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Filimonov D, Tanskanen S, Revonsuo A, Koivisto M. Is auditory awareness graded or dichotomous: Electrophysiological correlates of consciousness at different depths of stimulus processing. Conscious Cogn 2024; 123:103720. [PMID: 38901129 DOI: 10.1016/j.concog.2024.103720] [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: 11/15/2023] [Revised: 06/12/2024] [Accepted: 06/12/2024] [Indexed: 06/22/2024]
Abstract
The level-of-processing (LoP) hypothesis postulates that transition from unaware to aware visual stimuli is either graded or dichotomous depending on the depth of stimulus processing. Humans can be progressively aware of the low-level features, such as colors or shapes, while the high-level features, such as semantic category, enter consciousness in an all-or none fashion. Unlike in vision, sounds always unfold in time, which might require mechanisms dissimilar from visual processing. We tested the LoP hypothesis in hearing for the first time by presenting participants with words of different categories, spoken in different pitches near the perceptual threshold. We also assessed whether different electrophysiological correlates of consciousness, the auditory awareness negativity (AAN) and late positivity (LP), were associated with LoP. Our findings indicate that LoP also applies to the auditory modality. AAN is an early correlate of awareness independent of LoP, while LP was modulated by awareness, performance accuracy and the level of processing.
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Affiliation(s)
- Dmitri Filimonov
- Department of Psychology, University of Turku, Finland; Turku Brain and Mind Centre, University of Turku, Finland.
| | - Sampo Tanskanen
- Faculty of Medicine, University of Turku, Finland; Turku Brain and Mind Centre, University of Turku, Finland
| | - Antti Revonsuo
- Department of Psychology, University of Turku, Finland; Turku Brain and Mind Centre, University of Turku, Finland; Division of Cognitive Neuroscience and Philosophy, University of Skövde, Sweden
| | - Mika Koivisto
- Department of Psychology, University of Turku, Finland; Turku Brain and Mind Centre, University of Turku, Finland
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Doradzińska Ł, Bola M. Early Electrophysiological Correlates of Perceptual Consciousness Are Affected by Both Exogenous and Endogenous Attention. J Cogn Neurosci 2024; 36:1297-1324. [PMID: 38579265 DOI: 10.1162/jocn_a_02156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
It has been proposed that visual awareness negativity (VAN), which is an early ERP component, constitutes a neural correlate of visual consciousness that is independent of perceptual and cognitive mechanisms. In the present study, we investigated whether VAN is indeed a specific marker of phenomenal awareness or rather reflects the involvement of attention. To this end, we reanalyzed data collected in a previously published EEG experiment in which awareness of visual stimuli and two aspects that define attentional involvement, namely, the inherent saliency and task relevance of a stimulus, were manipulated orthogonally. During the experimental procedure, participants (n = 41) were presented with images of faces that were backward-masked or unmasked, fearful or neutral, and defined as task-relevant targets or task-irrelevant distractors. Single-trial ERP analysis revealed that VAN was highly dependent on attentional manipulations in the early time window (140-200 msec), up to the point that the effect of awareness was not observed for attentionally irrelevant stimuli (i.e., neutral faces presented as distractors). In the late time window (200-350 msec), VAN was present in all attentional conditions, but its amplitude was significantly higher in response to fearful faces and task-relevant face images than in response to neutral ones and task-irrelevant ones, respectively. In conclusion, we demonstrate that the amplitude of VAN is highly dependent on both exogenous (stimulus saliency) and endogenous attention (task requirements). Our results challenge the view that VAN constitutes an attention-independent correlate of phenomenal awareness.
