1
|
Oblak A, Dragan O, Slana Ozimič A, Kordeš U, Purg N, Bon J, Repovš G. What is it like to do a visuo-spatial working memory task: A qualitative phenomenological study of the visual span task. Conscious Cogn 2024; 118:103628. [PMID: 38232628 DOI: 10.1016/j.concog.2023.103628] [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: 02/01/2023] [Revised: 09/12/2023] [Accepted: 12/15/2023] [Indexed: 01/19/2024]
Abstract
Working memory is typically measured with specifically designed psychological tasks. When evaluating the validity of working memory tasks, we commonly focus on the reliability of the outcome measurements. Only rarely do we focus on how participants experience these tasks. Accounting for lived experience of working memory task may help us better understand variability in working memory performance and conscious experience in general. We replicated recently established protocols for the phenomenological investigation of working memory using the visual span task. We collected subjective reports from eighteen healthy participants (10 women) aged 21 to 35 years. We observed that working memory can be phenomenologically characterized at three different time scales: background feelings, strategies, and tactics. On the level of tactics, we identified transmodality (i.e., how one modality of lived experience can be transformed into another one) as the central phenomenological dynamic at play during working memory task performance.
Collapse
Affiliation(s)
- Aleš Oblak
- Laboratory for Cognitive Neuroscience and Psychopathology, University Psychiatric Clinic Ljubljana, Ljubljana, Slovenia.
| | - Oskar Dragan
- Middle European Interdisciplinary Master's Program in Cognitive Science, Austria
| | - Anka Slana Ozimič
- Department of Psychology, University of Ljubljana, Ljubljana, Slovenia
| | - Urban Kordeš
- Center for Cognitive Science, Faculty of Education, University of Ljubljana, Ljubljana, Slovenia
| | - Nina Purg
- Department of Psychology, University of Ljubljana, Ljubljana, Slovenia
| | - Jurij Bon
- Laboratory for Cognitive Neuroscience and Psychopathology, University Psychiatric Clinic Ljubljana, Ljubljana, Slovenia; Department of Psychiatry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Grega Repovš
- Department of Psychology, University of Ljubljana, Ljubljana, Slovenia
| |
Collapse
|
2
|
MacLean MW, Hadid V, Spreng RN, Lepore F. Revealing robust neural correlates of conscious and unconscious visual processing: activation likelihood estimation meta-analyses. Neuroimage 2023; 273:120088. [PMID: 37030413 DOI: 10.1016/j.neuroimage.2023.120088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 04/09/2023] Open
Abstract
Our ability to consciously perceive information from the visual scene relies on a myriad of intrinsic neural mechanisms. Functional neuroimaging studies have sought to identify the neural correlates of conscious visual processing and to further dissociate from those pertaining to preconscious and unconscious visual processing. However, delineating what core brain regions are involved in eliciting a conscious percept remains a challenge, particularly regarding the role of prefrontal-parietal regions. We performed a systematic search of the literature that yielded a total of 54 functional neuroimaging studies. We conducted two quantitative meta-analyses using activation likelihood estimation to identify reliable patterns of activation engaged by i. conscious (n = 45 studies, comprising 704 participants) and ii. unconscious (n = 16 studies, comprising 262 participants) visual processing during various task performances. Results of the meta-analysis specific to conscious percepts quantitatively revealed reliable activations across a constellation of regions comprising the bilateral inferior frontal junction, intraparietal sulcus, dorsal anterior cingulate, angular gyrus, temporo-occipital cortex and anterior insula. Neurosynth reverse inference revealed conscious visual processing to be intertwined with cognitive terms related to attention, cognitive control and working memory. Results of the meta-analysis on unconscious percepts revealed consistent activations in the lateral occipital complex, intraparietal sulcus and precuneus. These findings highlight the notion that conscious visual processing readily engages higher-level regions including the inferior frontal junction and unconscious processing reliably recruits posterior regions, mainly the lateral occipital complex.
Collapse
|
3
|
Abstract
The extent to which we are affected by perceptual input of which we are unaware is widely debated. By measuring neural responses to sensory stimulation, neuroscientific data could complement behavioral results with valuable evidence. Here we review neuroscientific findings of processing of high-level information, as well as interactions with attention and memory. Although the results are mixed, we find initial support for processing object categories and words, possibly to the semantic level, as well as emotional expressions. Robust neural evidence for face individuation and integration of sentences or scenes is lacking. Attention affects the processing of stimuli that are not consciously perceived, and such stimuli may exogenously but not endogenously capture attention when relevant, and be maintained in memory over time. Sources of inconsistency in the literature include variability in control for awareness as well as individual differences, calling for future studies that adopt stricter measures of awareness and probe multiple processes within subjects.
Collapse
Affiliation(s)
- Liad Mudrik
- School of Psychological Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel;
| | - Leon Y Deouell
- Department of Psychology and The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel;
| |
Collapse
|
4
|
Oblak A, Slana Ozimič A, Repovš G, Kordeš U. What Individuals Experience During Visuo-Spatial Working Memory Task Performance: An Exploratory Phenomenological Study. Front Psychol 2022; 13:811712. [PMID: 35664146 PMCID: PMC9159378 DOI: 10.3389/fpsyg.2022.811712] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/30/2022] [Indexed: 11/13/2022] Open
Abstract
In experimental cognitive psychology, objects of inquiry are typically operationalized with psychological tasks. When interpreting results from such tasks, we focus primarily on behavioral measures such as reaction times and accuracy rather than experiences - i.e., phenomenology - associated with the task, and posit that the tasks elicit the desired cognitive phenomenon. Evaluating whether the tasks indeed elicit the desired phenomenon can be facilitated by understanding the experience during task performance. In this paper we explore the breadth of experiences that are elicited by and accompany task performance using in-depth phenomenological and qualitative methodology to gather subjective reports during the performance of a visuo-spatial change detection task. Thirty-one participants (18 females) were asked to remember either colors, orientations or positions of the presented stimuli and recall them after a short delay. Qualitative reports revealed rich experiential landscapes associated with the task-performance, suggesting a distinction between two broad classes of experience: phenomena at the front of consciousness and background feelings. The former includes cognitive strategies and aspects of metacognition, whereas the latter include more difficult-to-detect aspects of experience that comprise the overall sense of experience (e.g., bodily feelings, emotional atmosphere, mood). We focus primarily on the background feelings, since strategies of task-performance to a large extent map onto previously identified cognitive processes and discuss the methodological implications of our findings.
