The Contralateral Delay Activity Tracks the Sequential Loading of Objects into Visual Working Memory, Unlike Lateralized Alpha Oscillations

Visual working memory temporarily represents a continuous stream of task-relevant objects as we move through our environment performing tasks. Previous work has identified candidate neural mechanisms of visual working memory storage; however, we do not know which of these mechanisms enable the storage of objects as we sequentially encounter them in our environment. Here, we measured the contralateral delay activity (CDA) and lateralized alpha oscillations as human subjects were shown a series of objects that they needed to remember. The amplitude of CDA increased following the presentation of each to-be-remembered object, reaching asymptote at about three to four objects. In contrast, the concurrently measured lateralized alpha power remained constant with each additional object. Our results suggest that the CDA indexes the storage of objects in visual working memory, whereas lateralized alpha suppression indexes the focusing of attention on the to-be-remembered objects.

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

Journal of Neurophysiology ◽

10.1152/jn.00230.2021 ◽

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.

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Contralateral Delay Activity Tracks Fluctuations in Working Memory Performance

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01233 ◽

2018 ◽

Vol 30 (9) ◽

pp. 1229-1240 ◽

Cited By ~ 32

Author(s):

Kirsten C. S. Adam ◽

Matthew K. Robison ◽

Edward K. Vogel

Keyword(s):

Working Memory ◽

Individual Differences ◽

Memory Load ◽

Memory Performance ◽

Memory Task ◽

Memory Storage ◽

Alpha Power ◽

Working Memory Load ◽

Contralateral Delay Activity ◽

Trial Performance

Neural measures of working memory storage, such as the contralateral delay activity (CDA), are powerful tools in working memory research. CDA amplitude is sensitive to working memory load, reaches an asymptote at known behavioral limits, and predicts individual differences in capacity. An open question, however, is whether neural measures of load also track trial-by-trial fluctuations in performance. Here, we used a whole-report working memory task to test the relationship between CDA amplitude and working memory performance. If working memory failures are due to decision-based errors and retrieval failures, CDA amplitude would not differentiate good and poor performance trials when load is held constant. If failures arise during storage, then CDA amplitude should track both working memory load and trial-by-trial performance. As expected, CDA amplitude tracked load (Experiment 1), reaching an asymptote at three items. In Experiment 2, we tracked fluctuations in trial-by-trial performance. CDA amplitude was larger (more negative) for high-performance trials compared with low-performance trials, suggesting that fluctuations in performance were related to the successful storage of items. During working memory failures, participants oriented their attention to the correct side of the screen (lateralized P1) and maintained covert attention to the correct side during the delay period (lateralized alpha power suppression). Despite the preservation of attentional orienting, we found impairments consistent with an executive attention theory of individual differences in working memory capacity; fluctuations in executive control (indexed by pretrial frontal theta power) may be to blame for storage failures.

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F187. Pre-Stimulus Alpha Power and Contralateral Delay Activity During Visual Working Memory in First Episode Schizophrenia

Biological Psychiatry ◽

10.1016/j.biopsych.2019.03.724 ◽

2019 ◽

Vol 85 (10) ◽

pp. S285-S286

Author(s):

Brian Coffman ◽

Tim Murphy ◽

Gretchen Haas ◽

Carl Olson ◽

Raymond Y. Cho ◽

...

Keyword(s):

Working Memory ◽

Visual Working Memory ◽

First Episode ◽

Alpha Power ◽

Contralateral Delay Activity ◽

First Episode Schizophrenia

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Impact of Experimental Modulation of EEG Alpha Power on Visual Working Memory Storage in Healthy Participants

Biological Psychiatry ◽

10.1016/j.biopsych.2020.02.1030 ◽

2020 ◽

Vol 87 (9) ◽

pp. S403 ◽

Cited By ~ 1

Author(s):

Molly Erickson ◽

Dillon Smith ◽

Laura Crespo ◽

Steven Silverstein

Keyword(s):

