Non-Invasive Brain Stimulation for Athletes?

Will athletes in the future begin to use non-invasive brain stimulation to get an edge over the competition? Already researchers have used transcranial direct current stimulation tDCS (a non-invasive way to electrically stimulate the brain) to reduce exercise dependent fatigue.

Neuromuscular fatigue is the exercise-dependent decrease in the ability of muscle fibres to generate force. To investigate whether manipulation of brain excitability by transcranial direct current stimulation (tDCS; 1.5 mA, 10 min, 0.026 C/cm(2)) modulates neuromuscular fatigue, we evaluated the effect of brain polarization over the right motor areas of the cerebral cortex of healthy subjects on the endurance time for a submaximal isometric contraction of left elbow flexors.

The researchers found that anodal tDCS (which activates brain areas) was able to decrease fatigue related muscle pain.

Anodal tDCS could improve endurance time by directly modulating motor cortical excitability, modulating premotor areas, decreasing fatigue-related muscle pain, increasing motivation and improving synergist muscle coupling.

I mentioned in the past about using transcranial magnetic stimulation to improve the working memory deficits associated with sleep deprivation. So this technology might be able to improve an athletes concentration from too much fatigue. It may also be able to enhance regular concentration as well. I also discussed about using deep transcranial magnetic stimulation to target the reward areas of the brain with electromagnetism. Doing this may allow researchers to artificially induce a euphoric or stimulant like effect in the subject by selectively stimulating or inhibiting specific brain regions. This would be beneficial for long term endurance where a large boost in mood is necessary for optimal performance. Deep TMS may be able to target several different regions of the brain to improve performance in a variety of tasks.

The banned substance list (pdf) of the recent olympic games does not mention using non-invasive brain stimulation, however both transcranial magnetic stimulation or transcranial direct current stimulation could potentially find increasing use by athletes in the future. It may still be a little early to know how useful these types of technologies would be for athletes. As for cheating, it would be nearly impossible to detect if someone had undergone non-invasive brain stimulation. They wouldn't be able to have any drug tests that could detect this type of treatment. The only plausible method of detection might be a brain scan. So this could be an effective way of brain doping while sidestepping any negative penalties. This is all speculative of course, and it is unclear if these types of brain stimulation would enough of an effect on an athletes performance to be worthwhile.

Electric Brain Stimulation to Help Bad Drivers

Can brain stimulation make you a better driver? In the past I've mentioned transcranial direct current stimulation (tDCS) as a method to non-invasively stimulate areas on the brain's outer layer (the neocortex) selectively with a small amount of electricity. With this technology, you basically place two sponge electrodes on your head that are connected to a 9 volt battery. The sponge electrode attached to the anode (+) excites brain activity beneath it, while the sponge electrode connected to the cathode (-) decreases brain activity underneath it. This technology can be performed on a person while they are fully awake and it has few side effects aside from a slight tingling sensation. Researchers have been using this technology for some interesting experiments. In a recent one, they targeted an area of the brain called the dorsolateral prefrontal cortex (DLPFC) for excitation to see its influence on driving activity. This area of the brain is involved with executive functioning and low activity here is associated with risk taking activity.

At a neural level, risk-taking behavior, decision-making and impulsiveness share similar neural networks in the dorsolateral prefrontal cortex (DLPFC). Patients with lesions in the DLPFC (especially in the right hemisphere) show riskier behavior than a healthy control group.

They applied tDCS to both the left and right DLPFC for 15 minutes to upregulate activity.

In this study, driving performance of twenty-four male participants was tested in a high-end driving simulator before and after the application of transcranial direct current stimulation (tDCS) for 15 minutes over the left or right DLPFC.

They found that doing this actually alters driving behavior and makes people more cautious.

We show that external modulation of both, the left and the right, DLPFC directly influences driving behavior. Excitation of the DLPFC (by applying anodal tDCS) leads to a more careful driving style in virtual scenarios without the participants noticing changes in their behavior.

