1
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Bays PM, Schneegans S, Ma WJ, Brady TF. Representation and computation in visual working memory. Nat Hum Behav 2024; 8:1016-1034. [PMID: 38849647 DOI: 10.1038/s41562-024-01871-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 03/22/2024] [Indexed: 06/09/2024]
Abstract
The ability to sustain internal representations of the sensory environment beyond immediate perception is a fundamental requirement of cognitive processing. In recent years, debates regarding the capacity and fidelity of the working memory (WM) system have advanced our understanding of the nature of these representations. In particular, there is growing recognition that WM representations are not merely imperfect copies of a perceived object or event. New experimental tools have revealed that observers possess richer information about the uncertainty in their memories and take advantage of environmental regularities to use limited memory resources optimally. Meanwhile, computational models of visuospatial WM formulated at different levels of implementation have converged on common principles relating capacity to variability and uncertainty. Here we review recent research on human WM from a computational perspective, including the neural mechanisms that support it.
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Affiliation(s)
- Paul M Bays
- Department of Psychology, University of Cambridge, Cambridge, UK
| | | | - Wei Ji Ma
- Center for Neural Science and Department of Psychology, New York University, New York, NY, USA
| | - Timothy F Brady
- Department of Psychology, University of California, San Diego, La Jolla, CA, USA.
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2
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Duan Z, Curtis CE. Visual working memories are abstractions of percepts. eLife 2024; 13:RP94191. [PMID: 38819426 PMCID: PMC11147505 DOI: 10.7554/elife.94191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024] Open
Abstract
During perception, decoding the orientation of gratings depends on complex interactions between the orientation of the grating, aperture edges, and topographic structure of the visual map. Here, we aimed to test how aperture biases described during perception affect working memory (WM) decoding. For memoranda, we used gratings multiplied by radial and angular modulators to generate orthogonal aperture biases for identical orientations. Therefore, if WM representations are simply maintained sensory representations, they would have similar aperture biases. If they are abstractions of sensory features, they would be unbiased and the modulator would have no effect on orientation decoding. Neural patterns of delay period activity while maintaining the orientation of gratings with one modulator (e.g. radial) were interchangeable with patterns while maintaining gratings with the other modulator (e.g. angular) in visual and parietal cortex, suggesting that WM representations are insensitive to aperture biases during perception. Then, we visualized memory abstractions of stimuli using models of visual field map properties. Regardless of aperture biases, WM representations of both modulated gratings were recoded into a single oriented line. These results provide strong evidence that visual WM representations are abstractions of percepts, immune to perceptual aperture biases, and compel revisions of WM theory.
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Affiliation(s)
- Ziyi Duan
- Department of Psychology, New York UniversityNew YorkUnited States
| | - Clayton E Curtis
- Department of Psychology, New York UniversityNew YorkUnited States
- Center for Neural Science, New York UniversityNew YorkUnited States
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3
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Yiling Y, Klon-Lipok J, Shapcott K, Lazar A, Singer W. Dynamic fading memory and expectancy effects in the monkey primary visual cortex. Proc Natl Acad Sci U S A 2024; 121:e2314855121. [PMID: 38354261 PMCID: PMC10895277 DOI: 10.1073/pnas.2314855121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/10/2024] [Indexed: 02/16/2024] Open
Abstract
In order to investigate the involvement of the primary visual cortex (V1) in working memory (WM), parallel, multisite recordings of multi-unit activity were obtained from monkey V1 while the animals performed a delayed match-to-sample (DMS) task. During the delay period, V1 population firing rate vectors maintained a lingering trace of the sample stimulus that could be reactivated by intervening impulse stimuli that enhanced neuronal firing. This fading trace of the sample did not require active engagement of the monkeys in the DMS task and likely reflects the intrinsic dynamics of recurrent cortical networks in lower visual areas. This renders an active, attention-dependent involvement of V1 in the maintenance of WM contents unlikely. By contrast, population responses to the test stimulus depended on the probabilistic contingencies between sample and test stimuli. Responses to tests that matched expectations were reduced which agrees with concepts of predictive coding.