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Affiliation(s)
- Łucja Doradzińska
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Michał Bola
- Centre for Brain Research, Jagiellonian University, Krakow, Poland
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Wu M, Auksztulewicz R, Riecke L. Multimodal acoustic-electric trigeminal nerve stimulation modulates conscious perception. Neuroimage 2024; 285:120476. [PMID: 38030051 DOI: 10.1016/j.neuroimage.2023.120476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 11/05/2023] [Accepted: 11/26/2023] [Indexed: 12/01/2023] Open
Abstract
Multimodal stimulation can reverse pathological neural activity and improve symptoms in neuropsychiatric diseases. Recent research shows that multimodal acoustic-electric trigeminal-nerve stimulation (TNS) (i.e., musical stimulation synchronized to electrical stimulation of the trigeminal nerve) can improve consciousness in patients with disorders of consciousness. However, the reliability and mechanism of this novel approach remain largely unknown. We explored the effects of multimodal acoustic-electric TNS in healthy human participants by assessing conscious perception before and after stimulation using behavioral and neural measures in tactile and auditory target-detection tasks. To explore the mechanisms underlying the putative effects of acoustic-electric stimulation, we fitted a biologically plausible neural network model to the neural data using dynamic causal modeling. We observed that (1) acoustic-electric stimulation improves conscious tactile perception without a concomitant change in auditory perception, (2) this improvement is caused by the interplay of the acoustic and electric stimulation rather than any of the unimodal stimulation alone, and (3) the effect of acoustic-electric stimulation on conscious perception correlates with inter-regional connection changes in a recurrent neural processing model. These results provide evidence that acoustic-electric TNS can promote conscious perception. Alterations in inter-regional cortical connections might be the mechanism by which acoustic-electric TNS achieves its consciousness benefits.
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Affiliation(s)
- Min Wu
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 6229 EV Maastricht, the Netherlands.
| | - Ryszard Auksztulewicz
- Department of Education and Psychology, Freie Universität Berlin, Berlin 14195, Germany
| | - Lars Riecke
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 6229 EV Maastricht, the Netherlands
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Sliding Scale Theory of Attention and Consciousness/Unconsciousness. Behav Sci (Basel) 2022; 12:bs12020043. [PMID: 35200294 PMCID: PMC8869714 DOI: 10.3390/bs12020043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/17/2022] [Accepted: 01/26/2022] [Indexed: 02/01/2023] Open
Abstract
Attention defined as focusing on a unit of information plays a prominent role in both consciousness and the cognitive unconscious, due to its essential role in information processing. Existing theories of consciousness invariably address the relationship between attention and conscious awareness, ranging from attention is not required to crucial. However, these theories do not adequately or even remotely consider the contribution of attention to the cognitive unconscious. A valid theory of consciousness must also be a robust theory of the cognitive unconscious, a point rarely if ever considered. Current theories also emphasize human perceptual consciousness, primarily visual, despite evidence that consciousness occurs in diverse animal species varying in cognitive capacity, and across many forms of perceptual and thought consciousness. A comprehensive and parsimonious perspective applicable to the diversity of species demonstrating consciousness and the various forms—sliding scale theory of attention and consciousness/unconsciousness—is proposed with relevant research reviewed. Consistent with the continuous organization of natural events, attention occupies a sliding scale in regards to time and space compression. Unconscious attention in the form of the “cognitive unconscious” is time and spaced diffused, whereas conscious attention is tightly time and space compressed to the present moment. Due to the special clarity derived from brief and concentrated signals, the tight time and space compression yields conscious awareness as an emergent property. The present moment enhances the time and space compression of conscious attention, and contributes to an evolutionary explanation of conscious awareness.
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Filimonov D, Railo H, Revonsuo A, Koivisto M. Modality-specific and modality-general electrophysiological correlates of visual and auditory awareness: Evidence from a bimodal ERP experiment. Neuropsychologia 2022; 166:108154. [PMID: 35016890 DOI: 10.1016/j.neuropsychologia.2022.108154] [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: 04/07/2021] [Revised: 11/03/2021] [Accepted: 01/07/2022] [Indexed: 10/19/2022]
Abstract
To date, most studies on the event-related potential (ERP) correlates of conscious perception have examined a single perceptual modality. We compared electrophysiological correlates of visual and auditory awareness in the same experiment to test whether there are modality-specific and modality-general correlates of conscious perception. We used near threshold stimulation and analyzed event-related potentials in response to aware and unaware trials in visual, auditory and bimodal conditions. The results showed modality-specific negative amplitude correlates of conscious perception between 200 and 300 ms after stimulus onset. A combination of these auditory and visual awareness negativities was observed in the bimodal condition. A later positive amplitude difference, whose early part was modality-specific, possibly reflecting access to global workspace, and later part shared modality-general features, possibly indicating higher level cognitive processing involving the decision making, was also observed.
