Running an electric current through the brains of patients brings back bad memories of electroshock therapy from the 1950’s. Nurse Ratched perhaps was most responsible for an instinctual rejection of electroshock therapy, and has done quite a bit to halt much of the related research.
Researchers at Vanderbilt University have known that within the medial-frontal cortex exists a component of the brain that creates an electric signal whenever the owner of the brain realizes that he or she made a mistake. The researchers hypothesized that this signal may be related to the way we learn from our mistakes, triggering the brain’s corrective functions that help to prevent a similar decision. To test if it’s true, and if the process can be regulated externally, the researchers used transcranial direct current stimulation (tDCS) to stimulate the medial-frontal cortex in a variety of ways. They discovered that the current either amplifies or retards the mistake realization signal, depending on its direction, and that the technology can be applied to either help improve learning or show the smart ones what it’s like to be a know nothing.
We hope this technology finds use in helping overcome ADHD and other learning disorders, and perhaps can lead to new therapy options for other psychiatric conditions.
When anodal current was applied, the spike was almost twice as large on average and was significantly higher in a majority of the individuals tested (about 75 percent of all subjects across four experiments). This was reflected in their behavior; they made fewer errors and learned from their mistakes more quickly than they did after the sham stimulus. When cathodal current was applied, the researchers observed the opposite result: The spike was significantly smaller, and the subjects made more errors and took longer to learn the task.
The effect was not noticeable to the subjects—their error rates only varied about 4 percent either way, and the behavioral adjustments adjusted by a matter of only 20 milliseconds—but they were plain to see on the EEG. “This success rate is far better than that observed in studies of pharmaceuticals or other types of psychological therapy,” said Woodman.
The researchers found that the effects of a 20-minute stimulation did transfer to other tasks and lasted about five hours.
Study in The Journal of Neuroscience: Causal Control of Medial–Frontal Cortex Governs Electrophysiological and Behavioral Indices of Performance Monitoring and Learning…