1
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Dominik T, Mele A, Schurger A, Maoz U. Libet's legacy: A primer to the neuroscience of volition. Neurosci Biobehav Rev 2024; 157:105503. [PMID: 38072144 DOI: 10.1016/j.neubiorev.2023.105503] [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: 11/09/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023]
Abstract
The neuroscience of volition is an emerging subfield of the brain sciences, with hundreds of papers on the role of consciousness in action formation published each year. This makes the state-of-the-art in the discipline poorly accessible to newcomers and difficult to follow even for experts in the field. Here we provide a comprehensive summary of research in this field since its inception that will be useful to both groups. We also discuss important ideas that have received little coverage in the literature so far. We systematically reviewed a set of 2220 publications, with detailed consideration of almost 500 of the most relevant papers. We provide a thorough introduction to the seminal work of Benjamin Libet from the 1960s to 1980s. We also discuss common criticisms of Libet's method, including temporal introspection, the interpretation of the assumed physiological correlates of volition, and various conceptual issues. We conclude with recent advances and potential future directions in the field, highlighting modern methodological approaches to volition, as well as important recent findings.
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Affiliation(s)
| | - Alfred Mele
- Department of Philosophy, Florida State University, FL, USA
| | | | - Uri Maoz
- Brain Institute, Chapman University, CA, USA
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2
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Delnatte C, Roze E, Pouget P, Galléa C, Welniarz Q. Can neuroscience enlighten the philosophical debate about free will? Neuropsychologia 2023; 188:108632. [PMID: 37385373 DOI: 10.1016/j.neuropsychologia.2023.108632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/24/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Free will has been at the heart of philosophical and scientific discussions for many years. However, recent advances in neuroscience have been perceived as a threat to the commonsense notion of free will as they challenge two core requirements for actions to be free. The first is the notion of determinism and free will, i.e., decisions and actions must not be entirely determined by antecedent causes. The second is the notion of mental causation, i.e., our mental state must have causal effects in the physical world, in other words, actions are caused by conscious intention. We present the classical philosophical positions related to determinism and mental causation, and discuss how neuroscience could shed a new light on the philosophical debate based on recent experimental findings. Overall, we conclude that the current evidence is insufficient to undermine free will.
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Affiliation(s)
| | - Emmanuel Roze
- Sorbonne Université, Faculté de Médecine, INSERM U 1127, CNRS UMR 7225, Paris Brain Institute Institut du Cerveau, F-75013, Paris, France; Assistance Publique - Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Département de Neurologie, Paris, France
| | - Pierre Pouget
- Sorbonne Université, Faculté de Médecine, INSERM U 1127, CNRS UMR 7225, Paris Brain Institute Institut du Cerveau, F-75013, Paris, France
| | - Cécile Galléa
- Sorbonne Université, Faculté de Médecine, INSERM U 1127, CNRS UMR 7225, Paris Brain Institute Institut du Cerveau, F-75013, Paris, France
| | - Quentin Welniarz
- Sorbonne Université, Faculté de Médecine, INSERM U 1127, CNRS UMR 7225, Paris Brain Institute Institut du Cerveau, F-75013, Paris, France.
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3
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Triggiani AI, Kreiman G, Lewis C, Maoz U, Mele A, Mudrik L, Roskies AL, Schurger A, Hallett M. What is the intention to move and when does it occur? Neurosci Biobehav Rev 2023; 151:105199. [PMID: 37119992 PMCID: PMC10330627 DOI: 10.1016/j.neubiorev.2023.105199] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 04/04/2023] [Accepted: 04/24/2023] [Indexed: 05/01/2023]
Abstract
In 1983 Benjamin Libet and colleagues published a paper apparently challenging the view that the conscious intention to move precedes the brain's preparation for movement. The experiment initiated debates about the nature of intention, the neurophysiology of movement, and philosophical and legal understanding of free will and moral responsibility. Here we review the concept of "conscious intention" and attempts to measure its timing. Scalp electroencephalographic activity prior to movement, the Bereitschaftspotential, clearly begins prior to the reported onset of conscious intent. However, the interpretation of this finding remains controversial. Numerous studies show that the Libet method for determining intent, W time, is not accurate and may be misleading. We conclude that intention has many different aspects, and although we now understand much more about how the brain makes movements, identifying the time of conscious intention is still elusive.