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Affiliation(s)
| | - Henry Railo
- Turku Brain and Mind Centre, University of Turku, Finland; Department of Clinical Neurophysiology, University of Turku, Turku, Finland
| | - Antti Revonsuo
- Department of Psychology, University of Turku, Finland; Turku Brain and Mind Centre, University of Turku, Finland; Division of Cognitive Neuroscience and Philosophy, University of Skövde, Sweden
| | - Mika Koivisto
- Department of Psychology, University of Turku, Finland; Turku Brain and Mind Centre, University of Turku, Finland
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Bachmann T. Representational 'touch' and modulatory 'retouch'-two necessary neurobiological processes in thalamocortical interaction for conscious experience. Neurosci Conscious 2021; 2021:niab045. [PMID: 34925911 PMCID: PMC8672242 DOI: 10.1093/nc/niab045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 11/16/2021] [Accepted: 11/30/2021] [Indexed: 12/01/2022] Open
Abstract
Theories of consciousness using neurobiological data or being influenced by these data have been focused either on states of consciousness or contents of consciousness. These theories have occasionally used evidence from psychophysical phenomena where conscious experience is a dependent experimental variable. However, systematic catalog of many such relevant phenomena has not been offered in terms of these theories. In the perceptual retouch theory of thalamocortical interaction, recently developed to become a blend with the dendritic integration theory, consciousness states and contents of consciousness are explained by the same mechanism. This general-purpose mechanism has modulation of the cortical layer-5 pyramidal neurons that represent contents of consciousness as its core. As a surplus, many experimental psychophysical phenomena of conscious perception can be explained by the workings of this mechanism. Historical origins and current views inherent in this theory are presented and reviewed.
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Affiliation(s)
- Talis Bachmann
- Department of Penal Law, Laboratory of Cognitive Neuroscience, School of Law, University of Tartu (Tallinn Branch), Kaarli puiestee 3, Tallinn 10119, Estonia
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Marvan T, Polák M, Bachmann T, Phillips WA. Apical amplification-a cellular mechanism of conscious perception? Neurosci Conscious 2021; 2021:niab036. [PMID: 34650815 PMCID: PMC8511476 DOI: 10.1093/nc/niab036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 07/09/2021] [Accepted: 09/23/2021] [Indexed: 11/25/2022] Open
Abstract
We present a theoretical view of the cellular foundations for network-level processes involved in producing our conscious experience. Inputs to apical synapses in layer 1 of a large subset of neocortical cells are summed at an integration zone near the top of their apical trunk. These inputs come from diverse sources and provide a context within which the transmission of information abstracted from sensory input to their basal and perisomatic synapses can be amplified when relevant. We argue that apical amplification enables conscious perceptual experience and makes it more flexible, and thus more adaptive, by being sensitive to context. Apical amplification provides a possible mechanism for recurrent processing theory that avoids strong loops. It makes the broadcasting hypothesized by global neuronal workspace theories feasible while preserving the distinct contributions of the individual cells receiving the broadcast. It also provides mechanisms that contribute to the holistic aspects of integrated information theory. As apical amplification is highly dependent on cholinergic, aminergic, and other neuromodulators, it relates the specific contents of conscious experience to global mental states and to fluctuations in arousal when awake. We conclude that apical dendrites provide a cellular mechanism for the context-sensitive selective amplification that is a cardinal prerequisite of conscious perception.