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Affiliation(s)
- Yang Yiling
- Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main60528, Germany
| | - Johanna Klon-Lipok
- Max Planck Institute for Brain Research, Frankfurt am Main60438, Germany
| | - Katharine Shapcott
- Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main60528, Germany
| | - Andreea Lazar
- Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main60528, Germany
| | - Wolf Singer
- Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main60528, Germany
- Max Planck Institute for Brain Research, Frankfurt am Main60438, Germany
- Frankfurt Institute for Advanced Studies, Frankfurt am Main60438, Germany
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4
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Weber S, Christophel T, Görgen K, Soch J, Haynes J. Working memory signals in early visual cortex are present in weak and strong imagers. Hum Brain Mapp 2024; 45:e26590. [PMID: 38401134 PMCID: PMC10893972 DOI: 10.1002/hbm.26590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/06/2023] [Accepted: 12/29/2023] [Indexed: 02/26/2024] Open
Abstract
It has been suggested that visual images are memorized across brief periods of time by vividly imagining them as if they were still there. In line with this, the contents of both working memory and visual imagery are known to be encoded already in early visual cortex. If these signals in early visual areas were indeed to reflect a combined imagery and memory code, one would predict them to be weaker for individuals with reduced visual imagery vividness. Here, we systematically investigated this question in two groups of participants. Strong and weak imagers were asked to remember images across brief delay periods. We were able to reliably reconstruct the memorized stimuli from early visual cortex during the delay. Importantly, in contrast to the prediction, the quality of reconstruction was equally accurate for both strong and weak imagers. The decodable information also closely reflected behavioral precision in both groups, suggesting it could contribute to behavioral performance, even in the extreme case of completely aphantasic individuals. Our data thus suggest that working memory signals in early visual cortex can be present even in the (near) absence of phenomenal imagery.
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Affiliation(s)
- Simon Weber
- Bernstein Center for Computational Neuroscience Berlin and Berlin Center for Advanced NeuroimagingCharité ‐ Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
- Research Training Group “Extrospection” and Berlin School of Mind and Brain, Humboldt‐Universität zu BerlinBerlinGermany
- Research Cluster of Excellence “Science of Intelligence”Technische Universität BerlinBerlinGermany
| | - Thomas Christophel
- Bernstein Center for Computational Neuroscience Berlin and Berlin Center for Advanced NeuroimagingCharité ‐ Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
- Department of PsychologyHumboldt‐Universität zu BerlinBerlinGermany
| | - Kai Görgen
- Bernstein Center for Computational Neuroscience Berlin and Berlin Center for Advanced NeuroimagingCharité ‐ Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
- Research Cluster of Excellence “Science of Intelligence”Technische Universität BerlinBerlinGermany
| | - Joram Soch
- Bernstein Center for Computational Neuroscience Berlin and Berlin Center for Advanced NeuroimagingCharité ‐ Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
- Institute of Psychology, Otto von Guericke University MagdeburgMagdeburgGermany
| | - John‐Dylan Haynes
- Bernstein Center for Computational Neuroscience Berlin and Berlin Center for Advanced NeuroimagingCharité ‐ Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt‐Universität zu BerlinBerlinGermany
- Research Training Group “Extrospection” and Berlin School of Mind and Brain, Humboldt‐Universität zu BerlinBerlinGermany
- Research Cluster of Excellence “Science of Intelligence”Technische Universität BerlinBerlinGermany
- Department of PsychologyHumboldt‐Universität zu BerlinBerlinGermany
- Collaborative Research Center “Volition and Cognitive Control”Technische Universität DresdenDresdenGermany
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5
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Chunharas C, Hettwer MD, Wolff MJ, Rademaker RL. A gradual transition from veridical to categorical representations along the visual hierarchy during working memory, but not perception. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.18.541327. [PMID: 37292916 PMCID: PMC10245673 DOI: 10.1101/2023.05.18.541327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The ability to stably maintain visual information over brief delays is central to cognitive functioning. One possible way to achieve robust working memory maintenance is by having multiple concurrent mnemonic representations across multiple cortical loci. For example, early visual cortex might contribute to storage by representing information in a "sensory-like" format, while intraparietal sulcus uses a format transformed away from sensory driven responses. As an explicit test of mnemonic code transformations along the visual hierarchy, we quantitatively modeled the progression of veridical-to-categorical orientation representations in human participants. Participants directly viewed, or held in mind, an oriented grating pattern, and the similarity between fMRI activation patterns for different orientations was calculated throughout retinotopic cortex. During direct perception, similarity was clustered around cardinal orientations, while during working memory the obliques were represented more similarly. We modeled these similarity patterns based on the known distribution of orientation information in the natural world: The "veridical" model uses an efficient coding framework to capture hypothesized representations during visual perception. The "categorical" model assumes that different "psychological distances" between orientations result in orientation categorization relative to cardinal axes. During direct perception, the veridical model explained the data well in early visual areas, while the categorical model did worse. During working memory, the veridical model only explained some of the data, while the categorical model gradually gained explanatory power for increasingly anterior retinotopic regions. These findings suggest that directly viewed images are represented veridically, but once visual information is no longer tethered to the sensory world, there is a gradual progression to more categorical mnemonic formats along the visual hierarchy.