Collapse
Affiliation(s)
- Aleš Oblak
- Laboratory for Cognitive Neuroscience and Psychopathology, University Psychiatric Hospital Ljubljana, Ljubljana, Slovenia
| | - Anka Slana Ozimič
- Mind & Brain Lab, Department of Psychology, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
| | - Grega Repovš
- Mind & Brain Lab, Department of Psychology, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
| | - Urban Kordeš
- Center for Cognitive Science, Faculty of Education, University of Ljubljana, Ljubljana, Slovenia.,Observatory: Laboratory for Empirical Phenomenology, Faculty of Education, University of Ljubljana, Ljubljana, Slovenia
| |
Collapse
|
5
|
Güldener L, Jüllig A, Soto D, Pollmann S. Frontopolar Activity Carries Feature Information of Novel Stimuli During Unconscious Reweighting of Selective Attention. Cortex 2022; 153:146-165. [DOI: 10.1016/j.cortex.2022.03.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/21/2022] [Accepted: 03/29/2022] [Indexed: 11/24/2022]
|
6
|
Gambarota F, Tsuchiya N, Pastore M, Di Polito N, Sessa P. Unconscious Visual Working Memory: A critical review and Bayesian meta-analysis. Neurosci Biobehav Rev 2022; 136:104618. [PMID: 35289273 DOI: 10.1016/j.neubiorev.2022.104618] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 11/16/2022]
Abstract
The relationship between consciousness and working memory (WM) has been recently debated both at the theoretical and methodological levels (Persuh et al., 2018; Velichkovsky, 2017). While there is behavioral and neural evidence that argues for the existence of unconscious WM, several methodological concerns have been raised, rendering this issue highly controversial. To address the robustness of the previous findings, here we adopt a meta-analytic approach to estimate the effect size and heterogeneity of the previously reported unconscious WM results, also including unpublished results. We used meta-regression to isolate relevant experimental variables, in particular, consciousness manipulation and the WM paradigm to identify the source of the heterogeneity in the reported effect size of the unconscious WM. Our meta-analysis supports the existence of the unconscious WM effect and critically reveals several experimental variables that contribute to relevant heterogeneity. Our analysis clarifies several theoretical and methodological issues. We recommend that future studies explicitly operationalize the definition of consciousness, standardize the methodology and systematically explore the role of critical variables for the unconscious WM effect.
Collapse
Affiliation(s)
- Filippo Gambarota
- Department of Developmental and Social Psychology, University of Padova, Via Venezia 8, 35131, Padova, Italy; Padova Neuroscience Center, University of Padova, Via Giuseppe Orus, 2, 35131 Padova, Italy.
| | - Naotsugu Tsuchiya
- Turner Institute for Brain and Mental Health & School of Psychological Sciences, Faculty of Medicine, Nursing, and Health Sciences, Monash University, Melbourne, Victoria, Australia; Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT), Suita, Osaka 565-0871, Japan; Advanced Telecommunications Research Computational Neuroscience Laboratories, 2-2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0288, Japan.
| | - Massimiliano Pastore
- Department of Developmental and Social Psychology, University of Padova, Via Venezia 8, 35131, Padova, Italy.
| | - Nicola Di Polito
- Medical Neurosciences Program, Charité Universitätsmedizin, Charitépl 1, 10117, Berlin, Germany.
| | - Paola Sessa
- Department of Developmental and Social Psychology, University of Padova, Via Venezia 8, 35131, Padova, Italy; Padova Neuroscience Center, University of Padova, Via Giuseppe Orus, 2, 35131 Padova, Italy.
| |
Collapse
|
7
|
Sandberg K, Del Pin SH, Overgaard M, Bibby BM. A window of subliminal perception. Behav Brain Res 2022; 426:113842. [PMID: 35301023 DOI: 10.1016/j.bbr.2022.113842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 02/25/2022] [Accepted: 03/10/2022] [Indexed: 11/25/2022]
Abstract
Under labels such as unconscious processing and subliminal perception, identification of stimuli falling below the subjective threshold (whether truly unconscious or not) has been found remarkably accurate in some experiments while completely at chance in others. Here, we first identify that an apparent window of subliminal perception arises in humans under specific stimulus conditions using different experimental paradigms and analysis methods. We then show that the standard signal detection theory (SDT) model is unable to account for this window and extend it until it is. We finally compare a range of models on empirical data. The models performing best are notable for their absence of hierarchical levels, indicating that the window could be a base property of any phenomenally conscious system. The models explain previously incompatible findings in the literature, and they allow for estimations of peaks in subthreshold perception across the spectrum of stimulus saliency, which may be used in further studies of subliminal perception.
Collapse
Affiliation(s)
- Kristian Sandberg
- Center of Functionally Integrative Neuroscience, Aarhus University and Aarhus University Hospital, Universitetsbyen 3, Building 1710, 8000 Aarhus C, Denmark.
| | - Simon Hviid Del Pin
- Center of Functionally Integrative Neuroscience, Aarhus University and Aarhus University Hospital, Universitetsbyen 3, Building 1710, 8000 Aarhus C, Denmark; Consciousness Lab, Institute of Psychology, Jagiellonian University, Ingardena 6, 30-060 Krakow, Poland
| | - Morten Overgaard
- Center of Functionally Integrative Neuroscience, Aarhus University and Aarhus University Hospital, Universitetsbyen 3, Building 1710, 8000 Aarhus C, Denmark; Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B, 8000 Aarhus C, Denmark
| | - Bo Martin Bibby
- Department of Biostatistics, Aarhus University, Bartholins Allé 2, building 1261, 8000 Aarhus C, Denmark
| |
Collapse
|
8
|
Vigliecca NS. Story reading with incidental comprehension and memory: left hemisphere dominance. ARQUIVOS DE NEURO-PSIQUIATRIA 2021; 79:963-973. [PMID: 34816990 DOI: 10.1590/0004-282x-anp-2020-0489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 01/26/2021] [Indexed: 01/10/2023]
Abstract
BACKGROUND There are no studies on adults with unilateral brain lesions regarding story reading with incidental/implicit comprehension and memory, in which memory is only assessed through delayed recall. There is a need for validation of cerebral laterality in this type of verbal recall, which includes spontaneous performance (free or uncued condition (UC)), and induced-through-question performance regarding the forgotten units (cued condition (CC)). OBJECTIVES To explore the effects of unilateral brain lesions, of oral reading with expression (RE) and comprehension (RC) on delayed recall of a story, as either UC or CC; and to validate the ability of UC and CC to discriminate the side of brain injury. METHODS Data were obtained from 200 right-handed volunteers, among whom 42 had left-hemisphere injury (LHI), 49 had right-hemisphere injury (RHI) and 109 were demographically-matched healthy participants (HP). Patients who were unable to read, understand or speak were excluded. RESULTS LHI individuals presented impairment of both UC and CC, in relation to the other two groups (non-LHI) with sensitivity and specificity above 70%. LHI and RHI individuals were not significantly different in RE and RC, but they were both different from HP in all the assessments except CC, in which RHI individuals resembled HP. Despite this lack of abnormality in RHI individuals during CC, about half of this group showed impairment in UC. Additionally, whereas RE had a significant effect on UC, the moral of the story (RC) had a significant effect on both UC and CC. CONCLUSIONS The left hemisphere was dominant for this memory task involving implicit processing.
