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Lateral Bias in Visual Working Memory. Symmetry (Basel) 2022. [DOI: 10.3390/sym14122509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The present study aimed to evaluate functional cerebral asymmetries of visual working memory (VWM) in relation to language lateralization. The bilateral change detection paradigm with capital letters as stimuli and the translingual lexical decision task were used to assess VWM and language asymmetry, respectively, in a sample of 99 younger healthy participants (59 women). Participant attention was cued towards right or left visual half-field. For the VWM task, men and women were more accurate and faster when stimuli were presented in the right visual half-field compared to the left visual half-field. As expected, a significant right visual half-field advantage was demonstrated in the lexical decision task in performance accuracy (but not response time). The results also revealed no relationship between lateralization in VWM and lexical decision. VWM performance accuracy decreased significantly with increasing asymmetry. This relationship was significant for women, but not men. Taken together, the present study demonstrates that the lateral bias in visual working memory is independent from language lateralization, and less lateralized individuals perform better than individuals with larger asymmetries in both visual half-field tasks.
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2
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Boran E, Hilfiker P, Stieglitz L, Sarnthein J, Klaver P. Persistent neuronal firing in the medial temporal lobe supports performance and workload of visual working memory in humans. Neuroimage 2022; 254:119123. [PMID: 35321857 DOI: 10.1016/j.neuroimage.2022.119123] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 03/18/2022] [Accepted: 03/19/2022] [Indexed: 11/25/2022] Open
Abstract
The involvement of the medial temporal lobe (MTL) in working memory is controversially discussed. Recent findings suggest that persistent neural firing in the hippocampus during maintenance in verbal working memory is associated with workload. Here, we recorded single neuron firing in 13 epilepsy patients (7 male) while they performed a visual working memory task. The number of coloured squares in the stimulus set determined the workload of the trial. Performance was almost perfect for low workload (1 and 2 squares) and dropped at high workload (4 and 6 squares), suggesting that high workload exceeded working memory capacity. We identified maintenance neurons in MTL neurons that showed persistent firing during the maintenance period. More maintenance neurons were found in the hippocampus for trials with correct compared to incorrect performance. Maintenance neurons increased and decreased firing in the hippocampus and increased firing in the entorhinal cortex for high compared to low workload. Population firing predicted workload particularly during the maintenance period. Prediction accuracy of workload based on single-trial activity during maintenance was strongest for neurons in the entorhinal cortex and hippocampus. The data suggest that persistent neural firing in the MTL reflects a domain-general process of maintenance supporting performance and workload of multiple items in working memory below and beyond working memory capacity. Persistent neural firing during maintenance in the entorhinal cortex may be associated with its preference to process visual-spatial arrays.
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Affiliation(s)
- Ece Boran
- Department of Neurosurgery, University Hospital Zurich (USZ), University of Zurich, 8091 Zurich, Switzerland
| | | | - Lennart Stieglitz
- Department of Neurosurgery, University Hospital Zurich (USZ), University of Zurich, 8091 Zurich, Switzerland
| | - Johannes Sarnthein
- Department of Neurosurgery, University Hospital Zurich (USZ), University of Zurich, 8091 Zurich, Switzerland; Neuroscience Center Zurich, ETH Zurich, 8057 Zurich, Switzerland.
| | - Peter Klaver
- University of Teacher Education in Special Needs, 8050 Zurich, Switzerland; Institute of Psychology, University of Zurich, 8050 Zurich, Switzerland; School of Psychology, University of Surrey, GU2 7XH Guildford, UK.