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Affiliation(s)
- Chaipat Chunharas
- Department of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, Bangkok, Thailand
| | - Meike D Hettwer
- Max Planck School of Cognition, Max Planck Institute of Human Cognitive and Brain Sciences, Leipzig, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Michael J Wolff
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with the Max Planck Society, Frankfurt, Germany
| | - Rosanne L Rademaker
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with the Max Planck Society, Frankfurt, Germany
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6
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Deutsch P, Czoschke S, Fischer C, Kaiser J, Bledowski C. Decoding of Working Memory Contents in Auditory Cortex Is Not Distractor-Resistant. J Neurosci 2023; 43:3284-3293. [PMID: 36944488 PMCID: PMC10162453 DOI: 10.1523/jneurosci.1890-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 02/16/2023] [Accepted: 03/08/2023] [Indexed: 03/23/2023] Open
Abstract
Working memory enables the temporary storage of relevant information in the service of behavior. Neuroimaging studies have suggested that sensory cortex is involved in maintaining contents in working memory. This raised the question of how sensory regions maintain memory representations during the exposure to distracting stimuli. Multivariate pattern analysis of fMRI signals in visual cortex has shown that the contents of visual working memory could be decoded concurrently with passively viewed distractors. The present fMRI study tested whether this finding extends to auditory working memory and to active distractor processing. We asked participants to memorize the pitch of a target sound and to compare it with a probe sound presented after a 13 s delay period. In separate conditions, we compared a blank delay phase (no distraction) with either passive listening to, or active processing of, an auditory distractor presented throughout the memory delay. Consistent with previous reports, pitch-specific memory information could be decoded in auditory cortex during the delay in trials without distraction. In contrast, decoding of target sounds in early auditory cortex dropped to chance level during both passive and active distraction. This was paralleled by memory performance decrements under distraction. Extending the analyses beyond sensory cortex yielded some evidence for memory content-specific activity in inferior frontal and superior parietal cortex during active distraction. In summary, while our findings question the involvement of early auditory cortex in the maintenance of distractor-resistant working memory contents, further research should elucidate the role of hierarchically higher regions.SIGNIFICANCE STATEMENT Information about sensory features held in working memory can be read out from hemodynamic activity recorded in human sensory cortices. Moreover, visual cortex can in parallel store visual content and process newly incoming, task-irrelevant visual input. The present study investigated the role of auditory cortex for working memory maintenance under distraction. While memorized sound frequencies could be decoded in auditory cortex in the absence of distraction, auditory distraction during the delay phase impaired memory performance and prevented decoding of information stored in working memory. Apparently, early auditory cortex is not sufficient to represent working memory contents under distraction that impairs performance. However, exploratory analyses indicated that, under distraction, higher-order frontal and parietal regions might contribute to content-specific working memory storage.