Collapse
Affiliation(s)
- Nora Silvana Vigliecca
- Consejo Nacional de Investigaciones Científicas y Técnicas de la Argentina (CONICET), Universidad Nacional de Córdoba, Instituto de Humanidades, Córdoba, Argentina.,Hospital Córdoba, Servicio de Neurología y Neurocirugía, Córdoba, Argentina
| |
Collapse
|
9
|
Delong P, Noppeney U. Semantic and spatial congruency mould audiovisual integration depending on perceptual awareness. Sci Rep 2021; 11:10832. [PMID: 34035358 PMCID: PMC8149651 DOI: 10.1038/s41598-021-90183-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 04/22/2021] [Indexed: 11/09/2022] Open
Abstract
Information integration is considered a hallmark of human consciousness. Recent research has challenged this tenet by showing multisensory interactions in the absence of awareness. This psychophysics study assessed the impact of spatial and semantic correspondences on audiovisual binding in the presence and absence of visual awareness by combining forward-backward masking with spatial ventriloquism. Observers were presented with object pictures and synchronous sounds that were spatially and/or semantically congruent or incongruent. On each trial observers located the sound, identified the picture and rated the picture's visibility. We observed a robust ventriloquist effect for subjectively visible and invisible pictures indicating that pictures that evade our perceptual awareness influence where we perceive sounds. Critically, semantic congruency enhanced these visual biases on perceived sound location only when the picture entered observers' awareness. Our results demonstrate that crossmodal influences operating from vision to audition and vice versa are interactively controlled by spatial and semantic congruency in the presence of awareness. However, when visual processing is disrupted by masking procedures audiovisual interactions no longer depend on semantic correspondences.
Collapse
Affiliation(s)
- Patrycja Delong
- Centre for Computational Neuroscience and Cognitive Robotics, University of Birmingham, Birmingham, UK.
| | - Uta Noppeney
- Centre for Computational Neuroscience and Cognitive Robotics, University of Birmingham, Birmingham, UK.,Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| |
Collapse
|
10
|
Pang DKF, Elntib S. Strongly masked content retained in memory made accessible through repetition. Sci Rep 2021; 11:10284. [PMID: 33986370 PMCID: PMC8119432 DOI: 10.1038/s41598-021-89512-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 04/21/2021] [Indexed: 02/03/2023] Open
Abstract
A growing body of evidence indicates that information can be stored even in the absence of conscious awareness. Despite these findings, unconscious memory is still poorly understood with limited evidence for unconscious iconic memory storage. Here we show that strongly masked visual data can be stored and accumulate to elicit clear perception. We used a repetition method across a wide range of conditions (Experiment 1) and a more focused follow-up experiment with enhanced masking conditions (Experiment 2). Information was stored despite being masked, demonstrating that masking did not erase or overwrite memory traces but limited perception. We examined the temporal properties and found that stored information followed a gradual but rapid decay. Extraction of meaningful information was severely impaired after 300 ms, and most data was lost after 700 ms. Our findings are congruent with theories of consciousness that are based on an integration of subliminal information and support theoretical predictions based on the global workspace theory of consciousness, especially the existence of an implicit iconic memory buffer store.
Collapse
Affiliation(s)
- Damian K. F. Pang
- grid.10025.360000 0004 1936 8470Department of Psychological Sciences, Institute of Psychology, Health and Society, University of Liverpool, Liverpool, L69 3BX UK ,grid.25879.310000 0004 1936 8972School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Stamatis Elntib
- grid.10025.360000 0004 1936 8470Department of Psychological Sciences, Institute of Psychology, Health and Society, University of Liverpool, Liverpool, L69 3BX UK
| |
Collapse
|
11
|
The attentional blink unveils the interplay between conscious perception, spatial attention and working memory encoding. Conscious Cogn 2020; 85:103008. [PMID: 32906024 DOI: 10.1016/j.concog.2020.103008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/07/2020] [Accepted: 08/24/2020] [Indexed: 11/20/2022]
Abstract
Our ability to perceive two events in close temporal succession is severely limited, a phenomenon known as the attentional blink. While the blink has served as a popular tool to prevent conscious perception, there is less research on its causes, and in particular on the role of conscious perception of the first event in triggering it. In three experiments, we disentangled the roles of spatial attention, conscious perception and working memory (WM) in causing the blink. We show that while allocating spatial attention to T1 is neither necessary nor sufficient for eliciting a blink, consciously perceiving it is necessary but not sufficient. When T1 was task irrelevant, consciously perceiving it triggered a blink only when it matched the attentional set for T2. We conclude that consciously perceiving a task-relevant event causes the blink, possibly because it triggers encoding of this event into WM. We discuss the implications of these findings for the relationship between spatial attention, conscious perception and WM, as well as for the distinction between access and phenomenal consciousness.