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Affiliation(s)
- Antonio I Triggiani
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Gabriel Kreiman
- Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America, Center for Brains, Minds, and Machines, Cambridge, MA, USA
| | - Cara Lewis
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Uri Maoz
- Department of Psychology, Chapman University, Orange, CA 92866, USA; Institute for Interdisciplinary Brain and Behavioral Sciences, Chapman University, Irvine, CA 92618, USA; Anderson School of Management, University of California Los Angeles, Los Angeles, CA 90095, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Alfred Mele
- Department of Philosophy, Florida State University, Tallahassee, FL, USA
| | - Liad Mudrik
- School of Psychological Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Adina L Roskies
- Department of Philosophy, Dartmouth College, Hanover, NH 03755, USA
| | - Aaron Schurger
- Institute for Interdisciplinary Brain and Behavioral Sciences, Chapman University, Irvine, CA 92618, USA; INSERM U992, Cognitive Neuroimaging Unit, Neurospin Center, Gif-sur-Yvette 91191, France; Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, NeuroSpin Center, I2BM, Gif sur Yvette 91191, France
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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4
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Parés-Pujolràs E, Matić K, Haggard P. Feeling ready: neural bases of prospective motor readiness judgements. Neurosci Conscious 2023; 2023:niad003. [PMID: 36908683 PMCID: PMC9994593 DOI: 10.1093/nc/niad003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/12/2022] [Accepted: 02/02/2023] [Indexed: 03/14/2023] Open
Abstract
The idea that human agents voluntarily control their actions, including their spontaneous movements, strongly implies an anticipatory awareness of action. That is, agents should be aware they are about to act before actually executing a movement. Previous research has identified neural signals that could underpin prospective conscious access to motor preparation, including the readiness potential and the beta-band event-related desynchronization. In this study, we ran two experiments to test whether these two neural precursors of action also tracka subjective feeling of readiness. In Experiment 1, we combined a self-paced action task with an intention-probing design where participants gave binary responses to indicate whether they felt they had been about to move when a probe was presented. In Experiment 2, participants reported their feeling of readiness on a graded scale. We found that the feeling of readiness reliably correlates with the beta-band amplitude, but not with the readiness potential.
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Affiliation(s)
- Elisabeth Parés-Pujolràs
- Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AZ, UK.,School of Electrical and Electronic Engineering, University College Dublin, Dublin 4, Ireland.,Department of Biomedical Engineering, City College of the City University of New York, New York, NY 10031, USA
| | - Karla Matić
- Max Planck School of Cognition, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 304103, Germany.,Bernstein Center for Computational Neuroscience, Charité-Universitäts medizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin 10117, Germany.,Department of Psychology, Humboldt Universität zu Berlin, Berlin 12489, Germany
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AZ, UK.,Max Planck School of Cognition, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 304103, Germany
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5
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Lashgari E, Ott J, Connelly A, Baldi P, Maoz U. An end-to-end CNN with attentional mechanism applied to raw EEG in a BCI classification task. J Neural Eng 2021; 18. [PMID: 34352734 DOI: 10.1088/1741-2552/ac1ade] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/05/2021] [Indexed: 11/12/2022]
Abstract
Objective.Motor-imagery (MI) classification base on electroencephalography (EEG) has been long studied in neuroscience and more recently widely used in healthcare applications such as mobile assistive robots and neurorehabilitation. In particular, EEG-based MI classification methods that rely on convolutional neural networks (CNNs) have achieved relatively high classification accuracy. However, naively training CNNs to classify raw EEG data from all channels, especially for high-density EEG, is computationally demanding and requires huge training sets. It often also introduces many irrelevant input features, making it difficult for the CNN to extract the informative ones. This problem is compounded by a dearth of training data, which is particularly acute for MI tasks, because these are cognitively demanding and thus fatigue inducing.Approach.To address these issues, we proposed an end-to-end CNN-based neural network with attentional mechanism together with different data augmentation (DA) techniques. We tested it on two benchmark MI datasets, brain-computer interface (BCI) competition IV 2a and 2b. In addition, we collected a new dataset, recorded using high-density EEG, and containing both MI and motor execution (ME) tasks, which we share with the community.Main results.Our proposed neural-network architecture outperformed all state-of-the-art methods that we found in the literature, with and without DA, reaching an average classification accuracy of 93.6% and 87.83% on BCI 2a and 2b, respectively. We also directly compare decoding of MI and ME tasks. Focusing on MI classification, we find optimal channel configurations and the best DA techniques as well as investigate combining data across participants and the role of transfer learning.Significance.Our proposed approach improves the classification accuracy for MI in the benchmark datasets. In addition, collecting our own dataset enables us to compare MI and ME and investigate various aspects of EEG decoding critical for neuroscience and BCI.