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Román-López TV, Caballero-Sánchez U, Cisneros-Luna S, Franco-Rodríguez JA, Méndez-Díaz M, Prospéro-García O, Ruiz-Contreras AE. Brain electrical activity from encoding to retrieval while maintaining and manipulating information in working memory. Memory 2019; 27:1063-1078. [DOI: 10.1080/09658211.2019.1620287] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Talía V. Román-López
- Lab. Neurogenómica Cognitiva, Coord. Psicobiología y Neurociencias, Fac. Psicología, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | - Ulises Caballero-Sánchez
- Lab. Neurogenómica Cognitiva, Coord. Psicobiología y Neurociencias, Fac. Psicología, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | - Silvia Cisneros-Luna
- Lab. Neurogenómica Cognitiva, Coord. Psicobiología y Neurociencias, Fac. Psicología, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | - J. Antonio Franco-Rodríguez
- Lab. Neurogenómica Cognitiva, Coord. Psicobiología y Neurociencias, Fac. Psicología, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | - Mónica Méndez-Díaz
- Lab. Cannabinoides, Depto. Fisiología, Fac. Medicina, UNAM, Ciudad de México, México
| | - Oscar Prospéro-García
- Lab. Cannabinoides, Depto. Fisiología, Fac. Medicina, UNAM, Ciudad de México, México
| | - Alejandra E. Ruiz-Contreras
- Lab. Neurogenómica Cognitiva, Coord. Psicobiología y Neurociencias, Fac. Psicología, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
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4
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Gu C, Liu ZX, Tannock R, Woltering S. Neural processing of working memory in adults with ADHD in a visuospatial change detection task with distractors. PeerJ 2018; 6:e5601. [PMID: 30245935 PMCID: PMC6149497 DOI: 10.7717/peerj.5601] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 08/15/2018] [Indexed: 11/20/2022] Open
Abstract
Individuals with Attention-Deficit Hyperactivity Disorder (ADHD) are often characterized by deficits in working memory (WM), which manifest in academic, professional, and mental health difficulties. To better understand the underlying mechanisms of these presumed WM deficits, we compared adults with ADHD to their peers on behavioral and neural indices of WM. We used a visuospatial change detection task with distractors which was designed to assess the brain’s ability to effectively filter out distractors from WM, in addition to testing for effects of WM load. Twenty-seven unmedicated adults with ADHD were compared to 27 matched peers on event-related potential (ERP) measures of WM, i.e., the contralateral delay activity (CDA). Despite severe impairments in everyday life functioning, findings showed no difference in deficits in behavioral tests of working memory for adults with ADHD compared to their peers. Interestingly, there were differences in neural activity between individuals with ADHD and their peers showing that the CDA of individuals with ADHD did not distinguish between high, distractor, and low memory load conditions. These data suggest, in the face of comparable behavioral performance, a difference in neural processing efficiency, wherein the brains of individuals with ADHD may not be as selective in the allocation of neural resources to perform a WM task.
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Affiliation(s)
- Chao Gu
- Department of Educational Psychology, Texas A&M University, College Station, TX, United States of America
| | - Zhong-Xu Liu
- Department of Applied Psychology and Human Development, University of Toronto, Toronto, Canada.,Rotman Research Institute of Baycrest Centre, Toronto, Canada
| | - Rosemary Tannock
- Department of Applied Psychology and Human Development, University of Toronto, Toronto, Canada.,Neuroscience and Mental Health Research Program, Sickkids Hospital, Toronto, Canada
| | - Steven Woltering
- Department of Educational Psychology, Texas A&M University, College Station, TX, United States of America.,Department of Applied Psychology and Human Development, University of Toronto, Toronto, Canada
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5
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Contralateral delay activity does not reflect behavioral feature load in visual working memory. Biol Psychol 2018; 137:107-115. [PMID: 30055237 DOI: 10.1016/j.biopsycho.2018.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 07/11/2018] [Accepted: 07/12/2018] [Indexed: 11/23/2022]
Abstract
An ongoing debate in visual working memory research is concentrated on whether visual working memory capacity is determined solely by the number of objects to be memorized, or additionally by the number of relevant features contained within objects. Using a novel change detection task that contained multi-feature objects we examined the effect of both object number and feature number on visual working memory capacity, change detection sensitivity, and posterior slow wave event-related brain potential (ERP) activity. Behaviorally, working memory capacity and sensitivity were modulated as a function of both the number of objects and the number of features memorized per object. However, the Contralateral Delay Activity (CDA) was only sensitive to the number of objects, but not to the number of features. This suggests that while both objects and features contribute to limitations in visual working memory capacity, the CDA is an insufficient mechanism to account for feature level representations.