Collapse
|
12
|
Keppler J. The Common Basis of Memory and Consciousness: Understanding the Brain as a Write-Read Head Interacting With an Omnipresent Background Field. Front Psychol 2020; 10:2968. [PMID: 31998199 PMCID: PMC6966770 DOI: 10.3389/fpsyg.2019.02968] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 12/16/2019] [Indexed: 12/27/2022] Open
Abstract
The main goal of this article consists in addressing two fundamental issues of consciousness research and cognitive science, namely, the question of why declarative memory functions are inextricably linked with phenomenal awareness and the question of the physical basis of memory traces. The presented approach proposes that high-level cognitive processes involving consciousness employ a universal mechanism by means of which they access and modulate an omnipresent background field that is identified with the zero-point field (ZPF) specified by stochastic electrodynamics (SED), a branch of physics that deals with the universal principles underlying quantum systems. In addition to its known physical properties and memory capacities, the ZPF is hypothesized to be an immanently sentient medium. It is propounded that linking up to a particular field mode of the ZPF activates a particular phenomenal nuance, implying that the phase-locked coupling of a set of field modes, i.e., the formation of a so-called ZPF information state, constitutes an appropriate mechanism for the amalgamation of elementary shades of consciousness into a complex state of consciousness. Since quantum systems rest exactly on this mechanism, conscious memory processes in the brain are expected to differ from unconscious processes by the presence of the typical features of many-body quantum systems, particularly long-range coherence and attractor formation, which is supported by a huge body of empirical evidence. On this basis, the conceptual framework set out in this article paves the way for a new understanding of the brain as a write-read head interacting with the ZPF, leading to self-consistent interpretations of the neural correlates of memory formation and memory retrieval and explaining why these memory processes are closely intertwined with phenomenal awareness. In particular, the neural correlates suggest that the brain produces consciously perceived memory traces by writing sequences of information states into the ZPF and retrieves consciously experienced memory traces by reading sequences of information states from the ZPF. Using these theoretical foundations, altered states of consciousness and memory disorders can be traced back to impairments of the ZPF write-read mechanism. The mechanism should reveal itself through characteristic photon emissions, resulting in testable predictions.
Collapse
|
13
|
Working memory can compare two visual items without accessing visual consciousness. Conscious Cogn 2019; 78:102859. [PMID: 31896030 DOI: 10.1016/j.concog.2019.102859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 11/30/2019] [Accepted: 12/03/2019] [Indexed: 11/22/2022]
Abstract
Recent studies argued that unconscious visual information could access the working memory, however, it is still unclear whether the central executive could be activated unconsciously. We investigated, using a delayed match-to-sample task, whether the central executive is an unconscious process. In the experiment of the present study, participants were asked to compare the locations of two given visual targets. Both targets (or one of the two targets, depending on the experimental condition) were masked by a visual masking paradigm. The results showed an above-chance-level performance even in the condition that participants compared two unconscious targets. However, when the trials with the non-visual conscious experience of the target were removed from the analysis, the performance was no longer significantly different from chance level. Our results suggest that the central executive could be activated unconsciously by some level of stimulus signal, that is still below the threshold for a subjective report.
Collapse
|
14
|
Jang JH, Kim J, Park G, Kim H, Jung ES, Cha JY, Kim CY, Kim S, Lee JH, Yoo H. Beta wave enhancement neurofeedback improves cognitive functions in patients with mild cognitive impairment: A preliminary pilot study. Medicine (Baltimore) 2019; 98:e18357. [PMID: 31852140 PMCID: PMC6922450 DOI: 10.1097/md.0000000000018357] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Mild cognitive impairment (MCI) is a symptom characterizing cognitive decline and a transitional state between normal aging and dementia; however, there is no definitive diagnosis and treatment for MCI. Neurofeedback (NF), which is a training mechanism that employs operant conditioning to regulate brain activity, has been increasingly investigated concerning its beneficial effects for dementia and MCI. METHODS This study investigated cognitive improvement and hemodynamic changes in the prefrontal cortex (PFC) following NF training in patients with MCI. Five patients with MCI received NF training for enhanced beta band activity in the dorsolateral PFC-16 sessions for 8 weeks-with each session divided into 9 5-minute trials. The primary outcome measure was a cognitive assessment tool: the Korean version of the Montreal Cognitive Assessment. The secondary outcome measures were the Central Nervous System Vital Signs for neurocognitive testing, hemodynamic changes using functional near-infrared spectroscopy in the PFC during a working-memory task, and Beck Depression Inventory scores. RESULTS After completing the training, patients' cognitive function significantly improved in domains such as composite memory, cognitive flexibility, complex attention, reaction time, and executive function. Increased electroencephalogram beta power was observed over NF training sessions (Spearman rank correlation test: r = 0.746, P = .001). The threshold value for gaining positive feedback from pre-NF baseline on beta power significantly increased (Spearman rank correlation test: r = 0.805, P = .001). Hemodynamic response in PFC changed after NF training, and individual differences were identified. Specifically, hypoactivation of the hemodynamic response by emotional distraction recovered following NF training. CONCLUSION We suggest that patients' cognitive processing efficiency was improved by the NF training. These beneficial results suggest that NF training may have potential therapeutic applications to prevent the progression from MCI to dementia. TRIAL REGISTRATION NUMBER Clinical Research Information Service (KCT0003433).
Collapse
Affiliation(s)
- Jung-Hee Jang
- Department of Neurologic Disorders & Aging Brain Constitution, Dunsan Korean Medicine Hospital, Daejeon University
| | - Jieun Kim
- Clinical Medicine Division, Korea Institute of Oriental Medicine
| | - Gunhyuk Park
- Herbal Medicine Resources Research Center, Korea Institute of Oriental Medicine, Naju-si, Jeollanam-do, Republic of Korea
| | - Haesook Kim
- Department of Neurologic Disorders & Aging Brain Constitution, Dunsan Korean Medicine Hospital, Daejeon University
| | - Eun-Sun Jung
- Department of Neurologic Disorders & Aging Brain Constitution, Dunsan Korean Medicine Hospital, Daejeon University
| | - Ji-yun Cha
- Department of Neurologic Disorders & Aging Brain Constitution, Dunsan Korean Medicine Hospital, Daejeon University
| | - Chan-young Kim
- Department of Neurologic Disorders & Aging Brain Constitution, Dunsan Korean Medicine Hospital, Daejeon University
| | - Siyeon Kim
- Department of Neurologic Disorders & Aging Brain Constitution, Dunsan Korean Medicine Hospital, Daejeon University
| | - Jun-Hwan Lee
- Clinical Medicine Division, Korea Institute of Oriental Medicine
| | - Horyong Yoo
- Department of Neurologic Disorders & Aging Brain Constitution, Dunsan Korean Medicine Hospital, Daejeon University
| |
Collapse
|
15
|
Bourbon-Teles J, Soto D. Assessing the Role of the Left Dorsal Frontal Cortex in Working Memory Guidance: Attentional or Mnemonic? A Neurostimulation Study. Neuroscience 2019; 411:140-149. [DOI: 10.1016/j.neuroscience.2019.04.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 04/17/2019] [Accepted: 04/28/2019] [Indexed: 12/30/2022]
|
16
|
Sheikh UA, Carreiras M, Soto D. Decoding the meaning of unconsciously processed words using fMRI-based MVPA. Neuroimage 2019; 191:430-440. [DOI: 10.1016/j.neuroimage.2019.02.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/22/2019] [Accepted: 02/05/2019] [Indexed: 11/30/2022] Open
|
17
|
Tanaka G, Yamane T, Héroux JB, Nakane R, Kanazawa N, Takeda S, Numata H, Nakano D, Hirose A. Recent advances in physical reservoir computing: A review. Neural Netw 2019; 115:100-123. [PMID: 30981085 DOI: 10.1016/j.neunet.2019.03.005] [Citation(s) in RCA: 301] [Impact Index Per Article: 60.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 02/24/2019] [Accepted: 03/07/2019] [Indexed: 02/06/2023]
Abstract
Reservoir computing is a computational framework suited for temporal/sequential data processing. It is derived from several recurrent neural network models, including echo state networks and liquid state machines. A reservoir computing system consists of a reservoir for mapping inputs into a high-dimensional space and a readout for pattern analysis from the high-dimensional states in the reservoir. The reservoir is fixed and only the readout is trained with a simple method such as linear regression and classification. Thus, the major advantage of reservoir computing compared to other recurrent neural networks is fast learning, resulting in low training cost. Another advantage is that the reservoir without adaptive updating is amenable to hardware implementation using a variety of physical systems, substrates, and devices. In fact, such physical reservoir computing has attracted increasing attention in diverse fields of research. The purpose of this review is to provide an overview of recent advances in physical reservoir computing by classifying them according to the type of the reservoir. We discuss the current issues and perspectives related to physical reservoir computing, in order to further expand its practical applications and develop next-generation machine learning systems.