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Affiliation(s)
- Elnaz Lashgari
- Schmid College of Science and Technology, Chapman University, Orange, CA, United States of America.,Institute for Interdisciplinary Brain and Behavioral Sciences, Chapman University, Orange, CA, United States of America
| | - Jordan Ott
- Department of Computer Science, University of California, Irvine, CA, United States of America
| | - Akima Connelly
- Schmid College of Science and Technology, Chapman University, Orange, CA, United States of America.,Institute for Interdisciplinary Brain and Behavioral Sciences, Chapman University, Orange, CA, United States of America
| | - Pierre Baldi
- Department of Computer Science, University of California, Irvine, CA, United States of America.,Center for Machine Learning and Intelligent Systems, University of California Irvine, Irvine, CA, United States of America.,Institute for Genomics and Bioinformatics, University of California Irvine, Irvine, CA, United States of America
| | - Uri Maoz
- Schmid College of Science and Technology, Chapman University, Orange, CA, United States of America.,Institute for Interdisciplinary Brain and Behavioral Sciences, Chapman University, Orange, CA, United States of America.,Computational Neuroscience and Psychology, Crean College of Health and Behavioral Sciences, Chapman University, Orange, CA, United States of America.,Fowler School of Engineering, Chapman University, Orange, CA, United States of America.,Anderson School of Management, University of California Los Angeles, Los Angeles, CA, United States of America.,Biology and Bioengineering, California Institute of Technology, Pasadena, CA, United States of America
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6
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Schultze-Kraft M, Parés-Pujolràs E, Matić K, Haggard P, Haynes JD. Preparation and execution of voluntary action both contribute to awareness of intention. Proc Biol Sci 2020; 287:20192928. [PMID: 32208835 DOI: 10.1098/rspb.2019.2928] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
How and when motor intentions form has long been controversial. In particular, the extent to which motor preparation and action-related processes produce a conscious experience of intention remains unknown. Here, we used a brain-computer interface (BCI) while participants performed a self-paced movement task to trigger cues upon the detection of a readiness potential (a well-characterized brain signal that precedes movement) or in its absence. The BCI-triggered cues instructed participants either to move or not to move. Following this instruction, participants reported whether they felt they were about to move at the time the cue was presented. Participants were more likely to report an intention (i) when the cue was triggered by the presence of a readiness potential than when the same cue was triggered by its absence, and (ii) when they had just made an action than when they had not. We further describe a time-dependent integration of these two factors: the probability of reporting an intention was maximal when cues were triggered in the presence of a readiness potential, and when participants also executed an action shortly afterwards. Our results provide a first systematic investigation of how prospective and retrospective components are integrated in forming a conscious intention to move.
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Affiliation(s)
- Matthias Schultze-Kraft
- Bernstein Center for Computational Neuroscience, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Center for Advanced Neuroimaging, Charité-Universitätsmedizin Berlin, Berlin, Germany.,SFB 940 Volition and Cognitive Control, Technische Universität Dresden, Dresden, Germany
| | | | - Karla Matić
- Bernstein Center for Computational Neuroscience, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Laboratory of Experimental Psychology, KU Leuven, Louvain, Belgium
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London, London, UK.,Laboratoire des Neuroscience Cognitives, Département d'Études Cognitives, École Normale Supérieure, PSL University, Paris, France
| | - John-Dylan Haynes
- Bernstein Center for Computational Neuroscience, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Center for Advanced Neuroimaging, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Clinic of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,SFB 940 Volition and Cognitive Control, Technische Universität Dresden, Dresden, Germany.,Department of Psychology, Humboldt Universität zu Berlin, Berlin, Germany.,Excellence Cluster Science of Intelligence, Technische Universität Berlin and Humbold Universität zu Berlin, Berlin, Germany
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7
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Brass M, Furstenberg A, Mele AR. Why neuroscience does not disprove free will. Neurosci Biobehav Rev 2019; 102:251-263. [PMID: 31059730 DOI: 10.1016/j.neubiorev.2019.04.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 10/26/2022]
Abstract
While the question whether free will exists or not has concerned philosophers for centuries, empirical research on this question is relatively young. About 35 years ago Benjamin Libet designed an experiment that challenged the common intuition of free will, namely that conscious intentions are causally efficacious. Libet demonstrated that conscious intentions are preceded by a specific pattern of brain activation, suggesting that unconscious processes determine our decisions and we are only retrospectively informed about these decisions. Libet-style experiments have ever since dominated the discourse about the existence of free will and have found their way into the public media. Here we review the most important challenges to the common interpretation of Libet-style tasks and argue that the common interpretation is questionable. Brain activity preceding conscious decisions reflects the decision process rather than its outcome. Furthermore, the decision process is configured by conditional intentions that participants form at the beginning of the experiment. We conclude that Libet-style tasks do not provide a serious challenge to our intuition of free will.
