Dongyu Gong

Dongyu Gong

PhD Student at Yale University

Presentations

EEG signatures of orienting attention to long-term vs. working memory contents

April 13, 2024

Talk, 2024 Cognitive Neuroscience Society Annual Meeting, Toronto, Canada

Attention can be directed towards internally generated representations of the past, a process known as internal attention. Internal attention can operate over contents of both working memory (WM) and long-term memory (LTM)**, **but far less is known in terms of the neural signatures when orienting attention in LTM compared to WM. To answer this question, we recorded EEG signals from participants engaged in a behavioral task where retrospective attention cues prioritized either a WM item that switched features from trial to trial, or an LTM item that had been previously memorized. Following a brief delay, participants reproduced the cued item. Using multivariate pattern analysis, we were able to decode the timescale of the cued item (WM vs. LTM) during the delay. Furthermore, left vs. right items were better decodable for WM, whereas LTM representations seemed to show less lateralization. Event-related potentials revealed higher contralateral responses at posterior sites for WM items, but no such lateralization for LTM items. Time-frequency analysis indicated alpha power (8-12 Hz) lateralization during a WM delay but not LTM. However, non-lateralized theta power (3-7 Hz) is found to be higher during an LTM delay compared to WM, hinting at distinct retrieval processes for LTM. To sum up, our findings suggest that orienting attention to LTM contents involves different neural mechanisms compared to WM. Selecting an item in LTM does not necessarily bring it back to the same state of a WM item, indicating potentially dissociable representational formats for WM and LTM contents.

Dissociable neural processes during attentional selection within working memory and long-term memory

November 11, 2023

Talk, 2023 Society for Neuroscience Annual Meeting, Washington D.C., United States

Research has increasingly emphasized the ability to orient attention selectively to prioritise internal contents for retrieval - in both workingmemory (WM) and long-term memory (LTM). However, little is known about the potential degree of overlap between mechanisms for internal attention in WM and LTM. We developed a task for comparing shifts of internal attention in WM and LTM for retrieving equivalent stimulus attributes. Eye tracking and EEG recordings from human participants (N = 30) tracked oculomotor and neural signals triggered by retrospective attention cues (retrocues) that prioritised object features of WM or LTM items on a trial-by-trial basis. The eye-tracking results confirmed our recent observation that gaze biases toward the attended item were more pronounced in WM than LTM. The EEG data revealed striking differences in neural processes following retrocues prioritising WM and LTM items. Replicating previous findings, transient lateralization of alpha power (8-12Hz) at posterior sites occurred for shifts of attention in WM, but no such effects occurred for attention within LTM. Instead, frontal modulation oftheta power (4-8 Hz) occurred during shifts of attention in LTM but not in WM. Further dissociable markers of internal shifts of attention in WM and LTM were observed in the event-related potentials. Our findings show that the robust consequences of orienting selective attention in WM and LTM occur through different routes, thus also providing valuable insights into the long-debated relationship between these two memory systems.

Focusing attention in long-term and working memory improves recall and guides perception

May 19, 2023

Poster, 2023 Vision Sciences Society Annual Meeting, St Pete Beach, United States

Attention can be directed not only to sensory stimuli from the external environment but also to internal representations in memory. While attentional selection in working memory (WM) has been widely studied, we know less about how we focus on contents within long-term memory (LTM). In two experiments, we directly compared the consequences of selecting items in LTM and WM, examining influences on subsequent recall and perception. Participants first learned the features of two LTM items during a learning phase. In the subsequent phase, participants viewed two items with features different from the LTM items and encoded these into WM. After a delay, a retrocue informed participants which item they should select from either the LTM or WM items or, was uninformative. On half of the trials, participants were prompted to recall the retrocued item. Critically, on the other trials, participants performed a perceptual discrimination task on a briefly presented and masked sensory array unrelated to the memory contents. The item to discriminate appeared equiprobably at the four locations, thereby overlapping with retrocued LTM or WM locations on 25% of the trials. In both experiments, informative retrocues facilitated recall speed for LTM and WM contents. Retrocuing items in LTM and WM also incidentally improved perceptual discrimination for visual items coinciding with the location of retrocued items, despite retrocues having no sensory predictive value. Although the behavioural benefits showed a similar pattern, eye tracking suggested functionally dissociable mechanisms for orienting attention in LTM and WM. Significant gaze biases followed retrocues indicating items in WM but not in LTM. Overall, our study introduces an experimental approach for comparing the processes and consequences of attentional orienting in LTM and WM. We observe memory and perceptual benefits for attentional orienting in both memory domains but through partially dissociable mechanisms.

Selecting and Prioritising Contents in Working and Long-term Memory Guides Recall and Perception

July 26, 2022

Poster presentation, 2022 Gordon Research Conference on Neurobiology of Cognition, Maine, United States

Although theoretical models have highlighted the close relation between long-term memory (LTM) and attention, we have little understanding of how the processes of orienting, selecting, and prioritising relevant contents in long-term memory unfold. Here we build on findings and methods developed to study internal selective attention in working memory (WM), to show that selection and prioritisation of contents from long-term memory improves recall of stored information and guides perception in a secondary task. We developed a task in which participants hold separate colour-location combinations in LTM and WM. Subsequently, a colour cue (‘retro-cue’) would indicate the identity of the target that would be probed in a memory recall task after a short delay. Critically, in half of the trials, following the delay participants would instead have to complete a perceptual detection task in which stimuli unrelated to memory contents briefly flash on the screen. Our results show that selection and prioritisation of contents from both long-term and working memory not only improve memory recall, but also enhance perceptual sensitivity when the probed location in the perception task is matched with the currently prioritised location in LTM/WM. Our method of studying internal selective attention in long-term memory opens the door to exploring our flexible and adaptive usage of memories in service of behaviour.We reported how working memory (WM) and long-term memory (LTM) traces can guide external spatial attention when retro-cued before a perception task, and how timing has a critical influence on the guidance from WM and LTM.

Guiding Perception by Memories of Different Timescales

June 16, 2022

Poster presentation, 2022 Oxford-MRC DTP Symposium, Oxford

We reported how working memory (WM) and long-term memory (LTM) traces can guide external spatial attention when retro-cued before a perception task, and how timing has a critical influence on the guidance from WM and LTM.

The effect of distractor saliency on attentional capture

November 15, 2019

Poster presentation, 60th Annual Meeting of the Psychonomic Society, Montreal, Canada

More information here

Theeuwes (1991, 1992) found that a salient but task-irrelevant color singleton would increase the response time to the target form singleton, and he proposed that this was because the salient distractor captured attention before it was shifted to the target, which is known as the automatic capture hypothesis. He further suggested the relative saliency of the color singleton would determine whether it could capture attention, but so far there hasn’t been any experiments revealing specifically how different distractor saliency conditions on a continuous spectrum would have an effect on attentional capture. In this research, we examined this question within multiple attention-guiding dimensions, including color, size and orientation (Wolfe & Horowitz, 2004).