Collapse
Affiliation(s)
- Gouhei Tanaka
- Institute for Innovation in International Engineering Education, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan; Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
| | | | | | - Ryosho Nakane
- Institute for Innovation in International Engineering Education, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan; Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | | | | | | | | | - Akira Hirose
- Institute for Innovation in International Engineering Education, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan; Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| |
Collapse
|
18
|
Persuh M, LaRock E, Berger J. Working Memory and Consciousness: The Current State of Play. Front Hum Neurosci 2018; 12:78. [PMID: 29551967 PMCID: PMC5840147 DOI: 10.3389/fnhum.2018.00078] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 02/12/2018] [Indexed: 12/24/2022] Open
Abstract
Working memory (WM), an important posit in cognitive science, allows one to temporarily store and manipulate information in the service of ongoing tasks. WM has been traditionally classified as an explicit memory system-that is, as operating on and maintaining only consciously perceived information. Recently, however, several studies have questioned this assumption, purporting to provide evidence for unconscious WM. In this article, we focus on visual working memory (VWM) and critically examine these studies as well as studies of unconscious perception that seem to provide indirect evidence for unconscious WM. Our analysis indicates that current evidence does not support an unconscious WM store, though we offer independent reasons to think that WM may operate on unconsciously perceived information.
Collapse
Affiliation(s)
- Marjan Persuh
- Department of Social Sciences, Human Services and Criminal Justice, Borough of Manhattan Community College, City University of New York, New York, NY, United States
| | - Eric LaRock
- Department of Philosophy, 751 Mathematics and Science Center, Oakland University, Rochester, MI, United States
| | - Jacob Berger
- Department of English and Philosophy, Idaho State University, Pocatello, ID, United States
| |
Collapse
|
19
|
Velichkovsky BB. Consciousness and working memory: Current trends and research perspectives. Conscious Cogn 2017; 55:35-45. [DOI: 10.1016/j.concog.2017.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 07/12/2017] [Accepted: 07/17/2017] [Indexed: 11/25/2022]
|
20
|
Ji E, Lee KM, Kim MS. Independent operation of implicit working memory under cognitive load. Conscious Cogn 2017; 55:214-222. [PMID: 28892738 DOI: 10.1016/j.concog.2017.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 08/18/2017] [Accepted: 08/30/2017] [Indexed: 10/18/2022]
Abstract
Implicit working memory (WM) has been known to operate non-consciously and unintentionally. The current study investigated whether implicit WM is a discrete mechanism from explicit WM in terms of cognitive resource. To induce cognitive resource competition, we used a conjunction search task (Experiment 1) and imposed spatial WM load (Experiment 2a and 2b). Each trial was composed of a set of five consecutive search displays. The location of the first four displays appeared as per pre-determined patterns, but the fifth display could follow the same pattern or not. If implicit WM can extract the moving pattern of stimuli, response times for the fifth target would be faster when it followed the pattern compared to when it did not. Our results showed implicit WM can operate when participants are searching for the conjunction target and even while maintaining spatial WM information. These results suggest that implicit WM is independent from explicit spatial WM.
Collapse
Affiliation(s)
- Eunhee Ji
- Department of Psychology, Yonsei University, Republic of Korea
| | - Kyung Min Lee
- Department of Psychology, Yonsei University, Republic of Korea
| | - Min-Shik Kim
- Department of Psychology, Yonsei University, Republic of Korea.
| |
Collapse
|
21
|
Goldstein A, Hassin RR. Commentary: Definitely maybe: can unconscious processes perform the same functions as conscious processes? Front Psychol 2017; 8:1230. [PMID: 28824475 PMCID: PMC5543087 DOI: 10.3389/fpsyg.2017.01230] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 07/05/2017] [Indexed: 11/21/2022] Open
Affiliation(s)
- Ariel Goldstein
- Cognitive Science Department, Hebrew UniversityJerusalem, Israel
| | - Ran R. Hassin
- Psychology Department, Hebrew UniversityJerusalem, Israel
- Cognitive Science Department, Center for the Study of Rationality, Hebrew UniversityJerusalem, Israel
| |
Collapse
|
22
|
Bergström F, Eriksson J. Neural Evidence for Non-conscious Working Memory. Cereb Cortex 2017; 28:3217-3228. [DOI: 10.1093/cercor/bhx193] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Indexed: 12/24/2022] Open
Affiliation(s)
- Fredrik Bergström
- Umeå center for Functional Brain Imaging (UFBI), Umeå University, Sweden
- Department of Integrative Medical Biology, Physiology Section, Umeå University, Sweden
- Faculty of Psychology and Educational Sciences, University of Coimbra, Portugal
| | - Johan Eriksson
- Umeå center for Functional Brain Imaging (UFBI), Umeå University, Sweden
- Department of Integrative Medical Biology, Physiology Section, Umeå University, Sweden
| |
Collapse
|
23
|
Trübutschek D, Marti S, Ojeda A, King JR, Mi Y, Tsodyks M, Dehaene S. A theory of working memory without consciousness or sustained activity. eLife 2017; 6:e23871. [PMID: 28718763 PMCID: PMC5589417 DOI: 10.7554/elife.23871] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 07/13/2017] [Indexed: 01/22/2023] Open
Abstract
Working memory and conscious perception are thought to share similar brain mechanisms, yet recent reports of non-conscious working memory challenge this view. Combining visual masking with magnetoencephalography, we investigate the reality of non-conscious working memory and dissect its neural mechanisms. In a spatial delayed-response task, participants reported the location of a subjectively unseen target above chance-level after several seconds. Conscious perception and conscious working memory were characterized by similar signatures: a sustained desynchronization in the alpha/beta band over frontal cortex, and a decodable representation of target location in posterior sensors. During non-conscious working memory, such activity vanished. Our findings contradict models that identify working memory with sustained neural firing, but are compatible with recent proposals of 'activity-silent' working memory. We present a theoretical framework and simulations showing how slowly decaying synaptic changes allow cell assemblies to go dormant during the delay, yet be retrieved above chance-level after several seconds.
