Anxiety Patients Rely On Bilateral DLPFC Activation During Verbal Working Memory

One of the hallmarks of anxiety disorders is impaired cognitive control, affecting working memory (WM). The dorsolateral prefrontal cortex (dlPFC) is critical for WM, however it is still unclear how dlPFC activity relates to WM impairments in patients. Forty-one healthy volunteers and 32 anxiety (general and/or social anxiety disorder) patients completed the Sternberg WM paradigm during safety and unpredictable shock threat. On each trial a series of letters was presented, followed by brief retention and response intervals. On low and high load trials, subjects retained the series (5 and 8 letters, respectively) in the original order, while on sort trials subjects rearranged the series (5 letters) in alphabetical order. We sampled BOLD activity during retention using a bilateral anatomical dlPFC mask. Compared to controls, patients showed increased reaction time during high load, greater right dlPFC activity, and reduced dlPFC activity during threat. These results suggest that WM performance for patients and controls may rely on distinct patterns of dlPFC activity with patients requiring bilateral dlPFC activity. These results are consistent with reduced efficiency of WM in anxiety patients. This reduced efficiency may be due to an inefficient allocation of dlPFC resources across hemispheres or a decreased overall dlPFC capacity.