Hearing fearful prosody impairs visual working memory maintenance.

Interference by distractors has been associated multiple times with diminished visual and auditory working memory (WM) performance. Negative emotional distractors in particular lead to detrimental effects on WM. However, these associations have only been seen when distractors and items to maintain in WM are from the same sensory modality. In this study, we investigate cross-modal interference on WM. We invited 20 participants to complete a visual change-detection task, assessing visual WM (VWM), while hearing emotional (fearful) and neutral auditory distractors. Electrophysiological activity was recorded to measure contralateral delay activity (CDA) and auditory P2 event-related potentials (ERP), indexing WM maintenance and distractor salience respectively. At the behavioral level, fearful prosody didn't decrease significantly working memory accuracy, compared to neutral prosody. Regarding ERPs, fearful distractors evoked a greater P2 amplitude than neutral distractors. Correlations between the two ERP potentials indicated that P2 amplitude difference between the two types of prosody was associated with the difference in CDA amplitude for fearful and neutral trials. This association suggests that cognitive resources required to process fearful prosody detrimentally impact VWM maintenance. That result provides a piece of additional evidence that negative emotional stimuli produce greater interference than neutral stimuli and that the cognitive resources used to process stimuli from different modalities come from a common pool.

DLPFC controls the rapid neural response to visual threat: An ERP and rTMS study.

Individuals are faster at detecting threatening stimuli than neutral stimuli. While generally considered a rapid bottom-up response, this threat superiority effect is also modulated by top-down mechanisms known to rely on the dorsolateral prefrontal cortex (DLPFC). What remains unclear is whether the response is modulated only at later stages of processing, or whether rapid attention to threat itself is controlled in a top-down manner. To test this, we used repetitive transcranial magnetic stimulation (rTMS) to inhibit activity in the DLPFC, and measured EEG to index the immediate neural response to threat. Twenty participants attended two sessions where they performed a visual search task with threatening or neutral targets. Prior to this, they received 15 min of 1 Hz inhibitory or sham rTMS targeting the right DLPFC. We measured the impact of rTMS on the P1, a rapid visually-evoked potential that is modulated by attention. We found that threatening targets increased the amplitude of the P1 in the sham condition, but inhibition of the DLPFC abolished this increase. These results suggest that the neural signature of rapid attentional detection of threat, even at its earliest stage, is influenced in a top-down fashion by the right DLPFC.