1
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Ludwig D. The functions of consciousness in visual processing. Neurosci Conscious 2023; 2023:niac018. [PMID: 36628118 PMCID: PMC9825248 DOI: 10.1093/nc/niac018] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/24/2022] [Accepted: 12/06/2022] [Indexed: 01/09/2023] Open
Abstract
Conscious experiences form a relatively diverse class of psychological phenomena, supported by a range of distinct neurobiological mechanisms. This diversity suggests that consciousness occupies a variety of different functional roles across different task domains, individuals, and species; a position I call functional pluralism. In this paper, I begin to tease out some of the functional contributions that consciousness makes to (human) visual processing. Consolidating research from across the cognitive sciences, I discuss semantic and spatiotemporal processing as specific points of comparison between the functional capabilities of the visual system in the presence and absence of conscious awareness. I argue that consciousness contributes a cluster of functions to visual processing; facilitating, among other things, (i) increased capacities for semantically processing informationally complex visual stimuli, (ii) increased spatiotemporal precision, and (iii) increased capacities for representational integration over large spatiotemporal intervals. This sort of analysis should ultimately yield a plurality of functional markers that can be used to guide future research in the philosophy and science of consciousness, some of which are not captured by popular theoretical frameworks like global workspace theory and information integration theory.
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Affiliation(s)
- Dylan Ludwig
- Department of Philosophy, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
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2
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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.
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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;
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3
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Liang XY, Guo ZH, Wang XD, Guo XT, Sun JW, Wang M, Li HW, Chen L. Event-Related Potential Evidence for Involuntary Consciousness During Implicit Memory Retrieval. Front Behav Neurosci 2022; 16:902175. [PMID: 35832295 PMCID: PMC9272755 DOI: 10.3389/fnbeh.2022.902175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/27/2022] [Indexed: 12/02/2022] Open
Abstract
Classical notion claims that a memory is implicit if has nothing to do with consciousness during the information retrieval from storage, or is otherwise explicit. Here, we demonstrate event-related potential evidence for involuntary consciousness during implicit memory retrieval. We designed a passive oddball paradigm for retrieval of implicit memory in which an auditory stream of Shepard tones with musical pitch interval contrasts were delivered to the subjects. These contrasts evoked a mismatch negativity response, which is an event-related potential and a neural marker of implicit memory, in the subjects with long-term musical training, but not in the subjects without. Notably, this response was followed by a salient P3 component which implies involvement of involuntary consciousness in the implicit memory retrieval. Finally, source analysis of the P3 revealed moving dipoles from the frontal lobe to the insula, a brain region closely related to conscious attention. Our study presents a case of involvement of involuntary consciousness in the implicit memory retrieval and suggests a potential challenge to the classical definition of implicit memory.
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Affiliation(s)
- Xiu-Yuan Liang
- Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Zi-Hao Guo
- Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Xiao-Dong Wang
- Faculty of Psychology, Southwest University, Chongqing, China
| | - Xiao-Tao Guo
- Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, University of Science and Technology of China, Hefei, China
| | - Jing-Wu Sun
- Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, University of Science and Technology of China, Hefei, China
| | - Ming Wang
- Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Hua-Wei Li
- Affiliated Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Lin Chen
- Auditory Research Laboratory, School of Life Sciences, University of Science and Technology of China, Hefei, China
- Affiliated Eye and ENT Hospital of Fudan University, Shanghai, China
- *Correspondence: Lin Chen,
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4
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Wu X, Zhao Y. Degree Centrality of a Brain Network Is Altered by Stereotype Threat: Evidences From a Resting-State Functional Magnetic Resonance Imaging Study. Front Psychol 2021; 12:705363. [PMID: 34531795 PMCID: PMC8439390 DOI: 10.3389/fpsyg.2021.705363] [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: 05/05/2021] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
Previous studies have found the effects of stereotype threat (ST) on cognitive processes, emotions, and motivations which could account for the underperformance in domain tasks. Efficient brain function does not require the function of different brain regions during specific tasks, but it does require the brain networks on which information is transported. Based on these, the effects of ST on the degree centrality under the resting state of brain regions related to these processes were investigated under math-related ST. The results showed that RSDC was decreased in the left hippocampus and left middle occipital gyrus (MOC), while RSDC was increased in the left precuneus, the right angular gyrus (AG), and the right superior parietal gyrus (SPG) under ST. Interestingly, we also found that the right-left anterior temporal lobe (ATL) and the right hippocampus were negatively correlated with manipulation check (MC) score in the ST group, while the right-left ATL and the right hippocampus were positively correlated with MC score in the control group. These results might reflect those individuals who attempted to inhibit the negative emotions induced by the negative stereotypes under ST conditions while increasing the self-relevant processes by retrieving episodic memory or autobiographical memory.
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Affiliation(s)
- Xin Wu
- Faculty of Psychology, Southwest University, Chongqing, China.,School of Psychology, Xinxiang Medical University, Xinxiang, China
| | - Yufang Zhao
- Faculty of Psychology, Southwest University, Chongqing, China
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5
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Levinson M, Podvalny E, Baete SH, He BJ. Cortical and subcortical signatures of conscious object recognition. Nat Commun 2021; 12:2930. [PMID: 34006884 PMCID: PMC8131711 DOI: 10.1038/s41467-021-23266-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/12/2021] [Indexed: 11/29/2022] Open
Abstract
The neural mechanisms underlying conscious recognition remain unclear, particularly the roles played by the prefrontal cortex, deactivated brain areas and subcortical regions. We investigated neural activity during conscious object recognition using 7 Tesla fMRI while human participants viewed object images presented at liminal contrasts. Here, we show both recognized and unrecognized images recruit widely distributed cortical and subcortical regions; however, recognized images elicit enhanced activation of visual, frontoparietal, and subcortical networks and stronger deactivation of the default-mode network. For recognized images, object category information can be decoded from all of the involved cortical networks but not from subcortical regions. Phase-scrambled images trigger strong involvement of inferior frontal junction, anterior cingulate cortex and default-mode network, implicating these regions in inferential processing under increased uncertainty. Our results indicate that content-specific activity in both activated and deactivated cortical networks and non-content-specific subcortical activity support conscious recognition. Cortical and subcortical neural activity supporting conscious object recognition has not yet been well defined. Here, the authors describe these networks and show recognition-related category information can be decoded from widespread cortical activity but not subcortical activity.