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Affiliation(s)
- Philipp Deutsch
- Institute of Medical Psychology, Medical Faculty, Goethe University, Frankfurt am Main 60528, Germany
- Brain Imaging Center, Medical Faculty, Goethe University, Frankfurt am Main, 60528, Germany
| | - Stefan Czoschke
- Institute of Medical Psychology, Medical Faculty, Goethe University, Frankfurt am Main 60528, Germany
- Brain Imaging Center, Medical Faculty, Goethe University, Frankfurt am Main, 60528, Germany
| | - Cora Fischer
- Institute of Medical Psychology, Medical Faculty, Goethe University, Frankfurt am Main 60528, Germany
- Brain Imaging Center, Medical Faculty, Goethe University, Frankfurt am Main, 60528, Germany
| | - Jochen Kaiser
- Institute of Medical Psychology, Medical Faculty, Goethe University, Frankfurt am Main 60528, Germany
- Brain Imaging Center, Medical Faculty, Goethe University, Frankfurt am Main, 60528, Germany
| | - Christoph Bledowski
- Institute of Medical Psychology, Medical Faculty, Goethe University, Frankfurt am Main 60528, Germany
- Brain Imaging Center, Medical Faculty, Goethe University, Frankfurt am Main, 60528, Germany
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7
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Phylactou P, Shimi A, Konstantinou N. Causal evidence for the role of the sensory visual cortex in visual short-term memory maintenance. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230321. [PMID: 37090966 PMCID: PMC10113812 DOI: 10.1098/rsos.230321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 03/27/2023] [Indexed: 05/03/2023]
Abstract
The role of the sensory visual cortex during visual short-term memory (VSTM) remains controversial. This controversy is possibly due to methodological issues in previous attempts to investigate the effects of transcranial magnetic stimulation (TMS) on VSTM. The aim of this study was to use TMS, while covering previous methodological deficits. Sixty-four young adults were recruited to participate in two experiments (Experiment 1: n = 36; Experiment 2: n = 28) using a VSTM orientation change-detection task under TMS. Monocular vision was ensured using red-blue goggles combined with red-blue stimuli. Double-pulse TMS was delivered at different times (Experiment 1: 0, 200 or 1000 ms; Experiment 2: 200, 1000 ms) during a 2 s maintenance phase, on one side of the occipital hemisphere. In Experiment 2, a sham TMS condition was introduced. Decreased detection sensitivity (d') in the ipsilateral occipital hemisphere to visual hemifield, and in the real TMS (compared with sham TMS) condition indicated inhibitory TMS effects, and thus, a causal involvement of the sensory visual cortex during early (200 ms) and late (1000 ms) maintenance in VSTM. These findings are aligned with sensory recruitment, which proposes that both perceptual and memory processes rely upon the same neural substrates in the sensory visual cortex. The methods used in this study were preregistered and had received in-principle acceptance on 6 June 2022 (Stage 1 protocol can be found in: https://doi.org/10.17605/OSF.IO/EMPDT).
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Affiliation(s)
- Phivos Phylactou
- Department of Rehabilitation Sciences, Faculty of Health Sciences, Cyprus University of Technology, Limassol 3041, Cyprus
| | - Andria Shimi
- Department of Psychology, Faculty of Social Sciences and Education, University of Cyprus, CY-1678 Nicosia, Cyprus
| | - Nikos Konstantinou
- Department of Rehabilitation Sciences, Faculty of Health Sciences, Cyprus University of Technology, Limassol 3041, Cyprus
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8
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Adam KCS, Rademaker RL, Serences JT. Dynamics Are the Only Constant in Working Memory. J Cogn Neurosci 2023; 35:24-26. [PMID: 36322835 PMCID: PMC9722602 DOI: 10.1162/jocn_a_01941] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
In this short perspective, we reflect upon our tendency to use oversimplified and idiosyncratic tasks in a quest to discover general mechanisms of working memory. We discuss how the work of Mark Stokes and collaborators has looked beyond localized, temporally persistent neural activity and shifted focus toward the importance of distributed, dynamic neural codes for working memory. A critical lesson from this work is that using simplified tasks does not automatically simplify the neural computations supporting behavior (even if we wish it were so). Moreover, Stokes' insights about multidimensional dynamics highlight the flexibility of the neural codes underlying cognition and have pushed the field to look beyond static measures of working memory.