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Figueira JSB, Oliveira L, Pereira MG, Pacheco LB, Lobo I, Motta-Ribeiro GC, David IA. An unpleasant emotional state reduces working memory capacity: electrophysiological evidence. Soc Cogn Affect Neurosci 2018; 12:984-992. [PMID: 28402534 PMCID: PMC5472131 DOI: 10.1093/scan/nsx030] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 03/01/2017] [Indexed: 01/20/2023] Open
Abstract
Emotional states can guide the actions and decisions we make in our everyday life through their influence on cognitive processes such as working memory (WM). We investigated the long-lasting interference that an unpleasant emotional state had on goal-relevant WM representations from an electrophysiological perspective. Participants performed a change detection task that was preceded by the presentation of unpleasant or neutral task-irrelevant pictures in a blocked fashion. We focused on the contralateral delay activity (CDA), an event-related potential that is sensitive to the number of task-relevant items stored in WM. We found that the asymptotic limit for the CDA amplitude was lower during the unpleasant emotional state than during the neutral one; that is, an emotional state was capable of reducing how many task-relevant items the participants could hold in WM. Furthermore, both the individuals who experienced more intrusive thoughts and those who were dispositionally anxious were more susceptible to the influence of the emotional state. We provide evidence that an unpleasant emotional state diminished visual WM for task-relevant items, particularly in susceptible individuals. These results open new avenues to uncover the emotional-cognitive processing that underlies maladaptive WM representations and the role of such processing in the development of mental illness.
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Affiliation(s)
- Jessica S B Figueira
- Laboratório de Neurofisiologia do Comportamento, Departamento de Fisiologia e Farmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Leticia Oliveira
- Laboratório de Neurofisiologia do Comportamento, Departamento de Fisiologia e Farmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Mirtes G Pereira
- Laboratório de Neurofisiologia do Comportamento, Departamento de Fisiologia e Farmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Luiza B Pacheco
- Laboratório de Neurofisiologia do Comportamento, Departamento de Fisiologia e Farmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Isabela Lobo
- Laboratório de Neurofisiologia do Comportamento, Departamento de Fisiologia e Farmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil.,MograbiLab, Departamento de Psicologia, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gabriel C Motta-Ribeiro
- Laboratório de Engenharia Pulmonar, Programa de Engenharia Biomédica, COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Isabel A David
- Laboratório de Neurofisiologia do Comportamento, Departamento de Fisiologia e Farmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
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7
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Ahmad RF, Malik AS, Kamel N, Reza F, Abdullah JM. Simultaneous EEG-fMRI for working memory of the human brain. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2016; 39:363-78. [PMID: 27043850 DOI: 10.1007/s13246-016-0438-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 03/14/2016] [Indexed: 02/06/2023]
Abstract
Memory plays an important role in human life. Memory can be divided into two categories, i.e., long term memory and short term memory (STM). STM or working memory (WM) stores information for a short span of time and it is used for information manipulations and fast response activities. WM is generally involved in the higher cognitive functions of the brain. Different studies have been carried out by researchers to understand the WM process. Most of these studies were based on neuroimaging modalities like fMRI, EEG, MEG etc., which use standalone processes. Each neuroimaging modality has some pros and cons. For example, EEG gives high temporal resolution but poor spatial resolution. On the other hand, the fMRI results have a high spatial resolution but poor temporal resolution. For a more in depth understanding and insight of what is happening inside the human brain during the WM process or during cognitive tasks, high spatial as well as high temporal resolution is desirable. Over the past decade, researchers have been working to combine different modalities to achieve a high spatial and temporal resolution at the same time. Developments of MRI compatible EEG equipment in recent times have enabled researchers to combine EEG-fMRI successfully. The research publications in simultaneous EEG-fMRI have been increasing tremendously. This review is focused on the WM research involving simultaneous EEG-fMRI data acquisition and analysis. We have covered the simultaneous EEG-fMRI application in WM and data processing. Also, it adds to potential fusion methods which can be used for simultaneous EEG-fMRI for WM and cognitive tasks.