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Affiliation(s)
- Max Levinson
- Neuroscience Institute, New York University School of Medicine, New York, NY, USA
| | - Ella Podvalny
- Neuroscience Institute, New York University School of Medicine, New York, NY, USA
| | - Steven H Baete
- Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Biyu J He
- Neuroscience Institute, New York University School of Medicine, New York, NY, USA. .,Department of Radiology, New York University School of Medicine, New York, NY, USA. .,Department of Neurology, New York University School of Medicine, New York, NY, USA. .,Department of Neuroscience & Physiology, New York University School of Medicine, New York, NY, USA.
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6
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Hirschhorn R, Kahane O, Gur-Arie I, Faivre N, Mudrik L. Windows of Integration Hypothesis Revisited. Front Hum Neurosci 2021; 14:617187. [PMID: 33519404 PMCID: PMC7840615 DOI: 10.3389/fnhum.2020.617187] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/18/2020] [Indexed: 11/13/2022] Open
Abstract
In the ongoing research of the functions of consciousness, special emphasis has been put on integration of information: the ability to combine different signals into a coherent, unified one. Several theories of consciousness hold that this ability depends on - or at least goes hand in hand with - conscious processing. Yet some empirical findings have suggested otherwise, claiming that integration of information could take place even without awareness. Trying to reconcile this apparent contradiction, the "windows of integration" (WOI) hypothesis claims that conscious access enables signal processing over large integration windows. The hypothesis applies to integration windows defined either temporally, spatially, or semantically. In this review, we explain the hypothesis and re-examine it in light of new studies published since it was suggested. In line with the hypothesis, these studies provide compelling evidence for unconscious integration, but also demonstrate its limits with respect to time, space, and semantic distance. The review further highlights open questions that still need to be pursued to demonstrate the applicability of the WOI hypothesis as a guiding principle for understanding the depth and scope of unconscious processes.
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Affiliation(s)
- Rony Hirschhorn
- Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
| | - Ofer Kahane
- School of Psychological Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Inbal Gur-Arie
- School of Psychological Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Nathan Faivre
- Laboratoire de Psychologie et Neurocognition (LPNC), CNRS UMR 5105, Université Grenoble Alpes, Grenoble, France
| | - Liad Mudrik
- Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
- School of Psychological Sciences, Tel-Aviv University, Tel-Aviv, Israel
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7
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Fedorenko E, Blank IA, Siegelman M, Mineroff Z. Lack of selectivity for syntax relative to word meanings throughout the language network. Cognition 2020; 203:104348. [PMID: 32569894 DOI: 10.1101/477851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 05/14/2020] [Accepted: 05/31/2020] [Indexed: 05/25/2023]
Abstract
To understand what you are reading now, your mind retrieves the meanings of words and constructions from a linguistic knowledge store (lexico-semantic processing) and identifies the relationships among them to construct a complex meaning (syntactic or combinatorial processing). Do these two sets of processes rely on distinct, specialized mechanisms or, rather, share a common pool of resources? Linguistic theorizing, empirical evidence from language acquisition and processing, and computational modeling have jointly painted a picture whereby lexico-semantic and syntactic processing are deeply inter-connected and perhaps not separable. In contrast, many current proposals of the neural architecture of language continue to endorse a view whereby certain brain regions selectively support syntactic/combinatorial processing, although the locus of such "syntactic hub", and its nature, vary across proposals. Here, we searched for selectivity for syntactic over lexico-semantic processing using a powerful individual-subjects fMRI approach across three sentence comprehension paradigms that have been used in prior work to argue for such selectivity: responses to lexico-semantic vs. morpho-syntactic violations (Experiment 1); recovery from neural suppression across pairs of sentences differing in only lexical items vs. only syntactic structure (Experiment 2); and same/different meaning judgments on such sentence pairs (Experiment 3). Across experiments, both lexico-semantic and syntactic conditions elicited robust responses throughout the left fronto-temporal language network. Critically, however, no regions were more strongly engaged by syntactic than lexico-semantic processing, although some regions showed the opposite pattern. Thus, contra many current proposals of the neural architecture of language, syntactic/combinatorial processing is not separable from lexico-semantic processing at the level of brain regions-or even voxel subsets-within the language network, in line with strong integration between these two processes that has been consistently observed in behavioral and computational language research. The results further suggest that the language network may be generally more strongly concerned with meaning than syntactic form, in line with the primary function of language-to share meanings across minds.
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Affiliation(s)
- Evelina Fedorenko
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; McGovern Institute for Brain Research, MIT, Cambridge, MA 02139, USA.