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Affiliation(s)
| | - Rosanne L. Rademaker
- Ernst Strüngmann Institute for Neuroscience in cooperation with the Max Planck Society, Frankfurt, Germany
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9
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Chota S, Leto C, van Zantwijk L, Van der Stigchel S. Attention rhythmically samples multi-feature objects in working memory. Sci Rep 2022; 12:14703. [PMID: 36038570 PMCID: PMC9424255 DOI: 10.1038/s41598-022-18819-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/19/2022] [Indexed: 11/14/2022] Open
Abstract
Attention allows us to selectively enhance processing of specific locations or features in our external environment while filtering out irrelevant information. It is currently hypothesized that this is achieved through boosting of relevant sensory signals which biases the competition between neural representations. Recent neurophysiological and behavioral studies revealed that attention is a fundamentally rhythmic process, tightly linked to neural oscillations in frontoparietal networks. Instead of continuously highlighting a single object or location, attention rhythmically alternates between multiple relevant representations at a frequency of 3–8 Hz. However, attention cannot only be directed towards the external world but also towards internal visual working memory (VWM) representations, e.g. when selecting one of several search templates to find corresponding objects in the external world. Two recent studies demonstrate that single-feature objects in VWM are attended in a similar rhythmic fashion as perceived objects. Here we add to the literature by showing that non-spatial retro-cues initiate comparable theta-rhythmic sampling of multi-feature objects in VWM. Our findings add to the converging body of evidence that external and internal visual representations are accessed by similar rhythmic attentional mechanisms and present a potential solution to the binding problem in working memory.
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Affiliation(s)
- Samson Chota
- Helmholtz Institute, Utrecht University, 3584 CS, Utrecht, The Netherlands.
| | - Carlo Leto
- Helmholtz Institute, Utrecht University, 3584 CS, Utrecht, The Netherlands
| | - Laura van Zantwijk
- Helmholtz Institute, Utrecht University, 3584 CS, Utrecht, The Netherlands
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10
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Sensory recruitment in visual short-term memory: A systematic review and meta-analysis of sensory visual cortex interference using transcranial magnetic stimulation. Psychon Bull Rev 2022; 29:1594-1624. [PMID: 35606595 DOI: 10.3758/s13423-022-02107-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/13/2022] [Indexed: 11/08/2022]
Abstract
Sensory visual areas are involved in encoding information in visual short-term memory (VSTM). Yet it remains unclear whether sensory visual cortex is a necessary component of the brain network for maintenance of information in VSTM. Here, we aimed to systematically review studies that have investigated the role of the sensory visual cortex in VSTM using transcranial magnetic stimulation (TMS) and to quantitatively explore these effects using meta-analyses. Fourteen studies were identified and reviewed. Eight studies provided sufficient data for meta-analysis. Two meta-analyses, one regarding the VSTM encoding phase (17 effect sizes) and one regarding the VSTM maintenance phase (15 effect sizes), two meta-regressions (32 effect sizes in each), and one exploratory meta-analysis were conducted. Our results indicate that the sensory visual cortex is similarly involved in both the encoding and maintenance VSTM phase. We suggest that some cases where evidence did not show significant TMS effects was due to low memory or perceptual task demands. Overall, these findings support the idea that sensory visual areas are part of the brain network responsible for successfully maintaining information in VSTM.