Working Memory ◽

Visual Working Memory ◽

Memory Storage ◽

Alpha Power ◽

Eeg Alpha ◽

Healthy Participants

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Contralateral Delay Activity Indexes Working Memory Storage, Not the Current Focus of Spatial Attention

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01271 ◽

2018 ◽

Vol 30 (8) ◽

pp. 1185-1196 ◽

Cited By ~ 18

Author(s):

Tobias Feldmann-Wüstefeld ◽

Edward K. Vogel ◽

Edward Awh

Keyword(s):

Working Memory ◽

Spatial Attention ◽

Visual Working Memory ◽

Memory Load ◽

Alternative Hypothesis ◽

Relevant Information ◽

Alternative Interpretation ◽

Memory Storage ◽

Probe Display ◽

Contralateral Delay Activity

Contralateral delay activity (CDA) has long been argued to track the number of items stored in visual working memory (WM). Recently, however, Berggren and Eimer [Berggren, N., & Eimer, M. Does contralateral delay activity reflect working memory storage or the current focus of spatial attention within visual working memory? Journal of Cognitive Neuroscience, 28, 2003–2020, 2016] proposed the alternative hypothesis that the CDA tracks the current focus of spatial attention instead of WM storage. This hypothesis was based on the finding that, when two successive arrays of memoranda were placed in opposite hemifields, CDA amplitude was primarily determined by the position and number of items in the second display, not the total memory load across both displays. Here, we considered the alternative interpretation that participants dropped the first array from WM when they encoded the second array because the format of the probe display was spatially incompatible with the initial sample display. In this case, even if the CDA indexes active storage rather than spatial attention, CDA activity would be determined by the second array. We tested this idea by directly manipulating the spatial compatibility of sample and probe displays. With spatially incompatible displays, we replicated Berggren and Eimer's findings. However, with spatially compatible displays, we found clear evidence that CDA activity tracked the full storage load across both arrays, in line with a WM storage account of CDA activity. We propose that expectations of display compatibility influenced whether participants viewed the arrays as parts of a single extended event or two independent episodes. Thus, these findings raise interesting new questions about how event boundaries may shape the interplay between passive and active representations of task-relevant information.

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Contralateral delay activity reveals dimension-based attentional orienting to locations in visual working memory

Attention Perception & Psychophysics ◽

10.3758/s13414-014-0636-0 ◽

2014 ◽

Vol 76 (3) ◽

pp. 655-662 ◽

Cited By ~ 11

Author(s):

Thomas Töllner ◽

Kathrin C. J. Eschmann ◽

Tessa Rusch ◽

Hermann J. Müller

Keyword(s):

Working Memory ◽

Visual Working Memory ◽

Attentional Orienting ◽

Contralateral Delay Activity

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Fear not! Anxiety biases attentional enhancement of threat without impairing working memory filtering

10.31234/osf.io/rn4fa ◽

2019 ◽

Cited By ~ 1

Author(s):

Christine Salahub ◽

Stephen Emrich

Keyword(s):

Working Memory ◽

Visual Working Memory ◽

State Anxiety ◽

Attentional Control ◽

Event Related Potentials ◽

Memory Storage ◽

Attentional Biases ◽

Related Potentials ◽

Filtering Efficiency ◽

Memory Resources

Individuals with anxiety have attentional biases toward threat-related distractors. This deficit in attentional control has been shown to impact visual working memory (VWM) filtering efficiency, as anxious individuals inappropriately store threatening distractors in VWM. It remains unclear, however, whether this mis-allocation of memory resources is due to inappropriate attentional enhancement of threatening distractors, or to a failure in suppression. Here, we used a systematically lateralized VWM task with fearful and neutral faces to examine event-related potentials related to attentional selection (N2pc), suppression (PD), and working memory maintenance (CDA). We found that state anxiety correlated with attentional enhancement of threat-related distractors, such that more anxious individuals had larger N2pc amplitudes toward fearful distractors than neutral distractors. However, there was no correlation between anxiety and memory storage of fearful distractors (CDA). These findings demonstrate that anxiety biases attention toward fearful distractors, but that this bias does not always guarantee increased memory storage of threat-related distractors.

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