| | - Idan Asher Blank
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; Department of Psychology, UCLA, Los Angeles, CA 90095, USA
| | - Matthew Siegelman
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; Department of Psychology, Columbia University, New York, NY 10027, USA
| | - Zachary Mineroff
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; Eberly Center for Teaching Excellence & Educational Innovation, CMU, Pittsburgh, PA 15213, USA
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8
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Marron TR, Berant E, Axelrod V, Faust M. Spontaneous cognition and its relationship to human creativity: A functional connectivity study involving a chain free association task. Neuroimage 2020; 220:117064. [DOI: 10.1016/j.neuroimage.2020.117064] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 05/24/2020] [Accepted: 06/13/2020] [Indexed: 11/30/2022] Open
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9
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Fedorenko E, Blank IA, Siegelman M, Mineroff Z. Lack of selectivity for syntax relative to word meanings throughout the language network. Cognition 2020; 203:104348. [PMID: 32569894 PMCID: PMC7483589 DOI: 10.1016/j.cognition.2020.104348] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 05/14/2020] [Accepted: 05/31/2020] [Indexed: 12/31/2022]
Abstract
To understand what you are reading now, your mind retrieves the meanings of words and constructions from a linguistic knowledge store (lexico-semantic processing) and identifies the relationships among them to construct a complex meaning (syntactic or combinatorial processing). Do these two sets of processes rely on distinct, specialized mechanisms or, rather, share a common pool of resources? Linguistic theorizing, empirical evidence from language acquisition and processing, and computational modeling have jointly painted a picture whereby lexico-semantic and syntactic processing are deeply inter-connected and perhaps not separable. In contrast, many current proposals of the neural architecture of language continue to endorse a view whereby certain brain regions selectively support syntactic/combinatorial processing, although the locus of such "syntactic hub", and its nature, vary across proposals. Here, we searched for selectivity for syntactic over lexico-semantic processing using a powerful individual-subjects fMRI approach across three sentence comprehension paradigms that have been used in prior work to argue for such selectivity: responses to lexico-semantic vs. morpho-syntactic violations (Experiment 1); recovery from neural suppression across pairs of sentences differing in only lexical items vs. only syntactic structure (Experiment 2); and same/different meaning judgments on such sentence pairs (Experiment 3). Across experiments, both lexico-semantic and syntactic conditions elicited robust responses throughout the left fronto-temporal language network. Critically, however, no regions were more strongly engaged by syntactic than lexico-semantic processing, although some regions showed the opposite pattern. Thus, contra many current proposals of the neural architecture of language, syntactic/combinatorial processing is not separable from lexico-semantic processing at the level of brain regions-or even voxel subsets-within the language network, in line with strong integration between these two processes that has been consistently observed in behavioral and computational language research. The results further suggest that the language network may be generally more strongly concerned with meaning than syntactic form, in line with the primary function of language-to share meanings across minds.
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Affiliation(s)
- Evelina Fedorenko
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; McGovern Institute for Brain Research, MIT, Cambridge, MA 02139, USA.
| | - Idan Asher Blank
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; Department of Psychology, UCLA, Los Angeles, CA 90095, USA
| | - Matthew Siegelman
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; Department of Psychology, Columbia University, New York, NY 10027, USA
| | - Zachary Mineroff
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA; Eberly Center for Teaching Excellence & Educational Innovation, CMU, Pittsburgh, PA 15213, USA
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10
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Ngetich R, Zhou J, Zhang J, Jin Z, Li L. Assessing the Effects of Continuous Theta Burst Stimulation Over the Dorsolateral Prefrontal Cortex on Human Cognition: A Systematic Review. Front Integr Neurosci 2020; 14:35. [PMID: 32848648 PMCID: PMC7417340 DOI: 10.3389/fnint.2020.00035] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 06/03/2020] [Indexed: 01/11/2023] Open
Abstract
Theta burst stimulation is increasingly growing in popularity as a non-invasive method of moderating corticospinal networks. Theta burst stimulation uses gamma frequency trains applied at the rhythm of theta, thus, mimicking theta–gamma coupling involved in cognitive processes. The dorsolateral prefrontal cortex has been found to play a crucial role in numerous cognitive processes. Here, we include 25 studies for review to determine the cognitive effects of continuous theta burst stimulation over the dorsolateral prefrontal cortex; 20 of these studies are healthy participant and five are patient (pharmacotherapy-resistant depression) studies. Due to the heterogeneous nature of the included studies, only a descriptive approach is used and meta-analytics ruled out. The cognitive effect is measured on various cognitive domains: attention, working memory, planning, language, decision making, executive function, and inhibitory and cognitive control. We conclude that continuous theta burst stimulation over the dorsolateral prefrontal cortex mainly inhibits cognitive performance. However, in some instances, it can lead to improved performance by inhibiting the effect of distractors or other competing irrelevant cognitive processes. To be precise, continuous theta burst stimulation over the right dorsolateral prefrontal cortex impaired attention, inhibitory control, planning, and goal-directed behavior in decision making but also improved decision making by reducing impulsivity. Conversely, continuous theta burst stimulation over the left dorsolateral prefrontal cortex impaired executive function, working, auditory feedback regulation, and cognitive control but accelerated the planning, decision-making process. These findings constitute a useful contribution to the literature on the cognitive effects of continuous theta burst stimulation over the dorsolateral prefrontal cortex.
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Affiliation(s)
- Ronald Ngetich
- Key Laboratory for Neuroinformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Jing Zhou
- Key Laboratory for Neuroinformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Junjun Zhang
- Key Laboratory for Neuroinformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Zhenlan Jin
- Key Laboratory for Neuroinformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Ling Li
- Key Laboratory for Neuroinformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
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11
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No language unification without neural feedback: How awareness affects sentence processing. Neuroimage 2019; 202:116063. [PMID: 31376519 DOI: 10.1016/j.neuroimage.2019.116063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/22/2019] [Accepted: 07/30/2019] [Indexed: 01/08/2023] Open
Abstract
How does the human brain combine a finite number of words to form an infinite variety of sentences? According to the Memory, Unification and Control (MUC) model, sentence processing requires long-range feedback from the left inferior frontal cortex (LIFC) to left posterior temporal cortex (LPTC). Single word processing however may only require feedforward propagation of semantic information from sensory regions to LPTC. Here we tested the claim that long-range feedback is required for sentence processing by reducing visual awareness of words using a masking technique. Masking disrupts feedback processing while leaving feedforward processing relatively intact. Previous studies have shown that masked single words still elicit an N400 ERP effect, a neural signature of semantic incongruency. However, whether multiple words can be combined to form a sentence under reduced levels of awareness is controversial. To investigate this issue, we performed two experiments in which we measured electroencephalography (EEG) while 40 subjects performed a masked priming task. Words were presented either successively or simultaneously, thereby forming a short sentence that could be congruent or incongruent with a target picture. This sentence condition was compared with a typical single word condition. In the masked condition we only found an N400 effect for single words, whereas in the unmasked condition we observed an N400 effect for both unmasked sentences and single words. Our findings suggest that long-range feedback processing is required for sentence processing, but not for single word processing.
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12
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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
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13
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Soto D, Sheikh UA, Rosenthal CR. A Novel Framework for Unconscious Processing. Trends Cogn Sci 2019; 23:372-376. [PMID: 30981588 DOI: 10.1016/j.tics.2019.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 02/28/2019] [Accepted: 03/04/2019] [Indexed: 01/22/2023]
Abstract
Understanding the distinction between conscious and unconscious cognition remains a priority in psychology and neuroscience. A comprehensive neurocognitive account of conscious awareness will not be possible without a sound framework to isolate and understand unconscious information processing. Here, we provide a brain-based framework that allows the identification of unconscious processes, even with null effects on behaviour.