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Affiliation(s)
- Tomáš Marvan
- Department of Analytic Philosophy, Institute of Philosophy, Czech Academy of Sciences, Jilská 1, Prague 110 00, Czech Republic
| | - Michal Polák
- Department of Philosophy, University of West Bohemia, Sedláčkova 19, Pilsen 306 14, Czech Republic
| | - Talis Bachmann
- School of Law and Cognitive Neuroscience Laboratory, University of Tartu (Tallinn branch), Kaarli pst 3, Tallinn 10119, Estonia
| | - William A Phillips
- Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
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Perceptual awareness negativity: a physiological correlate of sensory consciousness. Trends Cogn Sci 2021; 25:660-670. [PMID: 34172384 DOI: 10.1016/j.tics.2021.05.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 11/21/2022]
Abstract
Much research on the neural correlates of consciousness (NCC) has focused on two evoked potentials, the P3b and the visual or auditory awareness negativity (VAN, AAN). Surveying a broad range of recent experimental evidence, we find that repeated failures to observe the P3b during conscious perception eliminate it as a putative NCC. Neither the VAN nor the AAN have been dissociated from consciousness; furthermore, a similar neural signal correlates with tactile consciousness. These awareness negativities can be maximal contralateral to the evoking stimulus, are likely generated in underlying sensory cortices, and point to the existence of a generalized perceptual awareness negativity (PAN) reflecting the onset of sensory consciousness.
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Baroni M, Frumento S, Cesari V, Gemignani A, Menicucci D, Rutigliano G. Unconscious processing of subliminal stimuli in panic disorder: A systematic review and meta-analysis. Neurosci Biobehav Rev 2021; 128:136-151. [PMID: 34139247 DOI: 10.1016/j.neubiorev.2021.06.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 02/07/2023]
Abstract
Attentional biases to threat exist in panic disorder (PD), probably related to altered subliminal processing. We systematically reviewed studies investigating subliminal processing in PD. Studies were retrieved from MEDLINE and Scopus®. We meta-analytically compared PD (n = 167) and healthy controls (HC, n = 165) for processing of masked panic-related and neutral words. We also compared subliminal and supraliminal presentations of panic-related words relative to neutral words within PD subjects and HC. We found a significantly enhanced Stroop interference to masked panic-related words in PD vs HC (Hedges' g = 0.60, p = 0.03; Q = 14.83, I2 = 66.3 %, p = 0.01). While both PD subjects and HC tended to be slower to respond to supraliminal threat words than to neutral words, PD subjects only showed a marginally significant slower response to subliminal panic-related words vs neutral words. Findings remain inconclusive regarding comparison to other mental disorders, neural correlates, and the effect of psychotherapy. Even if possibly flawed by methodological weaknesses, our findings support the existence of a sensitivity to subliminal threat cues in PD, which could be targeted to improve treatment.
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Affiliation(s)
- Marina Baroni
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy; Institute of Clinical Physiology (IFC), National Research Council, via Giuseppe Moruzzi, 1, 56124, Pisa, Italy
| | - Sergio Frumento
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Valentina Cesari
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Angelo Gemignani
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Danilo Menicucci
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy.
| | - Grazia Rutigliano
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
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Eklund R, Gerdfeldter B, Wiens S. The early but not the late neural correlate of auditory awareness reflects lateralized experiences. Neuropsychologia 2021; 158:107910. [PMID: 34090867 DOI: 10.1016/j.neuropsychologia.2021.107910] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 01/08/2023]
Abstract
Theories disagree as to whether it is the early or the late neural correlate of awareness that plays a critical role in phenomenal awareness. According to recurrent processing theory, early activity in primary sensory areas corresponds closely to phenomenal awareness. In support, research with electroencephalography found that in the visual and somatosensory modality, an early neural correlate of awareness is contralateral to the perceived side of stimulation. Thus, early activity is sensitive to the perceived side of visual and somatosensory stimulation. Critically, it is unresolved whether this is true also for hearing. In the present study (N = 26 students), Bayesian analyses showed that the early neural correlate of awareness (auditory awareness negativity, AAN) was stronger for contralateral than ipsilateral electrodes whereas the late correlate of auditory awareness (late positivity, LP) was not lateralized. These findings demonstrate that the early but not the late neural correlate of auditory awareness reflects lateralized experiences. Thus, these findings imply that AAN is a more suitable NCC than LP because it correlates more closely with lateralized experiences.
