Chiara Ferrari

rTMS stimulation on left DLPFC increases the correct recognition of memories for emotional target and distractor words

According to a recent hypothesis, the prefrontal cortex has been proposed as the site of emotional memory integration, because it is sensitive to the recognition of emotional contents. In the present research, we explored the role of the dorsolateral prefrontal cortex (DLPFC) in memory recognition processes for positive versus negative emotional stimuli when old (target) and new (distractor, either semantically related or unrelated to the target) stimuli were presented. The role of the DLPFC was analysed using an rTMS (repeated transcranial magnetic stimulation) paradigm that induced increased cortical activation of the left DLPFC. The subjects were required to perform a task that consisted of two experimental phases (i.e., an encoding and a recognition phase) in which the targets and the distractors were presented and recognition performance was measured. rTMS stimulation was provided over the left DLPFC during the recognition phase. We found that the rTMS stimulation affected the memory recognition of positive emotional material. Moreover, related and unrelated distractors were discarded better when they were positively valenced, and a more significant effect (i.e., increased performance) was produced in response to related distractors. This result suggests that the activation of the left DLPFC favours the memory recognition of positive emotional information, and that such activation is able to induce a more appropriate selective process to distinguish target from distractor stimuli in the presence of more complex processes (related distractors). The valence model of emotional cue processing may explain this increased performance by demonstrating the distinct role of the left hemisphere in the retrieval of positive emotional information.

Emotional memory retrieval. rTMS stimulation on left DLPFC increases the positive memories

A suggestive hypothesis proposed that the lateral prefrontal cortex (LPFC) may be identified as the site of emotion-memory integration, since it was shown to be sensitive to the encoding and retrieval of emotional content. In the present research we explored the role of the dorsolateral prefrontal cortex (DLPFC) in memory retrieval of positive vs. negative emotional stimuli. This effect was analyzed by using an rTMS paradigm that induced a cortical activation of the left DLPFC. Subjects 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; a retrieval phase, where the old stimuli and the new stimuli were presented for a recognition performance. The rTMS stimulation was provided during the retrieval phase over the left DLPFC. We found that the rTMS stimulation over this area affects the memory retrieval of positive emotional material, with higher memory efficiency (reduced RTs). This result suggested that left DLPFC activation promotes the memory retrieval of emotional information. Secondly, the valence model of emotional cue processing may explain decreasing of RTs, by pointing out the distinct role the left hemisphere has in positive emotional cue processing.

rTMS stimulation on left DLPFC affects emotional cue retrieval as a function of anxiety level and gender

Anxiety behaviour showed a consistent attentional bias toward negative and aversive memories, induced by a right dorsolateral prefrontal cortex (DLPFC) hyperactivation. In the present research, we explored the possible effect of rTMS (repeated transcranial magnetic stimulation) on the left DLPFC in memory retrieval of positive versus negative emotional words, to induce a balanced response between the two hemispheres. Moreover, the gender effect in emotional memory processing was verified as a function of the stimulus valence.

Repeated transcranial magnetic stimulation on dorsolateral prefrontal cortex improves performance in emotional memory retrieval as a function of level of anxiety and stimulus valence

Anxiety behavior showed a consistent attentional bias toward negative and aversive memories, induced by a right frontal cortical superiority, based on an unbalance effect between the two hemispheres. The aim of the present study was to explore the role of the left dorsolateral prefrontal cortex (DLPFC) in the memory retrieval process of positive versus negative emotional stimulus, as a function of anxiety level.