scholarly journals Interval between two sequential arrays determines their storage state in visual working memory

2020 ◽  
Author(s):  
Ziyuan Li ◽  
Jiafeng Zhang ◽  
Tengfei Liang ◽  
Chaoxiong Ye ◽  
Qiang Liu
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Visual Information ◽  
Active State ◽  
Passive State ◽  
Dynamic Nature ◽  
Retention Period ◽  
Memory Representations ◽  
Interval Condition ◽  
First Time

AbstractThe visual information can be stored as either “active” representations in the active state or “activity-silent” representations in the passive state during the retention period in visual working memory (VWM). Catering to the dynamic nature of visual world, we explored how the temporally dynamic visual input was stored in VWM. In the current study, the memory arrays were presented sequentially, and the contralateral delay activity (CDA), an electrophysiological measure, was used to identify whether the memory representations were transferred into the passive state. Participants were instructed to encode two sequential arrays and retrieve them respectively, with two conditions of interval across the two arrays: 400ms and 800ms. These results provided strong evidence for the state-separated storage of two sequential arrays in different neural states if the interval between them was long enough, and the concurrent storage of them in the active state if the interval was relatively short. This conclusion was valid only when the participants encountered the task for the first time. Once participants have formed their mindset, they would apply the same storage mode to the subsequently extended or shortened interval condition.

scholarly journals Does perceptual grouping improve visuospatial working memory? Optimized processing or encoding bias

2021 ◽  
Author(s):  
Antonio Prieto ◽  
Vanesa Peinado ◽  
Julia Mayas
Keyword(s):  
Working Memory ◽  
Change Detection ◽  
Visual Working Memory ◽  
Visual Information ◽  
Detection Accuracy ◽  
Visuospatial Working Memory ◽  
Gestalt Grouping ◽  
Color Similarity ◽  
Automatic Encoding ◽  
Change Detection Performance

AbstractVisual working memory has been defined as a system of limited capacity that enables the maintenance and manipulation of visual information. However, some perceptual features like Gestalt grouping could improve visual working memory effectiveness. In two different experiments, we aimed to explore how the presence of elements grouped by color similarity affects the change detection performance of both, grouped and non-grouped items. We combined a change detection task with a retrocue paradigm in which a six item array had to be remembered. An always valid, variable-delay retrocue appeared in some trials during the retention interval, either after 100 ms (iconic-trace period) or 1400 ms (working memory period), signaling the location of the probe. The results indicated that similarity grouping biased the information entered into the visual working memory, improving change detection accuracy only for previously grouped probes, but hindering change detection for non-grouped probes in certain conditions (Exp. 1). However, this bottom-up automatic encoding bias was overridden when participants were explicitly instructed to ignore grouped items as they were irrelevant for the task (Exp. 2).

Greater Visual Working Memory Capacity for Visually Matched Stimuli When They Are Perceived as Meaningful

2021 ◽  
Vol 33 (5) ◽  
pp. 902-918 ◽  
Author(s):  
Isabel E. Asp ◽  
Viola S. Störmer ◽  
Timothy F. Brady
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Visual Information ◽  
Memory Performance ◽  
Working Memory Capacity ◽  
Visual Complexity ◽  
Memory Capacity ◽  
Subjective Perception ◽  
Neural Delay ◽  
Meaningful Stimuli

Abstract Almost all models of visual working memory—the cognitive system that holds visual information in an active state—assume it has a fixed capacity: Some models propose a limit of three to four objects, where others propose there is a fixed pool of resources for each basic visual feature. Recent findings, however, suggest that memory performance is improved for real-world objects. What supports these increases in capacity? Here, we test whether the meaningfulness of a stimulus alone influences working memory capacity while controlling for visual complexity and directly assessing the active component of working memory using EEG. Participants remembered ambiguous stimuli that could either be perceived as a face or as meaningless shapes. Participants had higher performance and increased neural delay activity when the memory display consisted of more meaningful stimuli. Critically, by asking participants whether they perceived the stimuli as a face or not, we also show that these increases in visual working memory capacity and recruitment of additional neural resources are because of the subjective perception of the stimulus and thus cannot be driven by physical properties of the stimulus. Broadly, this suggests that the capacity for active storage in visual working memory is not fixed but that more meaningful stimuli recruit additional working memory resources, allowing them to be better remembered.

