When a certain type of brain stimulation, known as transcranial direct current stimulation (tDCS), targets the brain’s dorsolateral prefrontal cortex (involved in the control of attention), it allows a person to more easily adjust his attention to threat, according to a new study. The findings are published in the journal Biological Psychiatry.
People who suffer from anxiety tend to pay greater attention to threatening stimuli in their environment. Instead of thinking of pleasant thoughts, they have a bias towards threatening information, further contributing to their higher levels of anxiety.
The painless brain procedure uses weak electrical currents to deliver targeted stimulation to the brain via electrodes on the scalp. It has already shown promise in treating mood, anxiety, cognition, and certain symptoms of Parkinson’s disease.
Neurostimulation was found to be especially effective when combined with a cognitive training technique, called attention bias modification (ABM). This cognitive treatment also targets the pattern of thinking that is biased toward threats.
Therefore, it seemed reasonable to the researchers that neurostimulation targeted at an attention-controlling region of the brain would increase the effectiveness of ABM.
For the study, a total of 77 healthy volunteers received either active tDCS or sham stimulation while completing an ABM task in which they were specifically instructed to either pay attention to or avoid a threat.
The participants who received active stimulation showed greater control over their attention in the direction encouraged by the training, compared with those who received sham stimulation.
This study provides evidence that ABM interventions can be enhanced with targeted neurostimulation.
“Specifically, it shows how neuroimaging findings can identify appropriate targets for the therapeutic application of neurostimulation, which serves to increase the efficacy of clinical interventions in ways likely to improve patient treatment,” said lead author Dr. Patrick Clarke from the University of Western Australia.
“The results of this study hold direct implications for improving the clinical outcomes delivered by ABM interventions, for individuals with emotional pathology and for those suffering from other conditions that reflect maladaptive patterns of selective attention,” he added.
Future research is necessary before clinical application, but the results are encouraging. The next steps are to test the combined effectiveness of tDCS and ABM on symptoms of clinically anxious people.
“The neurobiology underlying tDCS is still being worked out, but this study suggests that one way it may advance treatment is to increase neuroplasticity and promote the efficacy of cognitive training,” said Dr. John Krystal, editor of Biological Psychiatry.