Are these results surprising? Not really. tDCS has already been used numerous times to reduce risky behavior when people are performing other activities. Do these researchers have too much time on their hands? Maybe. I can imagine in the future instead of getting a fine for going through a red traffic light, you might get a citation requiring you to undergo a round of non-invasive brain stimulation to keep your risk taking behavior in check. Decreasing risky behavior might be beneficial for all sorts of population groups, like those who are addicted to drugs or criminals. Whether this technology will ever actually be used on those populations is another question entirely. There's nothing theoretically stopping a person from performing stimulation on themselves if they so desire. You can read the whole study here "Brain stimulation modulates driving behavior".

TMS and Migraines

A portable transcranial magnetic stimulation (tms) device has been successfully used to reduce migraine headaches. Migraine headaches are usually pulsating and localized to one side of the brain. They typically can last from 4 to 72 hours. Migraine headaches are often accompanied by nausea, vomiting and sensivity to sight/hearing. Researchers performed a multi-center clinical trial of 164 patients. They found that 39 percent of patients were migraine free two hours after TMS treatment compared to only 22 percent recieving sham/placebo TMS. The adverse reactions from this device were also minimal and similar to the sham/placebo.

The cause of migraines is currently unknown. Migraines have been associated with altered cortical brain excitability. Migraines and epilepsy have been linked to one another, suggesting a common brain disturbance.

"The comorbidity between epilepsy and migraine has been well known for a century, yet it is still not fully understood; the two disorders also share some risk factors, symptoms, and preventive drug therapy. A series of clinical observations and scientific data support the hypothesis of alteration of cortical excitability as a possible mechanism underlying their pathology, with both disorders characterized by transient paroxysmal neurological disturbance. So far, the numerous pathophysiological mechanisms responsible for neuronal hyperexcitability have only been studied in familial hemiplegic migraine (FHM), but they do suggest a link between migraine and epilepsy."

Researchers have used low frequency TMS stimulation to reduce hyperexcitability of the occipital cortex. Low frequency stimulation reduces activity in that specific area of the brain and this resolves migraine symptoms.

"Recent studies showed hyperexcitability of the occipital cortex in subjects affected by migraine with aura. It has been shown that 1 Hz repetitive transcranial magnetic stimulation (rTMS) reduces excitability of visual cortex in normal subjects. The aim of the study was to investigate the effects of low frequency (1 Hz) rTMS on visual cortical excitability by measuring changes in phosphene threshold (PT) in subjects with migraine with aura."

Transcranial direct current stimulation has also been used for migraines and may be a cheaper alternative to TMS.

"If the tDCS treatment makes it through clinical trials, migraine sufferers may end up with a treatment safe enough to use without a physician present and whose only side effect would be a slight tingling sensation. Adding to the good news: “I can’t see it costing more than $10,” Zaghi says."

Currently neither TMS nor tDCS is approved by the FDA for the treatment of migraines. However you may be able to get treatment off label at certain brain stimulation centers around the US.

You can watch a CBS news video about this new technology below.

tDCS

Technology review has an interesting article about transcranial direct current stimulation (tDCS)

"The device is simple: a nine-volt battery that's been approved by the Food and Drug Administration for delivering (electricity) across the skin is connected to large flat sponges that are moistened and then applied to the head."

It also mentions about being able to create a device yourself with parts from radioshack.

"Half the people in this room could build this type of device with parts from RadioShack," Wassermann told a crowd at a neurotechnology conference in Cleveland last week.

Transcranial direct current stimulation (tDCS) has several benefits that may make this a fairly useful treatment in the near future. For one thing, it doesn't appear to have the risk of causing a seizure that is associated with transcranial magnetic stimulation (TMS). tDCS can also simultaneously upregulate activity in one area of the brain while decreasing activity in another. The electrode attached to the anode increases brain activity while the electrode attached to the cathode decreases brain activity. For many brain disorders it is common to have certain areas that are overactive or under active compared to a normal brain. So being able to selectively activate or deactivate cortical brain areas at the same time may be beneficial for mental illness.