Collapse
Affiliation(s)
- Darinka Trübutschek
- Ecole des Neurosciences de Paris Ile-de-France, 15 rue de l'Ecole de médecine, Paris, France
- Université Pierre et Marie Curie, 4 Place Jussieu, Paris, France
- Cognitive Neuroimaging Unit, CEA DSV/I2BM, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin center, Gif/Yvette, France
| | - Sébastien Marti
- Cognitive Neuroimaging Unit, CEA DSV/I2BM, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin center, Gif/Yvette, France
| | - Andrés Ojeda
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Jean-Rémi King
- Department of Psychology, New York University, New York, United States
- Frankfurt Institute for Advanced Studies, Frankfurt, Germany
| | - Yuanyuan Mi
- Brain Science Center, Institute of Basic Medical Sciences, Beijing, China
| | - Misha Tsodyks
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
- Department of Neuroscience, Columbia University, New York, United States
| | - Stanislas Dehaene
- Cognitive Neuroimaging Unit, CEA DSV/I2BM, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin center, Gif/Yvette, France
- Collège de France, 11 Place Marcelin Berthelot, Paris, France
| |
Collapse
|
24
|
King JR, Pescetelli N, Dehaene S. Brain Mechanisms Underlying the Brief Maintenance of Seen and Unseen Sensory Information. Neuron 2017; 92:1122-1134. [PMID: 27930903 DOI: 10.1016/j.neuron.2016.10.051] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 07/05/2016] [Accepted: 10/21/2016] [Indexed: 01/24/2023]
Abstract
Recent evidence of unconscious working memory challenges the notion that only visible stimuli can be actively maintained over time. In the present study, we investigated the neural dynamics underlying the maintenance of variably visible stimuli using magnetoencephalography. Subjects had to detect and mentally maintain the orientation of a masked grating. We show that the stimulus is fully encoded in early brain activity independently of visibility reports. However, the presence and orientation of the target are actively maintained throughout the brief retention period, even when the stimulus is reported as unseen. Source and decoding analyses revealed that perceptual maintenance recruits a hierarchical network spanning the early visual, temporal, parietal, and frontal cortices. Importantly, the representations coded in the late processing stages of this network specifically predicted visibility reports. These unexpected results challenge several theories of consciousness and suggest that invisible information can be briefly maintained within the higher processing stages of visual perception.
Collapse
Affiliation(s)
- Jean-Rémi King
- Department of Psychology, New York University, New York, NY 10003, USA; Neuroscience Department, Frankfurt Institute for Advanced Studies, 60438 Frankfurt, Germany.
| | - Niccolo Pescetelli
- Department of Experimental Psychology, University of Oxford, OX1 3UD Oxford, UK
| | - Stanislas Dehaene
- Cognitive Neuroimaging Unit, CEA DSV/I2BM, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin Center, 91191 Gif/Yvette, France; Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France
| |
Collapse
|
25
|
Chiau HY, Muggleton NG, Juan CH. Exploring the contributions of the supplementary eye field to subliminal inhibition using double-pulse transcranial magnetic stimulation. Hum Brain Mapp 2016; 38:339-351. [PMID: 27611342 DOI: 10.1002/hbm.23364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 08/22/2016] [Accepted: 08/22/2016] [Indexed: 11/09/2022] Open
Abstract
It is widely accepted that the supplementary eye fields (SEF) are involved in the control of voluntary eye movements. However, recent evidence suggests that SEF may also be important for unconscious and involuntary motor processes. Indeed, Sumner et al. ([2007]: Neuron 54:697-711) showed that patients with micro-lesions of the SEF demonstrated an absence of subliminal inhibition as evoked by masked-prime stimuli. Here, we used double-pulse transcranial magnetic stimulation (TMS) in healthy volunteers to investigate the role of SEF in subliminal priming. We applied double-pulse TMS at two time windows in a masked-prime task: the first during an early phase, 20-70 ms after the onset of the mask but before target presentation, during which subliminal inhibition is present; and the second during a late phase, 20-70 ms after target onset, during which the saccade is being prepared. We found no effect of TMS with the early time window of stimulation, whereas a reduction in the benefit of an incompatible subliminal prime stimulus was found when SEF TMS was applied at the late time window. These findings suggest that there is a role for SEF related to the effects of subliminal primes on eye movements, but the results do not support a role in inhibiting the primed tendency. Hum Brain Mapp 38:339-351, 2017. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Hui-Yan Chiau
- Institute of Cognitive Neuroscience, National Central University, Jhongli, Taiwan.,Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
| | - Neil G Muggleton
- Institute of Cognitive Neuroscience, National Central University, Jhongli, Taiwan.,Institute of Cognitive Neuroscience, University College London, London, United Kingdom.,Department of Psychology, Goldsmiths, University of London, New Cross, London, United Kingdom
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Jhongli, Taiwan
| |
Collapse
|
26
|
Soto D, Silvanto J. Is conscious awareness needed for all working memory processes? Neurosci Conscious 2016; 2016:niw009. [PMID: 30109128 PMCID: PMC6084557 DOI: 10.1093/nc/niw009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/25/2016] [Accepted: 05/31/2016] [Indexed: 11/30/2022] Open
Abstract
Stein and colleagues argue there is no yet conclusive evidence for nonconscious working memory (WM) and that is critical to probe WM while ensuring null sensitivity to memory cues. While this stringent approach reduces the likelihood of nonconscious signaling for WM, we discuss existing work meeting this null sensitivity criteria, and, related work on nonconscious cognition in keeping with WM/awareness dissociations on the basis of a functional operational definition of WM. Further, because it is likely that WM is a nonunitary functional construct and visual awareness a gradual phenomenon, we propose that delineating the neural mechanisms for distinct WM types across different levels of awareness may prove the most fruitful approach for understanding the interplay between WM and consciousness.