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Affiliation(s)
- David Soto
- Basque Center on Cognition, Brain and Language, San Sebastián, Spain; Ikerbasque, Basque Foundation for Science, Bilbao, Spain.
| | - Usman Ayub Sheikh
- Basque Center on Cognition, Brain and Language, San Sebastián, Spain
| | - Clive R Rosenthal
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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14
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Zhou Z, Whitney C, Strother L. Embedded word priming elicits enhanced fMRI responses in the visual word form area. PLoS One 2019; 14:e0208318. [PMID: 30629612 PMCID: PMC6328158 DOI: 10.1371/journal.pone.0208318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 11/15/2018] [Indexed: 11/19/2022] Open
Abstract
Lexical embedding is common in all languages and elicits mutual orthographic interference between an embedded word and its carrier. The neural basis of such interference remains unknown. We employed a novel fMRI prime-target embedded word paradigm to test for involvement of a visual word form area (VWFA) in left ventral occipitotemporal cortex in co-activation of embedded words and their carriers. Based on the results of related fMRI studies we predicted either enhancement or suppression of fMRI responses to embedded words initially viewed as primes, and repeated in the context of target carrier words. Our results clearly showed enhancement of fMRI responses in the VWFA to embedded-carrier word pairs as compared to unrelated prime-target pairs. In contrast to non-visual language-related areas (e.g., left inferior frontal gyrus), enhanced fMRI responses did not occur in the VWFA when embedded-carrier word pairs were restricted to the left visual hemifield. Our finding of fMRI enhancement in the VWFA is novel evidence of its involvement in representational rivalry between orthographically similar words, and the co-activation of embedded words and their carriers.
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Affiliation(s)
- Zhiheng Zhou
- Department of Psychology, University of Nevada, Reno, NV, United States of America
| | - Carol Whitney
- Independent Researcher, Silver Spring, MD, United States of America
| | - Lars Strother
- Department of Psychology, University of Nevada, Reno, NV, United States of America
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15
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Oxner M, Corballis PM, Hayward WG. The relation of discrete stimuli can be integrated despite the failure of conscious identification. VISUAL COGNITION 2018. [DOI: 10.1080/13506285.2018.1541035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Matt Oxner
- School of Psychology, University of Auckland, Auckland, New Zealand
| | | | - William G. Hayward
- School of Psychology, University of Auckland, Auckland, New Zealand
- Department of Psychology and ARC Centre of Excellence in Cognition and Its Disorders, The University of Hong Kong, Pokfulam Road, Hong Kong
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16
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Bhandari A, Gagne C, Badre D. Just above Chance: Is It Harder to Decode Information from Prefrontal Cortex Hemodynamic Activity Patterns? J Cogn Neurosci 2018; 30:1473-1498. [PMID: 29877764 DOI: 10.1162/jocn_a_01291] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The prefrontal cortex (PFC) is central to flexible, goal-directed cognition, and understanding its representational code is an important problem in cognitive neuroscience. In humans, multivariate pattern analysis (MVPA) of fMRI blood oxygenation level-dependent (BOLD) measurements has emerged as an important approach for studying neural representations. Many previous studies have implicitly assumed that MVPA of fMRI BOLD is just as effective in decoding information encoded in PFC neural activity as it is in visual cortex. However, MVPA studies of PFC have had mixed success. Here we estimate the base rate of decoding information from PFC BOLD activity patterns from a meta-analysis of published MVPA studies. We show that PFC has a significantly lower base rate (55.4%) than visual areas in occipital (66.6%) and temporal (71.0%) cortices and one that is close to chance levels. Our results have implications for the design and interpretation of MVPA studies of PFC and raise important questions about its functional organization.
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Affiliation(s)
| | | | - David Badre
- Brown University.,Carney Institute for Brain Science, Providence, RI
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17
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Nakamura K, Makuuchi M, Oga T, Mizuochi-Endo T, Iwabuchi T, Nakajima Y, Dehaene S. Neural capacity limits during unconscious semantic processing. Eur J Neurosci 2018. [DOI: 10.1111/ejn.13890] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kimihiro Nakamura
- Faculty of Human Sciences; University of Tsukuba; Tsukuba 305-8577 Japan
| | - Michiru Makuuchi
- National Rehabilitation Center for Persons with Disabilities; Tokorozawa 359-0042 Japan
| | - Tatsuhide Oga
- Toranomon Hospital Kajigaya; Kawasaki 213-0015 Japan
| | - Tomomi Mizuochi-Endo
- National Rehabilitation Center for Persons with Disabilities; Tokorozawa 359-0042 Japan
| | - Toshiki Iwabuchi
- National Rehabilitation Center for Persons with Disabilities; Tokorozawa 359-0042 Japan
| | - Yasoichi Nakajima
- National Rehabilitation Center for Persons with Disabilities; Tokorozawa 359-0042 Japan
| | - Stanislas Dehaene
- Cognitive Neuroimaging Unit; CEA DSV/I2BM; INSERM; NeuroSpin Center; Université Paris-Sud; Université Paris-Saclay; 91191 Gif/Yvette France
- Collège de France; 11 Place Marcelin Berthelot 75005 Paris France
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18
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Meijboom R, Steketee RME, Ham LS, van der Lugt A, van Swieten JC, Smits M. Differential Hemispheric Predilection of Microstructural White Matter and Functional Connectivity Abnormalities between Respectively Semantic and Behavioral Variant Frontotemporal Dementia. J Alzheimers Dis 2018; 56:789-804. [PMID: 28059782 DOI: 10.3233/jad-160564] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Semantic dementia (SD) and behavioral variant frontotemporal dementia (bvFTD), subtypes of frontotemporal dementia, are characterized by distinct clinical symptoms and neuroimaging features, with predominant left temporal grey matter (GM) atrophy in SD and bilateral or right frontal GM atrophy in bvFTD. Such differential hemispheric predilection may also be reflected by other neuroimaging features, such as brain connectivity. This study investigated white matter (WM) microstructure and functional connectivity differences between SD and bvFTD, focusing on the hemispheric predilection of these differences. Eight SD and 12 bvFTD patients, and 17 controls underwent diffusion tensor imaging and resting state functional MRI at 3T. Whole-brain WM microstructure was assessed to determine distinct WM tracts affected in SD and bvFTD. For these tracts, diffusivity measures and lateralization indices were calculated. Functional connectivity was established for GM regions affected in early stage SD or bvFTD. Results of a direct comparison between SD and bvFTD are reported. Whole-brain WM microstructure abnormalities were more pronounced in the left hemisphere in SD and bilaterally- with a slight predilection for the right- in bvFTD. Lateralization of tract-specific abnormalities was seen in SD only, toward the left hemisphere. Functional connectivity of disease-specific regions was mainly decreased bilaterally in SD and in the right hemisphere in bvFTD. SD and bvFTD show WM microstructure and functional connectivity abnormalities in different regions, that are respectively more pronounced in the left hemisphere in SD and in the right hemisphere in bvFTD. This indicates differential hemispheric predilection of brain connectivity abnormalities between SD and bvFTD.
