Left DLPFC rTMS stimulation reduced the anxiety bias effect or how to restore the positive memory processing in...

In the present research we explored the role of the dorsolateral prefrontal cortex (DLPFC) in memory retrieval process of positive vs. negative emotional stimulus, as a function of the anxiety levels. Anxiety behavior showed a consistent attentional bias toward negative and aversive memories, induced by a right frontal cortical superiority. This effect was analyzed by using a rTMS paradigm that induced a cortical activation of the left DLPFC. Subjects, who were divided in two different groups depending on their anxiety level (high/low-anxiety, State-Trait-Anxiety-Inventory, STAI), were required to perform a task consisting of two experimental phases: an encoding-phase, where some lists composed by positive and negative emotional words were presented to the subjects; and a retrieval-phase, where the old stimuli and new stimuli were presented for a recognition performance. We found that the rTMS stimulation affects the memory retrieval of emotional material. High-anxiety subjects benefit in greater measure from the left DLPFC stimulation with a reduced negative bias. This result suggested that left DLPFC activation favors the memory retrieval of positive emotional information and might limit the "unbalance effect" induced by a right hemispheric superiority at a high level of anxiety. The potentiality of TMS for anxiety behavior modulation was also discussed.