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Affiliation(s)
- Rasmus Eklund
- Gösta Ekmans Laboratorium, Stockholm University, Sweden.
| | | | - Stefan Wiens
- Gösta Ekmans Laboratorium, Stockholm University, Sweden
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Faramarzi M, Kasten FH, Altaş G, Aleman A, Ćurčić-Blake B, Herrmann CS. Similar EEG Activity Patterns During Experimentally-Induced Auditory Illusions and Veridical Perceptions. Front Neurosci 2021; 15:602437. [PMID: 33867913 PMCID: PMC8047478 DOI: 10.3389/fnins.2021.602437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 03/12/2021] [Indexed: 12/31/2022] Open
Abstract
Hallucinations and illusions are two instances of perceptual experiences illustrating how perception might diverge from external sensory stimulations and be generated or altered based on internal brain states. The occurrence of these phenomena is not constrained to patient populations. Similar experiences can be elicited in healthy subjects by means of suitable experimental procedures. Studying the neural mechanisms underlying these experiences not only has the potential to expand our understanding of the brain's perceptual machinery but also of how it might get impaired. In the current study, we employed an auditory signal detection task to induce auditory illusions by presenting speech snippets at near detection threshold intensity embedded in noise. We investigated the neural correlates of auditory false perceptions by examining the EEG activity preceding the responses in speech absent (false alarm, FA) trials and comparing them to speech present (hit) trials. The results of the comparison of event-related potentials (ERPs) in the activation period vs. baseline revealed the presence of an early negativity (EN) and a late positivity (LP) similar in both hits and FAs, which were absent in misses, correct rejections (CR) and control button presses (BPs). We postulate that the EN and the LP might represent the auditory awareness negativity (AAN) and centro-parietal positivity (CPP) or P300, respectively. The event-related spectral perturbations (ERSPs) exhibited a common power enhancement in low frequencies (<4 Hz) in hits and FAs. The low-frequency power enhancement has been frequently shown to be accompanied with P300 as well as separately being a marker of perceptual awareness, referred to as slow cortical potentials (SCP). Furthermore, the comparison of hits vs. FAs showed a significantly higher LP amplitude and low frequency power in hits compared to FAs. Generally, the observed patterns in the present results resembled some of the major neural correlates associated with perceptual awareness in previous studies. Our findings provide evidence that the neural correlates associated with conscious perception, can be elicited in similar ways in both presence and absence of externally presented sensory stimuli. The present findings did not reveal any pre-stimulus alpha and beta modulations distinguishing conscious vs. unconscious perceptions.
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Affiliation(s)
- Maryam Faramarzi
- Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster of Excellence “Hearing4All,” Carl von Ossietzky University, Oldenburg, Germany
- Department of Biomedical Sciences of Cells and Systems, Cognitive Neuroscience Center, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Florian H. Kasten
- Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster of Excellence “Hearing4All,” Carl von Ossietzky University, Oldenburg, Germany
- Neuroimaging Unit, European Medical School, Carl von Ossietzky University, Oldenburg, Germany
| | - Gamze Altaş
- Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster of Excellence “Hearing4All,” Carl von Ossietzky University, Oldenburg, Germany
| | - André Aleman
- Department of Biomedical Sciences of Cells and Systems, Cognitive Neuroscience Center, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Branislava Ćurčić-Blake
- Department of Biomedical Sciences of Cells and Systems, Cognitive Neuroscience Center, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Christoph S. Herrmann
- Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster of Excellence “Hearing4All,” Carl von Ossietzky University, Oldenburg, Germany
- Neuroimaging Unit, European Medical School, Carl von Ossietzky University, Oldenburg, Germany
- Research Center Neurosensory Science, Carl von Ossietzky University, Oldenburg, Germany
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