Collapse
Affiliation(s)
- David Soto
- Basque Center on Cognition, Brain and Language, San Sebastian, Spain
- Basque Foundation for Science, Ikerbasque, Bilbao, Spain; and
| | - Juha Silvanto
- Department of Psychology, Faculty of Science and Technology, University of Westminster, London, UK
| |
Collapse
|
27
|
Samaha J, Barrett JJ, Sheldon AD, LaRocque JJ, Postle BR. Dissociating Perceptual Confidence from Discrimination Accuracy Reveals No Influence of Metacognitive Awareness on Working Memory. Front Psychol 2016; 7:851. [PMID: 27375529 PMCID: PMC4893488 DOI: 10.3389/fpsyg.2016.00851] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/23/2016] [Indexed: 11/23/2022] Open
Abstract
Visual awareness is hypothesized to be intimately related to visual working memory (WM), such that information present in WM is thought to have necessarily been represented consciously. Recent work has challenged this longstanding view by demonstrating that visual stimuli rated by observers as unseen can nevertheless be maintained over a delay period. These experiments have been criticized, however, on the basis that subjective awareness ratings may contain response bias (e.g., an observer may report no awareness when in fact they had partial awareness). We mitigated this issue by investigating WM for visual stimuli that were matched for perceptual discrimination capacity (d'), yet which varied in subjective confidence ratings (so-called relative blindsight). If the degree of initial subjective awareness of a stimulus facilitates later maintenance of that information, WM performance should improve for stimuli encoded with higher confidence. In contrast, we found that WM performance did not benefit from higher visual discrimination confidence. This relationship was observed regardless of WM load (1 or 3). Insofar as metacognitive ratings (e.g., confidence, visibility) reflect visual awareness, these results challenge a strong relationship between conscious perception and WM using a paradigm that controls for discrimination accuracy and is less subject to response bias (since confidence is manipulated within subjects). Methodologically, we replicate prior efforts to induce relative blindsight using similar stimulus displays, providing a general framework for isolating metacognitive awareness in order to examine the function of consciousness.
Collapse
Affiliation(s)
- Jason Samaha
- Department of Psychology, University of Wisconsin–Madison, MadisonWI, USA
| | - John J. Barrett
- Department of Psychology, University of Wisconsin–Madison, MadisonWI, USA
| | - Andrew D. Sheldon
- Medical Scientist Training Program and Neuroscience Training Program, University of Wisconsin–Madison, MadisonWI, USA
| | - Joshua J. LaRocque
- Medical Scientist Training Program and Neuroscience Training Program, University of Wisconsin–Madison, MadisonWI, USA
| | - Bradley R. Postle
- Department of Psychology, University of Wisconsin–Madison, MadisonWI, USA
- Department of Psychiatry, University of Wisconsin–Madison, MadisonWI, USA
| |
Collapse
|
28
|
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.
Collapse
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
| |
Collapse
|
29
|
Stein T, Kaiser D, Hesselmann G. Can working memory be non-conscious? Neurosci Conscious 2016; 2016:niv011. [PMID: 30774983 PMCID: PMC6368269 DOI: 10.1093/nc/niv011] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/04/2015] [Accepted: 12/08/2015] [Indexed: 11/13/2022] Open
Abstract
Working memory (WM) is closely linked to conscious awareness: In most conceptions of WM, the inputs to WM need to be conscious. The findings of some recent studies, however, have been taken to suggest that WM can indeed operate on non-conscious inputs. Here, we argue that these findings can easily be accommodated by conventional conceptions of non-conscious perception and conscious WM. We conclude that these studies do not provide conclusive evidence for non-conscious WM. It is thus too early to dismiss the traditional view of a tight link between WM and conscious awareness.
Collapse
Affiliation(s)
- Timo Stein
- Center for Mind/Brain Sciences (CIMeC), University of Trento, 38068 Rovereto, Italy and
| | - Daniel Kaiser
- Center for Mind/Brain Sciences (CIMeC), University of Trento, 38068 Rovereto, Italy and
| | - Guido Hesselmann
- Visual Perception Laboratory, Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin, 10117 Berlin, Germany
| |
Collapse
|
30
|
Jacob J, Jacobs C, Silvanto J. Attention, working memory, and phenomenal experience of WM content: memory levels determined by different types of top-down modulation. Front Psychol 2015; 6:1603. [PMID: 26539145 PMCID: PMC4610135 DOI: 10.3389/fpsyg.2015.01603] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 10/05/2015] [Indexed: 11/29/2022] Open
Abstract
What is the role of top-down attentional modulation in consciously accessing working memory (WM) content? In influential WM models, information can exist in different states, determined by allocation of attention; placing the original memory representation in the center of focused attention gives rise to conscious access. Here we discuss various lines of evidence indicating that such attentional modulation is not sufficient for memory content to be phenomenally experienced. We propose that, in addition to attentional modulation of the memory representation, another type of top-down modulation is required: suppression of all incoming visual information, via inhibition of early visual cortex. In this view, there are three distinct memory levels, as a function of the top-down control associated with them: (1) Nonattended, nonconscious associated with no attentional modulation; (2) attended, phenomenally nonconscious memory, associated with attentional enhancement of the actual memory trace; (3) attended, phenomenally conscious memory content, associated with enhancement of the memory trace and top-down suppression of all incoming visual input.
Collapse
Affiliation(s)
- Jane Jacob
- Department of Psychology, Faculty of Science and Technology, University of Westminster , London, UK
| | - Christianne Jacobs
- Department of Psychology, Faculty of Science and Technology, University of Westminster , London, UK
| | - Juha Silvanto
- Department of Psychology, Faculty of Science and Technology, University of Westminster , London, UK
| |
Collapse
|
31
|
Bergström F, Eriksson J. The conjunction of non-consciously perceived object identity and spatial position can be retained during a visual short-term memory task. Front Psychol 2015; 6:1470. [PMID: 26483726 PMCID: PMC4588213 DOI: 10.3389/fpsyg.2015.01470] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/14/2015] [Indexed: 11/13/2022] Open
Abstract
Although non-consciously perceived information has previously been assumed to be short-lived (< 500 ms), recent findings show that non-consciously perceived information can be maintained for at least 15 s. Such findings can be explained as working memory without a conscious experience of the information to be retained. However, whether or not working memory can operate on non-consciously perceived information remains controversial, and little is known about the nature of such non-conscious visual short-term memory (VSTM). Here we used continuous flash suppression to render stimuli non-conscious, to investigate the properties of non-consciously perceived representations in delayed match-to-sample (DMS) tasks. In Experiment I we used variable delays (5 or 15 s) and found that performance was significantly better than chance and was unaffected by delay duration, thereby replicating previous findings. In Experiment II the DMS task required participants to combine information of spatial position and object identity on a trial-by-trial basis to successfully solve the task. We found that the conjunction of spatial position and object identity was retained, thereby verifying that non-conscious, trial-specific information can be maintained for prospective use. We conclude that our results are consistent with a working memory interpretation, but that more research is needed to verify this interpretation.