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Affiliation(s)
- Marcel Brass
- Department of Experimental Psychology, Ghent University, Henri Dunantlaan 2, Ghent, 9000, Belgium.
| | - Ariel Furstenberg
- Racah Institute of Physics, Edmond and Lily Safra Center for Brain Sciences, The Hebrew University Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel.
| | - Alfred R Mele
- Department of Philosophy, Florida State University, 151 Dodd Hall, Tallahassee, 32306-1500, USA.
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8
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Verbaarschot C, Haselager P, Farquhar J. Probing for Intentions: Why Clocks Do Not Provide the Only Measurement of Time. Front Hum Neurosci 2019; 13:68. [PMID: 30914934 PMCID: PMC6423073 DOI: 10.3389/fnhum.2019.00068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 02/11/2019] [Indexed: 11/22/2022] Open
Abstract
Having an intention to act is commonly operationalized as the moment at which awareness of an urge or decision to act arises. Measuring this moment has been challenging due to the dependence on first-person reports of subjective experience rather than objective behavioral or neural measurements. Commonly, this challenge is met using (variants of) Libet's clock method. In 2008, Matsuhashi and Hallett published a novel probing strategy as an alternative to the clock method. We believe their probe method could provide a valuable addition to the clock method because: it measures the timing of an intention in real-time, it can be combined with additional (tactile, visual or auditory) stimuli to create a more ecologically valid experimental context, and it allows the measurement of the point of no return. Yet to this date, the probe method has not been applied widely - possibly due to concerns about the effects that the probes might have on the intention and/or action preparation processes. To address these concerns, a 2 × 2 within-subject design is tested. In this design, two variables are manipulated: (1) the requirement of an introspection report and (2) the presence of an auditory probe. Three observables are measured that provide information about the timing of an intention to act: (1) awareness reports of the subjective experience of having an intention, (2) neural preparatory activity for action, and (3) behavioral data of the performed actions. The presence of probes was found to speed up mean action times by roughly 300 ms, but did not alter the neural preparation for action. The requirement of an introspection report did influence brain signals: reducing the amplitude of the readiness potential and increasing the desynchronization in the alpha and beta bands over the motor cortex prior to action onset. By discussing the strengths and weaknesses of the probe method compared to the clock method, we hope to demonstrate its added value and promote its use in future research.
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Affiliation(s)
- Ceci Verbaarschot
- Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Pim Haselager
- Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Jason Farquhar
- Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
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9
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Hallett M. Physiology of free will. Ann Neurol 2016; 80:5-12. [PMID: 27042814 DOI: 10.1002/ana.24657] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 03/20/2016] [Accepted: 03/27/2015] [Indexed: 01/07/2023]
Abstract
Free will is a perception that people have that they choose to make their movements. This perception includes a sense of willing the movement and self-agency that they are responsible for the movement. If there is a "free will force" that plays a role in movement selection, it should precede movement. There is no evidence for a driving force, and the perception of willing is not fully processed until after the movement. The perceptions of free will likely arise from an interaction between frontal and parietal areas. Free will might be considered to exist if a person's brain is functioning normally without coercion. Ann Neurol 2016;80:5-12.