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Affiliation(s)
- Rozanna Meijboom
- Department of Radiology and Nuclear Medicine, Erasmus MC - University Medical Centre Rotterdam, The Netherlands
| | - Rebecca M E Steketee
- Department of Radiology and Nuclear Medicine, Erasmus MC - University Medical Centre Rotterdam, The Netherlands
| | - Leontine S Ham
- Department of Radiology and Nuclear Medicine, Erasmus MC - University Medical Centre Rotterdam, The Netherlands
| | - Aad van der Lugt
- Department of Radiology and Nuclear Medicine, Erasmus MC - University Medical Centre Rotterdam, The Netherlands
| | - John C van Swieten
- Department of Neurology, Erasmus MC - University Medical Centre Rotterdam, The Netherlands
| | - Marion Smits
- Department of Radiology and Nuclear Medicine, Erasmus MC - University Medical Centre Rotterdam, The Netherlands
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19
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Axelrod V, Rees G, Bar M. The default network and the combination of cognitive processes that mediate self-generated thought. Nat Hum Behav 2017; 1:896-910. [PMID: 30035236 DOI: 10.1038/s41562-017-0244-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Self-generated cognitions, such as recalling personal memories or empathizing with others, are ubiquitous and essential for our lives. Such internal mental processing is ascribed to the Default Mode Network, a large network of the human brain, though the underlying neural and cognitive mechanisms remain poorly understood. Here, we tested the hypothesis that our mental experience is mediated by a combination of activities of multiple cognitive processes. Our study included four functional MRI experiments with the same participants and a wide range of cognitive tasks, as well as an analytical approach that afforded the identification of cognitive processes during self-generated cognition. We showed that several cognitive processes functioned simultaneously during self-generated mental activity. The processes had specific and localized neural representations, suggesting that they support different aspects of internal processing. Overall, we demonstrate that internally directed experience may be achieved by pooling over multiple cognitive processes.
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Affiliation(s)
- Vadim Axelrod
- Gonda Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, Israel. .,Institute of Cognitive Neuroscience, University College London, London, UK.
| | - Geraint Rees
- Institute of Cognitive Neuroscience, University College London, London, UK.,Wellcome Trust Centre for Neuroimaging, University College London, London, UK
| | - Moshe Bar
- Gonda Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, Israel
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20
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Blank IA, Kiran S, Fedorenko E. Can neuroimaging help aphasia researchers? Addressing generalizability, variability, and interpretability. Cogn Neuropsychol 2017; 34:377-393. [PMID: 29188746 PMCID: PMC6157596 DOI: 10.1080/02643294.2017.1402756] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Neuroimaging studies of individuals with brain damage seek to link brain structure and activity to cognitive impairments, spontaneous recovery, or treatment outcomes. To date, such studies have relied on the critical assumption that a given anatomical landmark corresponds to the same functional unit(s) across individuals. However, this assumption is fallacious even across neurologically healthy individuals. Here, we discuss the severe implications of this issue, and argue for an approach that circumvents it, whereby: (i) functional brain regions are defined separately for each subject using fMRI, allowing for inter-individual variability in their precise location; (ii) the response profile of these subject-specific regions are characterized using various other tasks; and (iii) the results are averaged across individuals, guaranteeing generalizabliity. This method harnesses the complementary strengths of single-case studies and group studies, and it eliminates the need for post hoc "reverse inference" from anatomical landmarks back to cognitive operations, thus improving data interpretability.