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Affiliation(s)
- Rana Fayyaz Ahmad
- Centre for Intelligent Signal and Imaging Research (CISIR), Tronoh, Malaysia. .,Department of Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak, Malaysia.
| | - Aamir Saeed Malik
- Centre for Intelligent Signal and Imaging Research (CISIR), Tronoh, Malaysia. .,Department of Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak, Malaysia.
| | - Nidal Kamel
- Centre for Intelligent Signal and Imaging Research (CISIR), Tronoh, Malaysia.,Department of Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, 32610, Bandar Seri Iskandar, Perak, Malaysia
| | - Faruque Reza
- Department of Neurosciences, Universiti Sains Malaysia, Kubang Kerian, 16150, Kota Bharu, Kelantan, Malaysia.,Centre for Neuroscience Services and Research, Universiti Sains Malaysia, Kubang Kerian, 16150, Kota Bharu, Kelantan, Malaysia
| | - Jafri Malin Abdullah
- Department of Neurosciences, Universiti Sains Malaysia, Kubang Kerian, 16150, Kota Bharu, Kelantan, Malaysia.,Centre for Neuroscience Services and Research, Universiti Sains Malaysia, Kubang Kerian, 16150, Kota Bharu, Kelantan, Malaysia
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8
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Luria R, Balaban H, Awh E, Vogel EK. The contralateral delay activity as a neural measure of visual working memory. Neurosci Biobehav Rev 2016; 62:100-8. [PMID: 26802451 DOI: 10.1016/j.neubiorev.2016.01.003] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 09/10/2015] [Accepted: 01/11/2016] [Indexed: 12/14/2022]
Abstract
The contralateral delay activity (CDA) is a negative slow wave sensitive to the number of objects maintained in visual working memory (VWM). In recent years, a growing number of labs started to use the CDA in order to investigate VWM, leading to many fascinating discoveries. Here, we discuss the recent developments and contribution of the CDA in various research fields. Importantly, we report two meta-analyses that unequivocally validate the relationship between the set-size increase in the CDA amplitude and the individual VWM capacity, and between the CDA and filtering efficiency. We further discuss how the CDA was used to study the role of VWM in visual search, multiple object tracking, grouping, binding, and whether VWM capacity allocation is determined by the items' resolution or instead by the number of objects regardless of their complexity. In addition, we report how the CDA has been used to characterize specific VWM deficits in special populations.
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Affiliation(s)
- Roy Luria
- The School of Psychological Sciences, Tel Aviv University, 6997801, Israel; The Sagol School of Neuroscience, Tel Aviv University, 6997801, Israel.
| | - Halely Balaban
- The School of Psychological Sciences, Tel Aviv University, 6997801, Israel; The Sagol School of Neuroscience, Tel Aviv University, 6997801, Israel
| | - Edward Awh
- Department of Psychology, University of Chicago, IL 60637, United States
| | - Edward K Vogel
- Department of Psychology, University of Chicago, IL 60637, United States
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9
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Thelen A, Talsma D, Murray MM. Single-trial multisensory memories affect later auditory and visual object discrimination. Cognition 2015; 138:148-60. [DOI: 10.1016/j.cognition.2015.02.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 11/12/2014] [Accepted: 02/09/2015] [Indexed: 11/30/2022]
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10
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Quak M, London RE, Talsma D. A multisensory perspective of working memory. Front Hum Neurosci 2015; 9:197. [PMID: 25954176 PMCID: PMC4404829 DOI: 10.3389/fnhum.2015.00197] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/25/2015] [Indexed: 11/29/2022] Open
Abstract
Although our sensory experience is mostly multisensory in nature, research on working memory representations has focused mainly on examining the senses in isolation. Results from the multisensory processing literature make it clear that the senses interact on a more intimate manner than previously assumed. These interactions raise questions regarding the manner in which multisensory information is maintained in working memory. We discuss the current status of research on multisensory processing and the implications of these findings on our theoretical understanding of working memory. To do so, we focus on reviewing working memory research conducted from a multisensory perspective, and discuss the relation between working memory, attention, and multisensory processing in the context of the predictive coding framework. We argue that a multisensory approach to the study of working memory is indispensable to achieve a realistic understanding of how working memory processes maintain and manipulate information.
