Anxiety disorder and rTMS effect on left DLPFC in memory retrieval process

Neuroimaging and Transcranial Magnetic Stimulation (TMS) studies showed dorsolateral prefrontal cortex (DLPFC) to be crucial to explain the relationship between anxiety disturbs and the memory performance in case of emotional stimuli processing. The DLPFC is thought to be crucially involved in mechanisms underlying the regulation of emotion, such as inhibition and extinction. Preferred processing of disorder-relevant information and focusing selective attention on it is conceived as an evoking and sustaining factor for anxiety disorders. The ability to suppress this automatic processing is severely impaired in patients with anxiety disorders or high in anxiety trait. The present rTMS study aims to investigate the interaction between memory, emotion and anxiety, focusing on the contribution of rTMS to increase performance in high anxious subjects. Subjects, were divided in two groups depending on their anxiety level (high/low, STAI), were required to perform a double task: an encoding task, where some lists composed by emotional and non-emotional words were presented to the subjects; a retrieval task, where the old stimuli and new stimuli were presented for a recognition performance. A rTMS stimulation was provided during the retrieval phase over the left DLPFC. We found that high trait anxiety subjects revealed a better performance (reduced error rate and RTs) in response to emotional cues when rTMS stimulation was performed on DLPFC. This result suggested that left DLPFC may be specifically involved in the memory retrieval of emotional information and that an increased benefit is obtained for high anxious more than for less anxious subjects.