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Affiliation(s)
- Idan A Blank
- a McGovern Institute for Brain Research , Massachusetts Institute of Technology , Cambridge , MA , USA
| | - Swathi Kiran
- b Department of Speech Language and Hearing Sciences, Aphasia Research Laboratory , Sargent College, Boston University , Boston , MA , USA
| | - Evelina Fedorenko
- c Department of Psychiatry , Massachusetts General Hospital , Charlestown , MA , USA
- d Department of Psychiatry , Harvard Medical School , Boston , MA , USA
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21
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ERP signatures of conscious and unconscious word and letter perception in an inattentional blindness paradigm. Conscious Cogn 2017; 54:56-71. [DOI: 10.1016/j.concog.2017.04.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 03/23/2017] [Accepted: 04/14/2017] [Indexed: 01/01/2023]
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22
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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
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23
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Navajas J, Nitka AW, Quian Quiroga R. Dissociation between the neural correlates of conscious face perception and visual attention. Psychophysiology 2017; 54:1138-1150. [DOI: 10.1111/psyp.12873] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/12/2017] [Accepted: 03/10/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Joaquin Navajas
- Centre for Systems Neuroscience, University of Leicester; Leicester United Kingdom
- Institute of Cognitive Neuroscience, University College London; London United Kingdom
| | - Aleksander W. Nitka
- Centre for Systems Neuroscience, University of Leicester; Leicester United Kingdom
- School of Psychology; University of Leicester; Leicester United Kingdom
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24
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Lei Y, Dou H, Liu Q, Zhang W, Zhang Z, Li H. Automatic Processing of Emotional Words in the Absence of Awareness: The Critical Role of P2. Front Psychol 2017; 8:592. [PMID: 28473785 PMCID: PMC5397533 DOI: 10.3389/fpsyg.2017.00592] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 03/30/2017] [Indexed: 01/22/2023] Open
Abstract
It has been long debated to what extent emotional words can be processed in the absence of awareness. Behavioral studies have shown that the meaning of emotional words can be accessed even without any awareness. However, functional magnetic resonance imaging studies have revealed that emotional words that are unconsciously presented do not activate the brain regions involved in semantic or emotional processing. To clarify this point, we used continuous flash suppression (CFS) and event-related potential (ERP) techniques to distinguish between semantic and emotional processing. In CFS, we successively flashed some Mondrian-style images into one participant's eye steadily, which suppressed the images projected to the other eye. Negative, neutral, and scrambled words were presented to 16 healthy participants for 500 ms. Whenever the participants saw the stimuli—in both visible and invisible conditions—they pressed specific keyboard buttons. Behavioral data revealed that there was no difference in reaction time to negative words and to neutral words in the invisible condition, although negative words were processed faster than neutral words in the visible condition. The ERP results showed that negative words elicited a larger P2 amplitude in the invisible condition than in the visible condition. The P2 component was enhanced for the neutral words compared with the scrambled words in the visible condition; however, the scrambled words elicited larger P2 amplitudes than the neutral words in the invisible condition. These results suggest that the emotional processing of words is more sensitive than semantic processing in the conscious condition. Semantic processing was found to be attenuated in the absence of awareness. Our findings indicate that P2 plays an important role in the unconscious processing of emotional words, which highlights the fact that emotional processing may be automatic and prioritized compared with semantic processing in the absence of awareness.
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Affiliation(s)
- Yi Lei
- College of Psychology and Sociology, Shenzhen UniversityShenzhen, China
| | - Haoran Dou
- College of Psychology and Sociology, Shenzhen UniversityShenzhen, China.,Research Center for Brain and Cognitive Neuroscience, Liaoning Normal UniversityDalian, China
| | - Qingming Liu
- School of Psychology, Nanjing Normal UniversityNanjing, China
| | - Wenhai Zhang
- Research Center for Brain and Cognitive Neuroscience, Liaoning Normal UniversityDalian, China.,College of Education Science, Chengdu UniversityChengdu, China
| | - Zhonglu Zhang
- Research Center for Brain and Cognitive Neuroscience, Liaoning Normal UniversityDalian, China
| | - Hong Li
- College of Psychology and Sociology, Shenzhen UniversityShenzhen, China.,Research Center for Brain and Cognitive Neuroscience, Liaoning Normal UniversityDalian, China.,College of Education Science, Chengdu UniversityChengdu, China
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25
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Scott TL, Gallée J, Fedorenko E. A new fun and robust version of an fMRI localizer for the frontotemporal language system. Cogn Neurosci 2016; 8:167-176. [PMID: 27386919 DOI: 10.1080/17588928.2016.1201466] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A set of brain regions in the frontal, temporal, and parietal lobes supports high-level linguistic processing. These regions can be reliably identified in individual subjects using fMRI, by contrasting neural responses to meaningful and structured language stimuli vs. stimuli matched for low-level properties but lacking meaning and/or structure. We here present a novel version of a language 'localizer,' which should be suitable for diverse populations including children and/or clinical populations who may have difficulty with reading or cognitively demanding tasks. In particular, we contrast responses to auditorily presented excerpts from engaging interviews or stories, and acoustically degraded versions of these materials. This language localizer is appealing because it uses (a) naturalistic and engaging linguistic materials, (b) auditory presentation,
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Affiliation(s)
- Terri L Scott
- a Boston University , Graduate Program for Neuroscience , Boston , MA , USA
| | - Jeanne Gallée
- b Department of Cognitive and Linguistic Sciences , Wellesley College , Wellesley , MA , USA
| | - Evelina Fedorenko
- c Massachusetts General Hospital , Harvard Medical School, Department of Psychiatry, Athinoula A. Martinos Center for Biomedical Imaging , Charlestown , MA , USA.,d Massachusetts Institute of Technology , McGovern Institute for Brain Research , Cambridge , MA , USA
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26
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Axelrod V. On the domain-specificity of the visual and non-visual face-selective regions. Eur J Neurosci 2016; 44:2049-63. [PMID: 27255921 DOI: 10.1111/ejn.13290] [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: 06/15/2015] [Revised: 05/21/2016] [Accepted: 05/24/2016] [Indexed: 11/27/2022]
Abstract
What happens in our brains when we see a face? The neural mechanisms of face processing - namely, the face-selective regions - have been extensively explored. Research has traditionally focused on visual cortex face-regions; more recently, the role of face-regions outside the visual cortex (i.e., non-visual-cortex face-regions) has been acknowledged as well. The major quest today is to reveal the functional role of each this region in face processing. To make progress in this direction, it is essential to understand the extent to which the face-regions, and particularly the non-visual-cortex face-regions, process only faces (i.e., face-specific, domain-specific processing) or rather are involved in a more domain-general cognitive processing. In the current functional MRI study, we systematically examined the activity of the whole face-network during face-unrelated reading task (i.e., written meaningful sentences with content unrelated to faces/people and non-words). We found that the non-visual-cortex (i.e., right lateral prefrontal cortex and posterior superior temporal sulcus), but not the visual cortex face-regions, responded significantly stronger to sentences than to non-words. In general, some degree of sentence selectivity was found in all non-visual-cortex cortex. Present result highlights the possibility that the processing in the non-visual-cortex face-selective regions might not be exclusively face-specific, but rather more or even fully domain-general. In this paper, we illustrate how the knowledge about domain-general processing in face-regions can help to advance our general understanding of face processing mechanisms. Our results therefore suggest that the problem of face processing should be approached in the broader scope of cognition in general.
