If asked, most people can easily recall a time when their brain was stimulated by something: a fascinating film, an engaging concert, an intense video game, a new friend. Most people probably can’t think of a time when their brain was literally stimulated, however. In fact, for most people, the idea of literal brain stimulation is probably pretty scary, and evokes terrifying terminology like shock therapy.
The popular portrayal of brain stimulation paints the patient, who is often trapped in a straightjacket and receiving the “treatment” against their will, as a zombified husk of their former self, incapable of coherent speech and housed in an asylum (Jack Nicholson’s character in the classic film One Flew Over the Cuckoo’s Nest is probably the best example). Following that narrative, nobody in their right mind would willingly undergo such a barbaric form of therapy, no matter how seriously they were suffering.
In reality, the portrayals of brain stimulation in television and movies only tell part of the story. Modern forms of brain stimulation are safer and more effective than ever, and can provide valuable treatment options for patients with no other place to turn.
The earliest known applications of brain stimulation date back nearly 2000 years, when Ancient Roman doctors treated headaches by placing electric fish on their patients’ heads. The Romans were using a weak form of transcranial direct current stimulation (tDCS), which is still used today for treating depression and other mood disorders, though modern physicians have traded out the fish for sophisticated batteries and electrodes.
The most well-known form of brain stimulation is electroconvulsive therapy (ECT), which was originally developed in the 1930’s as a cure for schizophrenia. ECT is like tDCS on steroids: the goal of ECT is to deliver enough electricity to the patient’s brain to cause a seizure, which can actually be beneficial in some cases, but can also lead to some scary side effects (broken bones, personality changes, and permanent memory loss).
One of the newest tools for stimulating the brain is called transcranial magnetic stimulation (TMS), and as the name implies, it uses a powerful magnet to cause changes in the brain. Compared to tDCS and ECT, TMS is significantly more precise – it can affect an area of the brain as small as a square centimeter – and its effects can be quite clear. Stimulating the part of the brain that controls the thumb causes people’s thumbs to twitch, and stimulating the part of the brain that controls vision can make people see spots!
Why are there so many ways to stimulate the brain today? Different tools are better suited for different situations. tDCS is mild and painless, and so it is better for children and frail adults than ECT or TMS; ECT can lead to dramatic changes in mood more quickly than the other techniques; and TMS has the best precision of the lot.
In terms of treatment applications, though, many ailments respond to all three flavors of stimulation. The most common example of this is severe depression. If a person suffers from depression, generally their doctors will prescribe medication and cognitive-behavioral therapy as a first step. If the medicine and therapy doesn’t work, though, they may be prescribed brain stimulation treatment, and all three tools have been shown to improve symptoms of depression in a lot of patients.
However, there are other times when one tool is significantly better than the rest. For example, some people have language or movement disorders (like weakness or paralysis) after surviving a stroke. There would be no reason to prescribe ECT for these people: they have already suffered significant brain trauma as is, and seizures would only make things worse. tDCS doesn’t cause any additional damage, but the improvements are generally small and take time to develop. TMS, though, is powerful enough to cause significant improvements in a short amount of time, and precise enough to only target the specific parts of the brain that may influence recovery.
Similarly, in kids with reading disorders, ECT and TMS are too powerful and noxious to be realistic treatment options, but tDCS could certainly be employed to give the children’s brains a boost, and could even be applied at the same time as a remedial reading therapy for an even bigger potential improvement. This technique has already been validated in adults with reading difficulties.
So in the end, there are plenty of ways to stimulate the brain safely and effectively, and plenty of reasons to do it. Of course, no treatment is ever going to be perfect: tDCS can’t target very specific parts of the brain; ECT has some dramatic side effects; and TMS can be uncomfortable bordering on painful. We still don’t even know why stimulation treatments are effective for some people but not for others. But brain stimulation treatments have come a long way since the first Roman used a fish to treat a headache. Given the recent push toward funding more research on the brain, brain stimulation techniques could improve more over the next two decades than they did in the last two millennia.
Changing the public perception of brain stimulation may be an even bigger challenge, however. Still, it isn’t unreasonable to hope that sometime in the near future, people don’t immediately cringe when they’re confronted with brain stimulation treatments, but rather think of someone they know who actually benefitted from the treatment, and can walk or talk again, or wake up without feeling depressed. Our brains are the most important assets we have, and the more we learn about how to fix them when they malfunction, the better our lives will be.