Biology subjects

Gunseli, E.

Publications and source records attributed to Gunseli, E..

4 recordsLinked to original sources

bioRxiv2026

Mental Operations on Long-term Memory do not Require a Sustained Increase in Working Memory Engagement

Working memory (WM) is often assumed to play a stronger role in mental operations than in pure storage. However, much of the evidence comes from tasks using novel stimuli requiring active maintenance. Everyday cognition, in contrast, often involves operating on information retrieved from long-term memory (LTM), which may not always require sustained WM storage. Moreover, prior evidence for enhanced WM involvement relies on univariate measures, which cannot separate procedural demands of operations from representational strength of operation-relevant items. Here, we used EEG to test how WM supports mental operations on LTM. First, participants studied color-position associations. Then, on each trial, a color cue prompted retrieval of its associated position, followed by a novel position. Across blocks, participants either performed a mental operation to compute the positions' spatial midpoint or judged whether the probe matched one of the memory positions. Representations of task type and memory position were assessed using MVPA and inverted encoding models on alpha-band power, respectively. Task type was decoded throughout the trial, reflecting persistent task-set representations. In contrast, LTM position was represented in WM more strongly for integration than recognition early in the retention and operation periods, but these differences were transient. These findings challenge the view that mental operations inherently demand enhanced WM engagement: when information is available in LTM, increased WM involvement is transient, not sustained.

neuroscience↗

bioRxiv2024

Effects of context changes on memory reactivation

While the influence of context on long-term memory (LTM) is well-documented, its effects on the interaction between working memory (WM) and LTM remain less understood. In this study, we explored these interactions using a delayed match-to-sample task, where participants (6 Male, 16 Female) encountered the same target object across six consecutive trials, facilitating the transition from WM to LTM. During half of these target repetitions, the background color changed. We measured the WM storage of the target using the contralateral delay activity (CDA) in electroencephalography (EEG). Our results reveal that task-irrelevant context changes trigger the reactivation of long-term memories in WM. This reactivation may be attributed to content-context binding in WM and hippocampal pattern separation. Significance StatementUnderstanding the mechanisms of memory updating in response to changing contexts is vital because context plays a pivotal role in shaping long-term memories. This study demonstrates, for the first time, that an irrelevant context change triggers the reactivation of learned memories in visual working memory. This observation underscores the importance of multi-memory interactions during context updating. Challenging traditional memory models that postulate mandatory reactivation of long-term memories upon each use, our results instead reveal a selective reactivation process, especially during transitions to new environments. This finding elucidates the adaptive nature of memories and enhances our understanding of memory storage and retrieval processes.

neuroscience↗

bioRxiv2018

Dissecting the neural focus of attention reveals distinct processes for spatial attention and object-based storage in visual working memory

Complex cognition relies on both online representations in working memory (WM) said to reside in the focus of attention, and passive offline representations of related information. Here, we dissect the focus of attention by showing that distinct neural signals index the online storage of objects and sustained spatial attention. We recorded EEG activity during two tasks that employed identical stimulus displays while the relative demands for object storage and spatial attention varied. We found distinct delay-period signatures for an attention task (which only required spatial attention) and WM task (which invoked both spatial attention and object storage). Although both tasks required active maintenance of spatial information, only the WM task elicited robust contralateral delay activity that was sensitive to mnemonic load. Thus, we argue that the focus of attention is maintained via a collaboration between distinct processes for covert spatial orienting and object-based storage.

neuroscience↗

bioRxiv2018

Unattended but actively stored: EEG dynamics reveal a dissociation between selective attention and storage in working memory

Selective attention plays a prominent role in prioritizing information in working memory (WM), improving performance for attended representations. However, it remains unclear what the consequences of selection are for the maintenance of unattended WM representations, and whether this results in information loss. Here we tested the hypothesis that within WM, selectively attending to an item and the decision to stop storing other items involve independent mechanisms. We recorded EEG while participants performed a WM recall task in which the item most likely to be tested was cued retrospectively. By manipulating retro-cue reliability (i.e. the ratio of valid to invalid cue trials) we varied the incentive to retain uncued items. Contralateral alpha power suppression, a proxy for attention, indicated that, initially, the cued item was attended equally following high and low reliability cues, but attention was sustained throughout the delay period only after high reliability cues. Furthermore, contralateral delay activity (CDA), a proxy for storage, indicated that non-cued items were dropped sooner from WM after highly reliability cues than after cues with low reliability. These results show that attention and storage in WM are distinct processes that can behave differently depending on the relative importance of WM representations, as expressed in dissociable EEG signals.

neuroscience↗