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Affiliation(s)
- Vadim Axelrod
- UCL Institute of Cognitive Neuroscience, University College London, London, UK.,The Gonda Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, 52900, Israel
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27
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The relationships between the amount of spared tissue, percent signal change, and accuracy in semantic processing in aphasia. Neuropsychologia 2016; 84:113-26. [PMID: 26775192 DOI: 10.1016/j.neuropsychologia.2015.10.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 09/10/2015] [Accepted: 10/12/2015] [Indexed: 12/31/2022]
Abstract
Recovery from aphasia, loss of language following a cerebrovascular incident (stroke), is a complex process involving both left and right hemispheric regions. In our study, we analyzed the relationships between semantic processing behavioral data, lesion size and location, and percent signal change from functional magnetic resonance imaging (fMRI) data. This study included 14 persons with aphasia in the chronic stage of recovery (six or more months post stroke), along with normal controls, who performed semantic processing tasks of determining whether a written semantic feature matched a picture or whether two written words were related. Using region of interest (ROI) analysis, we found that left inferior frontal gyrus pars opercularis and pars triangularis, despite significant damage, were the only regions to correlate with behavioral accuracy. Additionally, bilateral frontal regions including superior frontal gyrus, middle frontal gyrus, and anterior cingulate appear to serve as an assistive network in the case of damage to traditional language regions that include inferior frontal gyrus, middle temporal gyrus, supramarginal gyrus, and angular gyrus. Right hemisphere posterior regions including right middle temporal gyrus, right supramarginal gyrus, and right angular gyrus are engaged in the case of extensive damage to left hemisphere language regions. Additionally, right inferior frontal gyrus pars orbitalis is presumed to serve a monitoring function. These results reinforce the importance of the left hemisphere in language processing in aphasia, and provide a framework for the relative importance of left and right language regions in the brain.
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28
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Stimulus-driven changes in the direction of neural priming during visual word recognition. Neuroimage 2015; 125:428-436. [PMID: 26514294 DOI: 10.1016/j.neuroimage.2015.10.063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/22/2015] [Accepted: 10/03/2015] [Indexed: 11/24/2022] Open
Abstract
Visual object recognition is generally known to be facilitated when targets are preceded by the same or relevant stimuli. For written words, however, the beneficial effect of priming can be reversed when primes and targets share initial syllables (e.g., "boca" and "bono"). Using fMRI, the present study explored neuroanatomical correlates of this negative syllabic priming. In each trial, participants made semantic judgment about a centrally presented target, which was preceded by a masked prime flashed either to the left or right visual field. We observed that the inhibitory priming during reading was associated with a left-lateralized effect of repetition enhancement in the inferior frontal gyrus (IFG), rather than repetition suppression in the ventral visual region previously associated with facilitatory behavioral priming. We further performed a second fMRI experiment using a classical whole-word repetition priming paradigm with the same hemifield procedure and task instruction, and obtained well-known effects of repetition suppression in the left occipito-temporal cortex. These results therefore suggest that the left IFG constitutes a fast word processing system distinct from the posterior visual word-form system and that the directions of repetition effects can change with intrinsic properties of stimuli even when participants' cognitive and attentional states are kept constant.
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29
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Axelrod V, Yovel G. Successful decoding of famous faces in the fusiform face area. PLoS One 2015; 10:e0117126. [PMID: 25714434 PMCID: PMC4340964 DOI: 10.1371/journal.pone.0117126] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 12/19/2014] [Indexed: 11/18/2022] Open
Abstract
What are the neural mechanisms of face recognition? It is believed that the network of face-selective areas, which spans the occipital, temporal, and frontal cortices, is important in face recognition. A number of previous studies indeed reported that face identity could be discriminated based on patterns of multivoxel activity in the fusiform face area and the anterior temporal lobe. However, given the difficulty in localizing the face-selective area in the anterior temporal lobe, its role in face recognition is still unknown. Furthermore, previous studies limited their analysis to occipito-temporal regions without testing identity decoding in more anterior face-selective regions, such as the amygdala and prefrontal cortex. In the current high-resolution functional Magnetic Resonance Imaging study, we systematically examined the decoding of the identity of famous faces in the temporo-frontal network of face-selective and adjacent non-face-selective regions. A special focus has been put on the face-area in the anterior temporal lobe, which was reliably localized using an optimized scanning protocol. We found that face-identity could be discriminated above chance level only in the fusiform face area. Our results corroborate the role of the fusiform face area in face recognition. Future studies are needed to further explore the role of the more recently discovered anterior face-selective areas in face recognition.
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Affiliation(s)
- Vadim Axelrod
- School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Galit Yovel
- School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel; School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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30
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Schmid MC, Maier A. To see or not to see--thalamo-cortical networks during blindsight and perceptual suppression. Prog Neurobiol 2015; 126:36-48. [PMID: 25661166 DOI: 10.1016/j.pneurobio.2015.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 01/05/2015] [Accepted: 01/14/2015] [Indexed: 11/15/2022]
Abstract
Even during moments when we fail to be fully aware of our environment, our brains never go silent. Instead, it appears that the brain can also operate in an alternate, unconscious mode. Delineating unconscious from conscious neural processes is a promising first step toward investigating how awareness emerges from brain activity. Here we focus on recent insights into the neuronal processes that contribute to visual function in the absence of a conscious visual percept. Drawing on insights from findings on the phenomenon of blindsight that results from injury to primary visual cortex and the results of experimentally induced perceptual suppression, we describe what kind of visual information the visual system analyzes unconsciously and we discuss the neuronal routing and responses that accompany this process. We conclude that unconscious processing of certain visual stimulus attributes, such as the presence of visual motion or the emotional expression of a face can occur in a geniculo-cortical circuit that runs independent from and in parallel to the predominant route through primary visual cortex. We speculate that in contrast, bidirectional neuronal interactions between cortex and the thalamic pulvinar nucleus that support large-scale neuronal integration and visual awareness are impeded during blindsight and perceptual suppression.
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Affiliation(s)
- Michael C Schmid
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Deutschordenstraße 46, Frankfurt a. M. 60528, Germany.
| | - Alexander Maier
- Vanderbilt University, Department of Psychology, 111 21st Avenue South, 301 Wilson Hall, Nashville, TN 37240, USA.
