Right now, billions of neurons in your brain are working hard as you read this. They’re creating a brain wave doctors can actually see on an electroencephalogram, or EEG, as a line rising and falling, rising and falling. Sometimes, when our brains are impaired by things like mental illness or chronic pain, researchers can see the effects on an EEG.
What if doctors could repair that brain wave? Would that help improve brain-related conditions such as depression and schizophrenia, or even chronic pain? UNC School of Medicine researchers think so and are busy figuring out how it works. They don’t want to prescribe drugs; they want to prescribe electricity, in the form of electrical brain stimulation.
The Electrical Brain
There are several kinds of brain waves, depending on our state of consciousness. Each kind of wave involves a different amount of electricity. For instance, beta waves occur at 12 to 30 hertz of electricity. They dominate the brain when our neurons are really working hard—when we’re alert, focused and doing the basic brain computations we do throughout most of the day.
Alpha waves—8 to 12 hertz—occur when we’re sleeping, daydreaming, meditating or even “in the zone” of athletic activity. In the past, scientists thought alpha waves were showing the brain was idle, like a car just keeping warm, but there appears to be more to it.
“Now we think alpha oscillations are actually quite important to how the brain functions,” says Flavio Frohlich, PhD, a neuroscientist in the Department of Psychiatry at the medical school. “We think they’re so important that enhancing them might actually benefit individuals who suffer from depression and other conditions, such as schizophrenia and chronic pain.”
For instance, research suggests that people with depression have weak alpha oscillations and that boosting them could help. Brain stimulation, which involves running a weak electrical current through electrodes attached to the scalp, is one way to do that.
If you’re thinking “electroshock” therapy, think again. Electroconvulsive therapy uses 180 to 460 volts of electricity, lasts one to six seconds, and is done under general anesthesia. While it has a place in medical care, it’s only for severe, treatment-resistant mental disorders.
The brain stimulation investigated by Dr. Frohlich and his team, on the other hand, uses much less electricity. The patient is awake and maybe feels a bit of tingling on the scalp. Some people feel nothing.
Researchers apply a constant stream of electricity at a low rate across or in specific parts of the scalp. Then they test to see if that stimulation affected the part of the brain they’re trying to study. This is called transcranial direct current stimulation, or tDCS, and it’s commonly used in neuroscience research to study all kinds of things, such as boosting IQ and creativity and helping people with psychiatric conditions.
Dr. Frohlich takes a unique approach. His lab uses electrical brain stimulation to home in on a particular wave pattern, usually the alpha oscillations. This more precise, individualized method is called transcranial alternating current stimulation, or tACS.
“The idea is if we can lock in on that wave pattern, then we might be able to enhance it,” Dr. Frohlich says. “And if that’s possible, then we might be able to help people with impaired alpha oscillations. There are people that are cognitively impaired and need help, and sometimes there are no medications that help or the drugs have serious side effects.”
In one study, Dr. Frohlich’s lab used tACS to substantially boost creativity in healthy volunteers. It was an important study that showed the first evidence that enhancing alpha oscillations could trigger a specific, complex behavior (in this case, creativity).
“Think of it like this,” Dr. Frohlich says. “People with depression are stuck in a thought pattern. They can struggle to fully engage with reality. We know that some of them, at least, have impaired alpha oscillations. We think it’s very possible to restore those alpha waves in a meaningful and noninvasive way.”
Other research suggests that people with chronic pain experience a kind of “neural rut” that’s tough to escape. Their brains get used to the body being in pain. Dr. Frohlich wants to know if tACS can help them, too.
Word of Caution, World of Hope
Dr. Frohlich says more studies are needed, and he cautioned against using electrical brain stimulation to boost creativity or brain functioning in healthy brains.
“We don’t know if there are long-term safety concerns,” he says. “We did a well-controlled, one-time study and found an acute effect. Also, I have strong ethical concerns about cognitive enhancement for healthy adults, just as sports fans might have concerns about athletic enhancement through the use of performance-enhancing drugs.”
Instead, Dr. Frohlich is focused on treating people with mental and neurological conditions, such as depression, schizophrenia and even Alzheimer’s disease, for which cognitive deficits during everyday life are a major problem. Dr. Frohlich thinks tACS has the potential to help millions of people with mental or neurological illness navigate life.
For example, people with schizophrenia or major depressive disorder may have periods of severe symptoms or “breakdowns” separated by periods of relative calm. During these times, their brains are still impaired by illness. Electrical brain stimulation might provide additional relief in these periods.
Dr. Frohlich and his colleagues have also showed that tACS restores alpha waves and potentially reduces auditory hallucinations in patients with schizophrenia.
“We think it’s possible to offer brain stimulation as a way to help these people during their everyday lives, and that’s what we’re working on,” Dr. Frohlich says. “Helping these populations of people is why we do this kind of research.”
Dr. Frohlich and his colleagues are recruiting participants for a study on brain stimulation for chronic lower back pain, and for a follow-up study on brain stimulation for patients with auditory hallucinations in schizophrenia.
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