A direct neural measure of variable precision representations in visual working memory

2021 ◽  
Author(s):  
Christian Merkel ◽  
Mandy Viktoria Bartsch ◽  
Mircea A Schoenfeld ◽  
Anne-Katrin Vellage ◽  
Notger G Müller ◽  
...  
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Recall Performance ◽  
Human Subjects ◽  
Item Information ◽  
Estimation Task ◽  
Active Representation ◽  
Contralateral Delay Activity ◽  
Memory Representations ◽  
Precision Estimation

Visual working memory (VWM) is an active representation enabling the manipulation of item information even in the absence of visual input. A common way to investigate VWM is to analyze the performance at later recall. This approach, however, leaves uncertainties about whether the variation of recall performance is attributable to item encoding and maintenance or to the testing of memorized information. Here, we record the contralateral delay activity (CDA) - an established electrophysiological measure of item storage and maintenance - in human subjects performing a delayed orientation precision estimation task. This allows us to link the fluctuation of recall precision directly to the process of item encoding and maintenance. We show that for two sequentially encoded orientation items, the CDA amplitude reflects the precision of orientation recall of both items, with higher precision being associated with a larger amplitude. Furthermore, we show that the CDA amplitude for each item varies independently from each other, suggesting that the precision of memory representations fluctuates independently.

scholarly journals The Neural Codes Underlying Internally Generated Representations in Visual Working Memory

2021 ◽  
pp. 1-16
Author(s):  
Qing Yu ◽  
Bradley R. Postle
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Subjective Experience ◽  
Neural Representation ◽  
Delayed Recall ◽  
Early Visual Cortex ◽  
Memory Representations ◽  
Internal Sources ◽  
Scaling Analyses

Abstract Humans can construct rich subjective experience even when no information is available in the external world. Here, we investigated the neural representation of purely internally generated stimulus-like information during visual working memory. Participants performed delayed recall of oriented gratings embedded in noise with varying contrast during fMRI scanning. Their trialwise behavioral responses provided an estimate of their mental representation of the to-be-reported orientation. We used multivariate inverted encoding models to reconstruct the neural representations of orientation in reference to the response. We found that response orientation could be successfully reconstructed from activity in early visual cortex, even on 0% contrast trials when no orientation information was actually presented, suggesting the existence of a purely internally generated neural code in early visual cortex. In addition, cross-generalization and multidimensional scaling analyses demonstrated that information derived from internal sources was represented differently from typical working memory representations, which receive influences from both external and internal sources. Similar results were also observed in intraparietal sulcus, with slightly different cross-generalization patterns. These results suggest a potential mechanism for how externally driven and internally generated information is maintained in working memory.

scholarly journals Visual working memory representations are shifted toward irrelevant features of distractors in intervening visual search tasks

2019 ◽  
Vol 19 (10) ◽  
pp. 311b
Author(s):  
Zachary A Lively ◽  
Gavin JP Ng ◽  
Simona Buetti ◽  
Alejandro Lleras
Keyword(s):  
Working Memory ◽  
Visual Search ◽  
Visual Working Memory ◽  
Search Tasks ◽  
Memory Representations

Manifold Visual Working Memory

2020 ◽  
pp. 311-332
Author(s):  
Nicole Hakim ◽  
Edward Awh ◽  
Edward K. Vogel
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Neural Activity ◽  
Long Term Memory ◽  
Term Memory ◽  
Memory Representations ◽  
Latent Representations ◽  
Definition Of ◽  
Spatial Locations

Visual working memory allows us to maintain information in mind for use in ongoing cognition. Research on visual working memory often characterizes it within the context of its interaction with long-term memory (LTM). These embedded-processes models describe memory representations as existing in three potential states: inactivated LTM, including all representations stored in LTM; activated LTM, latent representations that can quickly be brought into an active state due to contextual priming or recency; and the focus of attention, an active but sharply limited state in which only a small number of items can be represented simultaneously. This chapter extends the embedded-processes framework of working memory. It proposes that working memory should be defined operationally based on neural activity. By defining working memory in this way, the important theoretical distinction between working memory and LTM is maintained, while still acknowledging that they operate together. It is additionally proposed that active working memory should be further subdivided into at least two subcomponent processes that index item-based storage and currently prioritized spatial locations. This fractionation of working memory is based on recent research that has found that the maintenance of information distinctly relies on item-based representations as well as prioritization of spatial locations. It is hoped that this updated framework of the definition of working memory within the embedded-processes model provides further traction for understanding how we maintain information in mind.

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