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31
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Axelrod V, Bar M, Rees G. Exploring the unconscious using faces. Trends Cogn Sci 2015; 19:35-45. [DOI: 10.1016/j.tics.2014.11.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 10/17/2014] [Accepted: 11/03/2014] [Indexed: 12/12/2022]
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32
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Axelrod V. Minimizing bugs in cognitive neuroscience programming. Front Psychol 2014; 5:1435. [PMID: 25566120 PMCID: PMC4269119 DOI: 10.3389/fpsyg.2014.01435] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 11/24/2014] [Indexed: 11/30/2022] Open
Affiliation(s)
- Vadim Axelrod
- The Gonda Multidisciplinary Brain Research Center, Bar Ilan University Ramat Gan, Israel ; Institute of Cognitive Neuroscience, University College London London, UK
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33
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Iijima K, Sakai KL. Subliminal enhancement of predictive effects during syntactic processing in the left inferior frontal gyrus: an MEG study. Front Syst Neurosci 2014; 8:217. [PMID: 25404899 PMCID: PMC4217366 DOI: 10.3389/fnsys.2014.00217] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 10/13/2014] [Indexed: 11/16/2022] Open
Abstract
Predictive syntactic processing plays an essential role in language comprehension. In our previous study using Japanese object-verb (OV) sentences, we showed that the left inferior frontal gyrus (IFG) responses to a verb increased at 120-140 ms after the verb onset, indicating predictive effects caused by a preceding object. To further elucidate the automaticity of the predictive effects in the present magnetoencephalography study, we examined whether a subliminally presented verb ("subliminal verb") enhanced the predictive effects on the sentence-final verb ("target verb") unconsciously, i.e., without awareness. By presenting a subliminal verb after the object, enhanced predictive effects on the target verb would be detected in the OV sentences when the transitivity of the target verb matched with that of the subliminal verb ("congruent condition"), because the subliminal verb just after the object could determine the grammaticality of the sentence. For the OV sentences under the congruent condition, we observed significantly increased left IFG responses at 140-160 ms after the target verb onset. In contrast, responses in the precuneus and midcingulate cortex (MCC) were significantly reduced for the OV sentences under the congruent condition at 110-140 and 280-300 ms, respectively. By using partial Granger causality analyses for the OV sentences under the congruent condition, we revealed a bidirectional interaction between the left IFG and MCC at 60-160 ms, as well as a significant influence from the MCC to the precuneus. These results indicate that a top-down influence from the left IFG to the MCC, and then to the precuneus, is critical in syntactic decisions, whereas the MCC shares its task-set information with the left IFG to achieve automatic and predictive processes of syntax.
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Affiliation(s)
- Kazuki Iijima
- Department of Basic Science, Graduate School of Arts and Sciences, The University of TokyoMeguro-ku, Japan
- CREST, Japan Science and Technology AgencyChiyoda-ku, Japan
- Japan Society for the Promotion of ScienceChiyoda-ku, Japan
| | - Kuniyoshi L. Sakai
- Department of Basic Science, Graduate School of Arts and Sciences, The University of TokyoMeguro-ku, Japan
- CREST, Japan Science and Technology AgencyChiyoda-ku, Japan
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34
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Navajas J, Rey HG, Quian Quiroga R. Perceptual and contextual awareness: methodological considerations in the search for the neural correlates of consciousness. Front Psychol 2014; 5:959. [PMID: 25221537 PMCID: PMC4148639 DOI: 10.3389/fpsyg.2014.00959] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 08/12/2014] [Indexed: 11/13/2022] Open
Abstract
In the last decades, the neural correlates of consciousness (NCCs) have been explored using both invasive and non-invasive recordings by comparing the brain activity elicited by seen versus unseen visual stimuli (i.e., the contrastive analysis). Here, we review a selection of these studies and discuss a set of considerations to improve the search for the NCCs using the contrastive analysis. In particular, we first argue in favor of implementing paradigms where different perceptual outputs are obtained using identical visual inputs. Second, we propose that the large disagreement in the field -in terms of the dissimilar neural patterns proposed as NCCs- is partially explained by the fact that different studies report the neural correlates of different conscious processes in the brain. More specifically, we distinguish between the perceptual awareness of a visual stimulus, associated to a boost in object-selective neural assemblies, and a more elaborate process (contextual awareness) that we argue is reflected in the firing of concept neurons in the medial temporal lobe, triggering a rich representation of the context, associations, and memories linked to the specific stimulus.
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Affiliation(s)
- Joaquin Navajas
- Centre for Systems Neuroscience, University of Leicester Leicester, UK
| | - Hernan G Rey
- Centre for Systems Neuroscience, University of Leicester Leicester, UK
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35
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Axelrod V, Rees G. Conscious awareness is required for holistic face processing. Conscious Cogn 2014; 27:233-45. [PMID: 24950500 PMCID: PMC4111907 DOI: 10.1016/j.concog.2014.05.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 04/22/2014] [Accepted: 05/07/2014] [Indexed: 11/24/2022]
Abstract
We explore unconscious holistic face processing using composite face stimulus. We test influence of the invisible faces on judgments of the visible eyes. We use three different sets of face stimuli and subliminal learning procedure. We show that invisible faces did not influence perception of visible eyes. Conscious awareness might be a prerequisite for holistic face processing.
Investigating the limits of unconscious processing is essential to understand the function of consciousness. Here, we explored whether holistic face processing, a mechanism believed to be important for face processing in general, can be accomplished unconsciously. Using a novel “eyes-face” stimulus we tested whether discrimination of pairs of eyes was influenced by the surrounding face context. While the eyes were fully visible, the faces that provided context could be rendered invisible through continuous flash suppression. Two experiments with three different sets of face stimuli and a subliminal learning procedure converged to show that invisible faces did not influence perception of visible eyes. In contrast, surrounding faces, when they were clearly visible, strongly influenced perception of the eyes. Thus, we conclude that conscious awareness might be a prerequisite for holistic face processing.
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Affiliation(s)
- Vadim Axelrod
- The Gonda Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan 52900, Israel; UCL Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK.
| | - Geraint Rees
- UCL Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK; Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3AR, UK
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