Scientists are testing tDCS for schizophrenia and depression. Schizophrenics often have what are called negative symptoms. Negative symptoms include apathy, poor attention, poor grooming habits and poor motivation. These symptoms have been associated with under activity of the frontal lobes, particularly a brain area called the left dorsolateral prefrontal cortex. Positive schizophrenic symptoms such as hallucinations may be associated with over activity in different brain areas, like the temporal cortex. So tDCS may be able to up regulate activity in the left dorsolateral prefrontal cortex while simultaneously decreasing activity in the temporal cortex. This could have a substantial impact on a range of schizophrenic symptoms. For depression, tDCS may be able to up regulate activity in the left dorsolateral prefrontal cortex while simultaneously decreasing activity in the right dorsolateral prefrontal cortex. This will likely have a more robust antidepressant effect. TMS can also both increase and decrease activity in brain regions, however it cannot do it simultaneously like tDCS can.

Another benefit to tDCS is that the device is highly portable. This means that scientists can perform brain stimulation on patients while they are on the go, or when they are performing certain tasks. With TMS, it is much harder to do this since TMS is a fairly bulky device and you have to be lying down to get brain stimulation. With tDCS, a much wider variety of experiments become available. For instance recently scientists have used tDCS to reduce subjects propensity to punish unfair behavior in a game.

"Studying social behavior often requires the simultaneous interaction of many subjects. As yet, however, no painless, noninvasive brain stimulation tool existed that allowed the simultaneous affection of brain processes in many interacting subjects. Here we show that transcranial direct current stimulation (tDCS) can overcome these limits. We apply right prefrontal cathodal tDCS and show that subjects' propensity to punish unfair behavior is reduced significantly."

Experiments like this would not be possible with TMS due to the non-portability of the TMS device. So overall, tDCS has many potential uses as a fairly cheap and effective way to alter an individuals brain functioning.

Transcranial Direct Current Stimulation (tDCS)

Can you really affect the way your brain works by using a 9 volt battery? Apparently so with something that has been garnering attention recently called transcranial direct curent stimulation (tDCS). The basic idea is to attach electrodes to your head and allow a small, controlled 1 to 2 millamp current to pass through using a device powered by a battery. This sounds similar to Electroshock (ECT) but it is actually quite a bit different than that. ECT requires anaesthesia and gives the brain a 1 Amp (1000 millamps) jolt that causes a seizure. ECT drastically affects the functioning of the entire brain. tDCS, on the other hand, is much more selective. It only influences the area of the brain directly underneath the electrode that is close to your skull. Anodal stimulation has the ability to excite neuron firing while the cathode does the opposite. So specific brain areas can either be activated or deactivated in response to the current.

Researchers have shown that in healthy volunteers placing the anode over an area of the brain called the left dorsolateral prefrontal cortex (LDPFC) can improve a subjects ability to generate a list of words. tDCS also has the ability to improve working memory and can treat the symptoms of depression when applied over that very same area of the brain. The study done on depressed patients is only a preliminary one and there are still more questions to be answered. Now, though, the New York State Psychiatric Institute is running a new trial to see if they can get the same results. tDCS has also been used to modify pain perception, so this may become a useful treatment for those who have unmanageable pain. tDCS has numerous other uses as well. When applied over the DLPFC, it can modulate the desire for specific foods. It can also diminish risk taking behavior, improve naming in aphasia, improve spatial tactile acuity and enhance language performance when targeted at specific areas of the brain.

There are both positives and negatives to using this type of device. One positive thing about this technology is that it is much cheaper to use than transcranial magnetic therapy. It also doesn't require a person to undergo anaesthesia, so you can basically use the technology on yourself (assuming you know what you are doing). The disadvantages are that it can only target brain areas that are near year skull, it can't touch deeper brain structures. It is also less selective in its targeting ability when compared to transcranial magnetic therapy. You can buy a specialized device to control and deliver the current. I don't recommend doing it quite yet. It may be a few more years before scientists can say for sure whether this technology is worthwhile or not. However it definitely holds a lot of promise.