EEG Signatures of Orienting Attention to Long-Term vs. Working Memory Contents
Dongyu Gong1,2 (firstname.lastname@example.org), Dejan Draschkow2, Anna C. Nobre1,2; 1Yale University, 2University of Oxford
Internal attention selects and prioritizes contents within memory representations to guide future behavior. Most studies have considered internal attention within working memory (WM), but selection and prioritization can also occur within long-term memory (LTM). The neural processes engaged by internal attention in LTM are poorly understood. To compare directly internal attention in LTM and WM, we recorded EEG signals from participants engaged in a task where they were presented with a four-placeholder array, featuring two locations for immediate working memory encoding and two associated with pre-learned long-term memory items. A brief delay after a color-based retrocue, participants reproduced the shape of the cued item. Multivariate pattern analysis was able to able to decode the memory domain of the cued item (WM vs. LTM) during the delay, suggesting that internal attention in LTM and WM is at least partially dissociable. Additional EEG and ERP markers also highlighted differences in selecting and prioritizing LTM and WM contents. Even though spatial attention was not strictly required by the task, orienting attention to WM items showed signs of spatial modulation (lateralized event-related potentials and 8-12 Hz alpha-power lateralization). In contrast, spatial modulations were not conspicuous for internal attention in LTM. Instead, non-lateralized theta power (3-7 Hz) was higher when selecting an LTM item. Our findings suggest that orienting attention to LTM contents involves different neural mechanisms compared to WM. Selecting an item in LTM, therefore, may not be contingent on reinstating a WM representation but instead rely on a different memory format.
Topic Area: ATTENTION: Other
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April 13–16 | 2024