Brain stimulation helps socially anxious

Researchers have found that applying a specific pattern of mild electrical stimulation to the brain can help individuals with high social anxiety better control their automatic avoidance behaviors. The findings from this small study of 49 adults were published in The Journal of Neuroscience.

Social anxiety disorder involves an intense fear of social judgment and a strong urge to avoid distressing situations. This avoidance brings temporary relief but ultimately maintains the condition by preventing learning that situations are safe. Standard treatments like exposure therapy require confronting fears, but people with severe social anxiety often struggle to override their automatic urge to flee.

Overcoming this pattern requires emotional action control. This is the brain's ability to suppress automatic reactions and execute a different planned response. Brain regions coordinate this control by communicating through rhythmic electrical impulses, or brainwaves.

The Brain's Control Circuit

When a person needs to override an automatic behavior, an area responsible for cognitive control called the lateral prefrontal cortex must sync its low-frequency rhythms with the high-frequency rhythms of the sensorimotor cortex. The sensorimotor cortex plans and executes physical movements. A team from Radboud University in the Netherlands, led by Sjoerd Meijer and Bob Bramson, tested if artificially enhancing this synchronization could help a clinical population.

They recruited 49 adults screened with the Liebowitz Social Anxiety Scale, focusing on those with scores indicating a high likelihood of daily social anxiety disorder symptoms. Participants performed a task inside an fMRI scanner while holding a joystick and viewing images of faces.

The Experimental Task and Stimulation

In the standard task, participants pulled the joystick toward themselves for happy faces and pushed it away for angry faces. This aligns with natural tendencies to approach positive stimuli and avoid negative ones. In the challenging version, the rules were reversed, forcing participants to override their automatic emotional impulse to pull away from perceived threats.

During the tasks, researchers applied dual-site transcranial alternating current stimulation. This noninvasive technique uses scalp electrodes to deliver weak, oscillating electrical currents designed to mimic and influence the brain's natural rhythms. They tested three conditions.

These conditions alternated in short blocks of about one minute each, with pause periods in between.

Key Findings and Neural Mechanisms

Participants performed better during the in-phase stimulation, making fewer errors on the challenging, reversed-rule task compared to the sham condition. The anti-phase stimulation did not produce statistically significant performance benefits.

The brain imaging data showed the in-phase stimulation strengthened the functional connection between the targeted prefrontal and sensorimotor regions. It also altered activity in the amygdala, a deep brain structure that processes raw emotions like fear and generates automatic defensive reactions.

During in-phase stimulation, the amygdala exerted less influence over the participants' physical joystick movements. The intervention seemed to strengthen the brain's goal-directed pathways, allowing the prefrontal cortex to successfully compete with emotional signals from the amygdala at the level of physical execution.

Behavioral benefits varied. Improvements were largest in individuals whose prefrontal cortex showed the strongest physiological response to the electrical stimulation. Participants with the highest self-reported trait anxiety tended to show the strongest neural responses.

The brain scans revealed a difference in how highly anxious participants process control. Rather than using the frontal pole to integrate emotions and goals, they relied heavily on the dorsolateral prefrontal cortex. This subregion is known for strict rule-based processing, suggesting anxious individuals must rely on rigid rules to bypass their easily overwhelmed emotional centers.

The study relies on fMRI, which tracks blood oxygen levels rather than direct electrical brainwaves. There was high individual variation in how strongly participants' brains reacted to the stimulation. Future research might use individualized computer models to adjust currents based on a person's specific brain structure and investigate if the intervention can produce lasting changes in real-world social settings.