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Affiliation(s)
- Michel Quak
- Department of Experimental Psychology, Ghent University Ghent, Belgium
| | | | - Durk Talsma
- Department of Experimental Psychology, Ghent University Ghent, Belgium
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11
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The reliability and internal consistency of one-shot and flicker change detection for measuring individual differences in visual working memory capacity. Mem Cognit 2014; 43:397-420. [DOI: 10.3758/s13421-014-0492-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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The functional profile of the human amygdala in affective processing: Insights from intracranial recordings. Cortex 2014; 60:10-33. [DOI: 10.1016/j.cortex.2014.06.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 01/30/2014] [Accepted: 06/04/2014] [Indexed: 11/21/2022]
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Ye C, Zhang L, Liu T, Li H, Liu Q. Visual working memory capacity for color is independent of representation resolution. PLoS One 2014; 9:e91681. [PMID: 24618685 PMCID: PMC3950244 DOI: 10.1371/journal.pone.0091681] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 02/14/2014] [Indexed: 11/18/2022] Open
Abstract
Background The relationship between visual working memory (VWM) capacity and resolution of representation have been extensively investigated. Several recent ERP studies using orientation (or arrow) stimuli suggest that there is an inverse relationship between VWM capacity and representation resolution. However, different results have been obtained in studies using color stimuli. This could be due to important differences in the experimental paradigms used in previous studies. Methodology/Principal Findings We examined whether the same relationship between capacity and resolution holds for color information. Participants performed a color change detection task while their electroencephalography was recorded. We manipulated representation resolution by asking participants to detect either a salient change (low-resolution) or a subtle change (high-resolution) in color. We used an ERP component known as contralateral delay activity (CDA) to index the amount of information maintained in VWM. The result demonstrated the same pattern for both low- and high-resolution conditions, with no difference between conditions. Conclusions/Significance This result suggests that VWM always represents a fixed number of approximately 3–4 colors regardless of the resolution of representation.
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Affiliation(s)
- Chaoxiong Ye
- Department of Educational Science and Technology, Minnan Normal University, Zhangzhou, China
| | - Lingcong Zhang
- Department of Educational Science and Technology, Minnan Normal University, Zhangzhou, China
| | - Taosheng Liu
- Department of Psychology and Neuroscience Program, Michigan State University, East Lansing, Michigan, United States of America
| | - Hong Li
- School of Psychology, Liaoning Normal University, Dalian, China
| | - Qiang Liu
- School of Psychology, Liaoning Normal University, Dalian, China
- * E-mail:
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Klaver P, Talsma D. Behind the scenes: How visual memory load biases selective attention during processing of visual streams. Psychophysiology 2013; 50:1133-46. [DOI: 10.1111/psyp.12126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 06/02/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Peter Klaver
- Institute of Psychology; University of Zurich; Zurich Switzerland
| | - Durk Talsma
- Department of Experimental Psychology; Ghent University; Ghent Belgium
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15
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von Allmen DY, Wurmitzer K, Martin E, Klaver P. Neural activity in the hippocampus predicts individual visual short-term memory capacity. Hippocampus 2013; 23:606-15. [DOI: 10.1002/hipo.22121] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2013] [Indexed: 11/09/2022]
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16
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Gao Z, Ding X, Yang T, Liang J, Shui R. Coarse-to-fine construction for high-resolution representation in visual working memory. PLoS One 2013; 8:e57913. [PMID: 23469103 PMCID: PMC3585254 DOI: 10.1371/journal.pone.0057913] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Accepted: 01/28/2013] [Indexed: 11/19/2022] Open
Abstract
Background This study explored whether the high-resolution representations created by visual working memory (VWM) are constructed in a coarse-to-fine or all-or-none manner. The coarse-to-fine hypothesis suggests that coarse information precedes detailed information in entering VWM and that its resolution increases along with the processing time of the memory array, whereas the all-or-none hypothesis claims that either both enter into VWM simultaneously, or neither does. Methodology/Principal Findings We tested the two hypotheses by asking participants to remember two or four complex objects. An ERP component, contralateral delay activity (CDA), was used as the neural marker. CDA is higher for four objects than for two objects when coarse information is primarily extracted; yet, this CDA difference vanishes when detailed information is encoded. Experiment 1 manipulated the comparison difficulty of the task under a 500-ms exposure time to determine a condition in which the detailed information was maintained. No CDA difference was found between two and four objects, even in an easy-comparison condition. Thus, Experiment 2 manipulated the memory array’s exposure time under the easy-comparison condition and found a significant CDA difference at 100 ms while replicating Experiment 1′s results at 500 ms. In Experiment 3, the 500-ms memory array was blurred to block the detailed information; this manipulation reestablished a significant CDA difference. Conclusions/Significance These findings suggest that the creation of high-resolution representations in VWM is a coarse-to-fine process.