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11
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Henderson MM, Rademaker RL, Serences JT. Flexible utilization of spatial- and motor-based codes for the storage of visuo-spatial information. eLife 2022; 11:e75688. [PMID: 35522567 PMCID: PMC9075954 DOI: 10.7554/elife.75688] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 04/24/2022] [Indexed: 01/26/2023] Open
Abstract
Working memory provides flexible storage of information in service of upcoming behavioral goals. Some models propose specific fixed loci and mechanisms for the storage of visual information in working memory, such as sustained spiking in parietal and prefrontal cortex during working memory maintenance. An alternative view is that information can be remembered in a flexible format that best suits current behavioral goals. For example, remembered visual information might be stored in sensory areas for easier comparison to future sensory inputs, or might be re-coded into a more abstract action-oriented format and stored in motor areas. Here, we tested this hypothesis using a visuo-spatial working memory task where the required behavioral response was either known or unknown during the memory delay period. Using functional magnetic resonance imaging (fMRI) and multivariate decoding, we found that there was less information about remembered spatial position in early visual and parietal regions when the required response was known versus unknown. Furthermore, a representation of the planned motor action emerged in primary somatosensory, primary motor, and premotor cortex during the same task condition where spatial information was reduced in early visual cortex. These results suggest that the neural networks supporting working memory can be strategically reconfigured depending on specific behavioral requirements during a canonical visual working memory paradigm.
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Affiliation(s)
- Margaret M Henderson
- Neurosciences Graduate Program, University of California, San DiegoSan DiegoUnited States
- Department of Machine Learning, Carnegie Mellon UniversityPittsburghUnited States
- Neuroscience Institute, Carnegie Mellon UniversityPittsburghUnited States
| | - Rosanne L Rademaker
- Department of Psychology, University of California, San DiegoSan DiegoUnited States
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck SocietyFrankfurtGermany
| | - John T Serences
- Neurosciences Graduate Program, University of California, San DiegoSan DiegoUnited States
- Department of Psychology, University of California, San DiegoSan DiegoUnited States
- Kavli Foundation for the Brain and Mind, University of California, San DiegoSan DiegoUnited States
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12
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Kosilo M, Martinovic J, Haenschel C. Luminance Contrast Drives Interactions between Perception and Working Memory. J Cogn Neurosci 2022; 34:1128-1147. [PMID: 35468214 DOI: 10.1162/jocn_a_01852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Visual working memory (WM) enables the use of past sensory experience in guiding behavior. Yet, laboratory tasks commonly evaluate WM in a way that separates it from its sensory bottleneck. To understand how perception interacts with visual memory, we used a delayed shape recognition task to probe how WM may differ for stimuli that bias processing toward different visual pathways. Luminance compared with chromatic signals are more efficient in driving the processing of shapes and may thus also lead to better WM encoding, maintenance, and memory recognition. To evaluate this prediction, we conducted two experiments. In the first psychophysical experiment, we measured contrast thresholds for different WM loads. Luminance contrast was encoded into WM more efficiently than chromatic contrast, even when both sets of stimuli were equated for discriminability. In the second experiment, which also equated stimuli for discriminability, early sensory responses in the EEG that are specific to luminance pathways were modulated by WM load and thus likely reflect the neural substrate of the increased efficiency. Our results cannot be accounted for by simple saliency differences between luminance and color. Rather, they provide evidence for a direct connection between low-level perceptual mechanisms and WM by showing a crucial role of luminance for forming WM representations of shape.
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Affiliation(s)
- Maciej Kosilo
- University of London, United Kingdom.,University of Lisbon, Portugal
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13
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Yoo AH, Bolaños A, Hallenbeck GE, Rahmati M, Sprague TC, Curtis CE. Behavioral Prioritization Enhances Working Memory Precision and Neural Population Gain. J Cogn Neurosci 2021; 34:365-379. [PMID: 34942647 DOI: 10.1162/jocn_a_01804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Humans allocate visual working memory (WM) resource according to behavioral relevance, resulting in more precise memories for more important items. Theoretically, items may be maintained by feature-tuned neural populations, where the relative gain of the populations encoding each item determines precision. To test this hypothesis, we compared the amplitudes of delay period activity in the different parts of retinotopic maps representing each of several WM items, predicting the amplitudes would track behavioral priority. Using fMRI, we scanned participants while they remembered the location of multiple items over a WM delay and then reported the location of one probed item using a memory-guided saccade. Importantly, items were not equally probable to be probed (0.6, 0.3, 0.1, 0.0), which was indicated with a precue. We analyzed fMRI activity in 10 visual field maps in occipital, parietal, and frontal cortex known to be important for visual WM. In early visual cortex, but not association cortex, the amplitude of BOLD activation within voxels corresponding to the retinotopic location of visual WM items increased with the priority of the item. Interestingly, these results were contrasted with a common finding that higher-level brain regions had greater delay period activity, demonstrating a dissociation between the absolute amount of activity in a brain area and the activity of different spatially selective populations within it. These results suggest that the distribution of WM resources according to priority sculpts the relative gains of neural populations that encode items, offering a neural mechanism for how prioritization impacts memory precision.
