Targeting the r-dlPFC in Anxiety

The dorsolateral prefrontal cortex (dlPFC) has been previously shown to be implicated in anxiety, cognition, and working memory performance is. Previous work has demonstrated left dlPFC (l-dlPFC) anxiety/task interactions, meaning higher cognitive load and anxiety levels further increase l-dlPFC activation. This suggests the role of the l-dlPFC in anxiety expression. However, individuals with anxiety disorders demonstrate a reduced ability to recruit the right dlPFC (r-dlPFC) during working memory tasks, suggesting aberrant top-down regulation in psychiatric illness.

In this study, we evaluated the role of the r-dlPFC in anxiety, and hypothesized that this area may be involved in top-down anxiety regulation. Given past work demonstrating that the brain state at the time of stimulation influences response to stimulation, we delivered 10 Hz rTMS during a working memory paradigm (Sternberg) known to activate the the target r-dlPFC.  

We targeted the r-dlPFC with TMS using individualized TMS targets from the Sternberg task done during previous fMRI, and utilized electric-field modeling in a protocol we described here to optimize coil position. We found that active rTMS to the

r-dlPFC increased anxiety-potentiated startle, which suggests a link between the r-dlPFC and the physiological expression of anxiety versus top- down anxiety regulation.