbourne, in Australia, looked at every study of transcranial direct current stimulation (tDCS) that reported an impact on cognitive and behavioral activities such as problem solving, learning, mental arithmetic, vision tasks, and memory games. He then excluded results that had not been replicated by other researchers, as well as any experiments lacking a “sham condition” control group—where participants were connected to the device but didn’t receive current. While many of the more than 200 individual studies that remained claimed to have found significant effects, those effects disappeared after Horvath’s number crunching. “When I pulled out the 20 studies looking at tDCS and working memory, for example, they all found something, but they all found something different,” says Horvath.

One study may have found an effect on accuracy, another on reaction time, and a third on response confidence. “But when I brought them together, they just canceled each other out, and I was left with nothing,” he says. It was a similar story for more than 100 other cognitive and behavioral outcomes. “It looks like the evidence says tDCS is not doing anything.”

via Brain Hackers Beware: Scientist Says tDCS Has No Effect – IEEE Spectrum.

Tdcs Journal Entry 1 | Steve Hockenyos

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tdcsPlacementsImproveInsightbrian
Steve Hockenyos is demonstrating a montage he got from tDCSplacements.com which purports to Improve Insightfulness (Cathode T3, Anode T4). The ‘BraiNet Placement Cap’ Steve is using can be found at bio-medical.com. (For comparison, have a look at Soterix’s, ‘Easy Strap‘.) Hoping Steve continues this video tDCS journal! [Update: 1/11/15 Steve seems to be doing this daily. He’s not said yet whether his experiment is producing results.]

The anodal tDCS over the left posterior parietal cortex enhances attention toward a focus word in a sentence | Frontiers in Human Neuroscience

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In order to activate the left PPC (atDCS), the anodal electrode was placed over P3 in accordance with the 10–20 international system. The cathodal electrode was attached to the contralateral supraorbital area.

Fig2a

Head locations for the electrodes. The target region was the left posterior parietal cortex where the center of the electrodes was located at P3 in the 10–20 international measurement. The reference patch was located just above the eyebrow.

 

via Frontiers | The anodal tDCS over the left posterior parietal cortex enhances attention toward a focus word in a sentence | Frontiers in Human Neuroscience.

Has the brain-zap backlash begun? | New Scientist

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I think of Vincent Walsh as the most skeptical of the tDCS researchers. You can get a clear understanding of his doubts and concerns in this video from the Davis Summit on tDCS from 2013. https://www.youtube.com/watch?v=9fz7r8VDV4o

However, Vincent Walsh, a cognitive neuroscientist at University College London, is less convinced. “This is an important paper,” he says, especially because it casts doubt on the aspect of this research that until now had been assumed to be the most robust – the physiology.
“In terms of cognition, which is the other aspect that people make claims about, tDCS is massively hyped. The danger is that people have been promised better memories, better reading, better maths, increased intelligence… you name it. The effects are small, short lasting, and no substantial claims have been replicated across laboratories. This paper is hopefully the beginning of a counterweight to all the bullshit.”

via Has the brain-zap backlash begun? – health – 28 November 2014 – New Scientist.

Forget Coffee, Techies Giving Brain An Electric Jolt To Stay More Focused | CBS San Francisco

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“Especially in the San Francisco Bay Area, where everyone is a hacker of some type or the other…you’ve got a lot of people who don’t have any qualms about hooking some electrical thing to their head where they may not know how it works,” said Jared Seehafer.
But before you scrounge around for parts…
“I sure wouldn’t put anything I made for $25 on my head and turn on the switch,” says Stanford Law & Bio-sciences Director Hank Greely, who specializes in the ethical, legal and social implications of these new technologies. “Before you run volts through your brain, um, I think it’s really important to try to make sure that it’s safe and it’s effective.”

via Forget Coffee, Techies Giving Brain An Electric Jolt To Stay More Focused « CBS San Francisco.

Signal to Noise — BrainKit:A Combination Brain Mapping and…

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You’re more likely to know Nathan Whitmore as /u/ohsnapitsnathan, one of the moderators at the tDCS subReddit. Around making plans to attend NYC Neuromodulation Conference 2015, he’s started a GoFundMe campaign and announced an early Beta of his tDCS device, BrainKit. It’s a very ambitious project! He plans to include sensors that would  monitor brain activity using capacitance (Electrical Capacitance Volume Tomography)! The BrainKit would then generate optimal montages for specific desired effects! It’s Arduino based, and Nathan intends for it to be Open Source. It’s very early in the BrainKit’s development, but it appears to me that all the pieces are in place.

A feature new to BrainKit is the ability to act on this information by designing a montage. BrainKit’s montage designing algorithm is actually quite simple, and based on the principles that:
1. If increased performance on a psychometric measure is associated with higher excitability in a cortical area, BrainKit will deliver anodal stimulation to that area, if decreased excitability is associated with increased performance then BrainKit will use cathodal stimulation.
2. If functional connectivity between two electrodes is positively associated with good performance, anodal stimulation is delivered to both electrodes, if it is negatively associated with good performance then cathodal stimulation is applied to both electrodes.
3. If any electrode conflicts exist the previous two rules cause one electrodes to be marked for both anodal and cathodal stimulation, that electrode is excluded from the montage.

via: http://quicktotheratcave.tumblr.com/post/97705478253/brainkit-a-combination-brain-mapping-and

Help me go to NYC Neuromodulation by Nathan Whitmore – GoFundMe

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Hi! I’m Nathan Whitmore, AKA /u/ohsnapitsnathan . I design open-source, DIY brain stimulators OpenStim and BrainKit and I moderate Reddit’s brain stimulator forum. I’m raising money to go to the New York Neuromodulation conference this January and talk about open-source brain stimulators and the DIY community!
WHY: While I currently work in a research lab studying how the brain controls attention, I’m really a tDCS DIYer at heart—I built my first tDCS unit two years ago, when I was in college, and started working on OpenStim a few months later. What these experiences made me aware of is that there’s a large and growing communication gap between people who research tDCS, and the vast majority of those who actually use it. That’s bad for everyone, because it means that what we research and what we actually care about start to diverge.

via Help me go to NYC Neuromodulation by Nathan Whitmore – GoFundMe.

Transcranial stimulation of the developing brain: a plea for extreme caution | Frontiers in Human Neuroscience

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I will focus on the key unknowns in brain stimulation research:
1. The unknown effects of stimulation;
2. The unknown side-effects of stimulation;
3. The lack of clear dosing guidelines;
4. The lack of translational studies from adults to children.
I will set out these “known unknowns” in translating our knowledge about TMS and tDCS effects to clinical pediatric applications, and touch on the practical and ethical barriers to their widespread usage.

via Frontiers | Transcranial stimulation of the developing brain: a plea for extreme caution | Frontiers in Human Neuroscience.