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14
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Hallenbeck GE, Sprague TC, Rahmati M, Sreenivasan KK, Curtis CE. Working memory representations in visual cortex mediate distraction effects. Nat Commun 2021; 12:4714. [PMID: 34354071 PMCID: PMC8342709 DOI: 10.1038/s41467-021-24973-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 07/13/2021] [Indexed: 11/17/2022] Open
Abstract
Although the contents of working memory can be decoded from visual cortex activity, these representations may play a limited role if they are not robust to distraction. We used model-based fMRI to estimate the impact of distracting visual tasks on working memory representations in several visual field maps in visual and frontoparietal association cortex. Here, we show distraction causes the fidelity of working memory representations to briefly dip when both the memorandum and distractor are jointly encoded by the population activities. Distraction induces small biases in memory errors which can be predicted by biases in neural decoding in early visual cortex, but not other regions. Although distraction briefly disrupts working memory representations, the widespread redundancy with which working memory information is encoded may protect against catastrophic loss. In early visual cortex, the neural representation of information in working memory and behavioral performance are intertwined, solidifying its importance in visual memory. The relative roles of visual, parietal, and frontal cortex in working memory have been actively debated. Here, the authors show that distraction impacts visual working memory representations in primary visual areas, indicating that these regions play a key role in the maintenance of working memory.
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Affiliation(s)
| | - Thomas C Sprague
- Department of Psychology, New York University, New York, NY, USA.,Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA, USA
| | - Masih Rahmati
- Department of Psychology, New York University, New York, NY, USA.,Center for Neural Science, New York University, New York, NY, USA
| | - Kartik K Sreenivasan
- Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, UAE
| | - Clayton E Curtis
- Department of Psychology, New York University, New York, NY, USA. .,Center for Neural Science, New York University, New York, NY, USA.
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Curtis CE, Sprague TC. Persistent Activity During Working Memory From Front to Back. Front Neural Circuits 2021; 15:696060. [PMID: 34366794 PMCID: PMC8334735 DOI: 10.3389/fncir.2021.696060] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/28/2021] [Indexed: 01/06/2023] Open
Abstract
Working memory (WM) extends the duration over which information is available for processing. Given its importance in supporting a wide-array of high level cognitive abilities, uncovering the neural mechanisms that underlie WM has been a primary goal of neuroscience research over the past century. Here, we critically review what we consider the two major "arcs" of inquiry, with a specific focus on findings that were theoretically transformative. For the first arc, we briefly review classic studies that led to the canonical WM theory that cast the prefrontal cortex (PFC) as a central player utilizing persistent activity of neurons as a mechanism for memory storage. We then consider recent challenges to the theory regarding the role of persistent neural activity. The second arc, which evolved over the last decade, stemmed from sophisticated computational neuroimaging approaches enabling researchers to decode the contents of WM from the patterns of neural activity in many parts of the brain including early visual cortex. We summarize key findings from these studies, their implications for WM theory, and finally the challenges these findings pose. Our goal in doing so is to identify barriers to developing a comprehensive theory of WM that will require a unification of these two "arcs" of research.
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Affiliation(s)
- Clayton E. Curtis
- Department of Psychology, New York University, New York, NY, United States
- Center for Neural Science, New York University, New York, NY, United States
| | - Thomas C. Sprague
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
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Xu Y. Towards a better understanding of information storage in visual working memory. VISUAL COGNITION 2021; 29:437-445. [DOI: 10.1080/13506285.2021.1946230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Yaoda Xu
- Department of Psychology, Yale University, New Haven, USA
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