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Affiliation(s)
- Zaifeng Gao
- Department of Psychology and Behavioral Sciences, Zhejiang University, Hangzhou, China
| | - Xiaowei Ding
- Department of Psychology and Behavioral Sciences, Zhejiang University, Hangzhou, China
| | - Tong Yang
- Department of Psychology and Behavioral Sciences, Zhejiang University, Hangzhou, China
| | - Junying Liang
- Department of Psychology and Behavioral Sciences, Zhejiang University, Hangzhou, China
| | - Rende Shui
- Department of Psychology and Behavioral Sciences, Zhejiang University, Hangzhou, China
- * E-mail:
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17
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Shen M, Yu W, Xu X, Gao Z. Building blocks of visual working memory: objects or Boolean maps? J Cogn Neurosci 2012; 25:743-53. [PMID: 23249354 DOI: 10.1162/jocn_a_00348] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The nature of the building blocks of information in visual working memory (VWM) is a fundamental issue that has not been well resolved. Most researchers take objects as the building blocks, although this perspective has received criticism. The objects could be physically separated ones (strict object hypothesis) or hierarchical objects created from separated individuals (broad object hypothesis). Meanwhile, a newly proposed Boolean map theory for visual attention suggests that Boolean maps may be the building blocks of VWM (Boolean map hypothesis); this perspective could explain many critical findings of VWM. However, no previous study has examined these hypotheses. We explored this issue by focusing on a critical point on which they make distinct predictions. We asked participants to remember two distinct objects (2-object), three distinct objects (3-object), or three objects with repeated information (mixed-3-object, e.g., one red bar and two green bars, green bars could be represented as one hierarchical object) and adopted contralateral delay activity (CDA) to tap into the maintenance phase of VWM. The mixed-3-object condition could generate two Boolean maps, three objects, or three objects most of the time (hierarchical objects are created in certain trials, retaining two objects). Simple orientations (Experiment 1) and colors (Experiments 2 and 3) were used as stimuli. Although the CDA of the mixed-3-object condition was slightly lower than that of the 3-object condition, no significant difference was revealed between them. Both conditions displayed significantly higher CDAs than the 2-object condition. These findings support the broad object hypothesis. We further suggest that Boolean maps might be the unit for retrieval/comparison in VWM.
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Affiliation(s)
- Mowei Shen
- Zhejiang University, Hang Zhou, P R China
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18
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Gao Z, Xu X, Chen Z, Yin J, Shen M, Shui R. Contralateral delay activity tracks object identity information in visual short term memory. Brain Res 2011; 1406:30-42. [PMID: 21757188 DOI: 10.1016/j.brainres.2011.06.049] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 06/10/2011] [Accepted: 06/21/2011] [Indexed: 11/27/2022]
Abstract
Previous studies suggested that ERP component contralateral delay activity (CDA) tracks the number of objects containing identity information stored in visual short term memory (VSTM). Later MEG and fMRI studies implied that its neural source lays in superior IPS. However, since the memorized stimuli in previous studies were displayed in distinct spatial locations, hence possibly CDA tracks the object-location information instead. Moreover, a recent study implied the activation in superior IPS reflected the location load. The current research thus explored whether CDA tracks the object-location load or the object-identity load, and its neural sources. Participants were asked to remember one color, four identical colors or four distinct colors. The four-identical-color condition was the critical one because it contains the same amount of identity information as that of one color while the same amount of location information as that of four distinct colors. To ensure the participants indeed selected four colors in the four-identical-color condition, we also split the participants into two groups (low- vs. high-capacity), analyzed late positive component (LPC) in the prefrontal area, and collected participant's subjective-report. Our results revealed that most of the participants selected four identical colors. Moreover, regardless of capacity-group, there was no difference on CDA between one color and four identical colors yet both were lower than 4 distinct colors. Besides, the source of CDA was located in the superior parietal lobule, which is very close to the superior IPS. These results support the statement that CDA tracks the object identity information in VSTM.
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Affiliation(s)
- Zaifeng Gao
- Department of Psychology and Behavioral Sciences, Zhejiang University, PR China
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