Collapse
Affiliation(s)
- Fredrik Bergström
- Umeå Center for Functional Brain Imaging, Umeå University Umeå, Sweden ; Department of Integrative Medical Biology, Physiology Section, Umeå University Umeå, Sweden
| | - Johan Eriksson
- Umeå Center for Functional Brain Imaging, Umeå University Umeå, Sweden ; Department of Integrative Medical Biology, Physiology Section, Umeå University Umeå, Sweden
| |
Collapse
|
32
|
The state of a central inhibition system predicts access to visual targets: An ERP study on distractor-induced blindness (DIB). Conscious Cogn 2015; 35:308-18. [DOI: 10.1016/j.concog.2015.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/29/2015] [Accepted: 02/03/2015] [Indexed: 11/19/2022]
|
33
|
Wu Q, Lo Voi JTH, Lee TY, Mackie MA, Wu Y, Fan J. Interocular suppression prevents interference in a flanker task. Front Psychol 2015; 6:1110. [PMID: 26321969 PMCID: PMC4531229 DOI: 10.3389/fpsyg.2015.01110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/20/2015] [Indexed: 11/17/2022] Open
Abstract
Executive control of attention refers to processes that detect and resolve conflict among competing thoughts and actions. Despite the high-level nature of this faculty, the role of awareness in executive control of attention is not well understood. In this study, we used interocular suppression to mask the flankers in an arrow flanker task, in which the flankers and the target arrow were presented simultaneously in order to elicit executive control of attention. Participants were unable to detect the flanker arrows or to reliably identify their direction when masked. There was a typical conflict effect (prolonged reaction time and increased error rate under flanker-target incongruent condition compared to congruent condition) when the flanker arrows were unmasked, while the conflict effect was absent when the flanker arrows were masked with interocular suppression. These results suggest that blocking awareness of competing stimuli with interocular suppression prevents the involvement of executive control of attention.
Collapse
Affiliation(s)
- Qiong Wu
- Department of Psychology, Peking University , Beijing, China
| | - Jonathan T H Lo Voi
- The Graduate Center, City University of New York , New York, NY, USA ; Department of Psychology, Queens College, City University of New York , Queens, NY, USA
| | - Thomas Y Lee
- Department of Psychology, Queens College, City University of New York , Queens, NY, USA
| | - Melissa-Ann Mackie
- The Graduate Center, City University of New York , New York, NY, USA ; Department of Psychology, Queens College, City University of New York , Queens, NY, USA
| | - Yanhong Wu
- Department of Psychology, Peking University , Beijing, China ; Beijing Key Laboratory of Behavior and Mental Health, Peking University , Beijing, China ; Key Laboratory of Machine Perception (Ministry of Education), Peking University , Beijing, China
| | - Jin Fan
- The Graduate Center, City University of New York , New York, NY, USA ; Department of Psychology, Queens College, City University of New York , Queens, NY, USA ; Department of Psychiatry, Icahn School of Medicine at Mount Sinai , New York, NY, USA ; Department of Neuroscience, Icahn School of Medicine at Mount Sinai , New York, NY, USA
| |
Collapse
|
34
|
Martini M, Sachse P, Furtner MR, Gaschler R. Why should working memory be related to incidentally learned sequence structures? Cortex 2015; 64:407-10. [DOI: 10.1016/j.cortex.2014.05.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 05/23/2014] [Indexed: 11/16/2022]
|
35
|
Bergström F, Eriksson J. Maintenance of non-consciously presented information engages the prefrontal cortex. Front Hum Neurosci 2014; 8:938. [PMID: 25484862 PMCID: PMC4240068 DOI: 10.3389/fnhum.2014.00938] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 11/04/2014] [Indexed: 01/22/2023] Open
Abstract
Conscious processing is generally seen as required for flexible and willful actions, as well as for tasks that require durable information maintenance. Here we present research that questions the assumption that only consciously perceived information is durable (>500 ms). Using the attentional blink (AB) phenomenon, we rendered otherwise relatively clearly perceived letters non-conscious. In a first experiment we systematically manipulated the delay between stimulus presentation and response, for the purpose of estimating the durability of non-conscious perceptual representations. For items reported not seen, we found that behavioral performance was better than chance across intervals up to 15 s. In a second experiment we used fMRI to investigate the neural correlates underlying the maintenance of non-conscious perceptual representations. Critically, the relatively long delay period demonstrated in experiment 1 enabled isolation of the signal change specifically related to the maintenance period, separate from stimulus presentation and response. We found sustained BOLD signal change in the right mid-lateral prefrontal cortex, orbitofrontal cortex, and crus II of the cerebellum during maintenance of non-consciously perceived information. These findings are consistent with the controversial claim that working-memory mechanisms are involved in the short-term maintenance of non-conscious perceptual representations.
Collapse
Affiliation(s)
- Fredrik Bergström
- Umeå center for Functional Brain Imaging (UFBI) Umeå, Sweden ; Department of Integrative Medical Biology, Physiology Section, Umeå University Umeå, Sweden
| | - Johan Eriksson
- Umeå center for Functional Brain Imaging (UFBI) Umeå, Sweden ; Department of Integrative Medical Biology, Physiology Section, Umeå University Umeå, Sweden
| |
Collapse
|
36
|
Reappraising the relationship between working memory and conscious awareness. Trends Cogn Sci 2014; 18:520-5. [PMID: 25070269 DOI: 10.1016/j.tics.2014.06.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 05/27/2014] [Accepted: 06/16/2014] [Indexed: 11/22/2022]
Abstract
Classically, the operation of working memory (WM) has been strongly coupled with conscious states; it is thought that WM operates on conscious input and that we are conscious of the contents and operations of WM. Here, we re-evaluate the relationship between WM and conscious awareness in light of current data and question the views that awareness is mandatory for the operation of WM and that WM contents are necessarily linked to experiential states that are consciously accessible for perceptual report. We propose a novel framework for the relationship between WM and conscious awareness.
Collapse
|