Effects of load and emotional state on EEG alpha-band power and inter-site synchrony during a visual working memory task
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Effects of load and emotional state on EEG alpha-band power and inter-site synchrony during a visual working memory task Jessica Sanches Braga Figueira 1,2 & Isabel de Paula Antunes David 1 & Isabela Lobo 3 & Luiza Bonfim Pacheco 1 & Mirtes Garcia Pereira 1 & Leticia de Oliveira 1 & Andreas Keil 2
# The Psychonomic Society, Inc. 2020
Abstract Motivationally/emotionally engaging stimuli are strong competitors for the limited capacity of sensory and cognitive systems. Thus, they often act as distractors, interfering with performance in concurrent primary tasks. Keeping task-relevant information in focus while suppressing the impact of distracting stimuli is one of the functions of working memory (WM). Macroscopic brain oscillations in the alpha band (8–13 Hz) have recently been identified as a neural correlate of WM processing. Using electroencephalography, we examined the extent to which changes in alpha power and inter-site connectivity during a typical WM task are sensitive to load and emotional distraction. Participants performed a lateralized change-detection task with two levels of load (four vs. two items), which was preceded by naturalistic scenes rated either as unpleasant or neutral, acting as distractors. The results showed the expected parieto-occipital alpha reduction in the hemisphere contralateral to the WM task array, compared to the ipsilateral hemisphere, during the retention interval. Selectively heightened oscillatory coupling between frontal and occipital sensors was observed (1) during the retention interval as a function of load, and (2) upon the onset of the memory array, after viewing neutral compared to unpleasant distractors. At the end of the retention interval, we observed greater coupling during the unpleasant compared to the neutral condition. These findings are consistent with the notions that (1) representing more items in WM requires greater interconnectivity across cortical areas, and (2) unpleasant emotional distractors interfere with subsequent WM processing by disrupting processing during the encoding stage. Keywords Working memory . EEG . Alpha oscillations . Inter-site synchrony . Emotion
Introduction Working memory (WM) can be described as a set of cognitive processes that allow us to maintain a limited amount of goalrelevant information, even when this information is no longer present in the sensory environment (Baddeley, 2012; Cowan, 2001). In order to successfully access and manipulate WM content, these processes rely not only on maintaining and selecting information, but also on suppressing irrelevant and * Jessica Sanches Braga Figueira [email protected] 1
Laboratório de Neurofisiologia do Comportamento, Departamento de Fisiologia e Farmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
2
Center for the Study of Emotion and Attention, University of Florida, 3063 Long Leaf Rd, Gainesville, FL 32608, USA
3
Grupo de Psicobiologia, NUPEM, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
distracting items (Luria, Bal
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