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Affiliation(s)
- Mark Hallett
- Human Motor Control Section, NINDS, Bethesda, MD
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10
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Verbaarschot C, Haselager P, Farquhar J. Detecting traces of consciousness in the process of intending to act. Exp Brain Res 2016; 234:1945-1956. [PMID: 26920393 PMCID: PMC4893062 DOI: 10.1007/s00221-016-4600-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/14/2016] [Indexed: 11/26/2022]
Abstract
An intention to act has different onsets when it is measured in different ways. When participants provide a self-initiated report on the onset of their awareness of intending to act, the report occurs around 150 ms prior to action. However, when the same participants are repeatedly asked about their awareness of intending at different points in time, the onset of intending is found up to 2 s prior to action. This ‘probed’ awareness has its onset around the same time as the brain starts preparing the act, as measured using EEG. First of all, this undermines straightforward interpretations about the temporal relation between unconscious brain states and conscious intentions and actions. Secondly, we suggest that these results present a problem for the view that intentions are mental states occurring at a single point in time. Instead, we suggest the results to support the interpretation of an intention to act as a multistage process developing over time. This process of intending seems to develop during the process of acting, leaving reportable traces in consciousness at certain points along the road.
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Affiliation(s)
- Ceci Verbaarschot
- Center for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, PO Box 9104, 6500 HE, Nijmegen, The Netherlands.
| | - Pim Haselager
- Center for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, PO Box 9104, 6500 HE, Nijmegen, The Netherlands
| | - Jason Farquhar
- Center for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, PO Box 9104, 6500 HE, Nijmegen, The Netherlands
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11
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Ludwig VU, Seitz J, Schönfeldt-Lecuona C, Höse A, Abler B, Hole G, Goebel R, Walter H. The neural correlates of movement intentions: A pilot study comparing hypnotic and simulated paralysis. Conscious Cogn 2015; 35:158-70. [PMID: 26036837 DOI: 10.1016/j.concog.2015.05.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 04/27/2015] [Accepted: 05/14/2015] [Indexed: 11/29/2022]
Abstract
The distinct feeling of wanting to act and thereby causing our own actions is crucial to our self-perception as free human agents. Disturbances of the link between intention and action occur in several disorders. Little is known, however, about the neural correlates of wanting or intending to act. To investigate these for simple voluntary movements, we used a paradigm involving hypnotic paralysis and functional magnetic resonance imaging. Eight healthy women were instructed to sequentially perform left and right hand movements during a normal condition, as well as during simulated weakness, simulated paralysis and hypnotic paralysis of the right hand. Right frontopolar cortex was selectively hypoactivated for attempted right hand movement during simulated paralysis while it was active in all other conditions. Since simulated paralysis was the only condition lacking an intention to move, the activation in frontopolar cortex might be related to the intention or volition to move.
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Affiliation(s)
- Vera U Ludwig
- Division of Mind and Brain Research, Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany.
| | - Jochen Seitz
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, University Hospital, RWTH University Aachen, Neuenhofer Weg 21, 52074 Aachen, Germany; Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
| | - Carlos Schönfeldt-Lecuona
- Department of Psychiatry and Psychotherapy III, University Hospital Ulm, Leimgrubenweg 12-14, 89075 Ulm, Germany.
| | - Annett Höse
- Department of Psychiatry and Psychotherapy III, University Hospital Ulm, Leimgrubenweg 12-14, 89075 Ulm, Germany.
| | - Birgit Abler
- Department of Psychiatry and Psychotherapy III, University Hospital Ulm, Leimgrubenweg 12-14, 89075 Ulm, Germany.
| | - Günter Hole
- Aus- und Weiterbildungsinstitut für Hypnosetherapie, Kantstr. 5/3, D-88213 Ravensburg, Germany
| | - Rainer Goebel
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands; Maastricht Brain Imaging Centre, Faculty of Psychology and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
| | - Henrik Walter
- Division of Mind and Brain Research, Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany.
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12
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Do meditators have higher awareness of their intentions to act? Cortex 2015; 65:149-58. [DOI: 10.1016/j.cortex.2014.12.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 10/16/2014] [Accepted: 12/16/2014] [Indexed: 11/22/2022]
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13
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Bode S, Murawski C, Soon CS, Bode P, Stahl J, Smith PL. Demystifying “free will”: The role of contextual information and evidence accumulation for predictive brain activity. Neurosci Biobehav Rev 2014; 47:636-45. [DOI: 10.1016/j.neubiorev.2014.10.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 08/19/2014] [Accepted: 10/20/2014] [Indexed: 10/24/2022]
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14
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Abstract
The ability to decode an individual's intentions in real time has long been a ‘holy grail’ of research on human volition. For example, a reliable method could be used to improve scientific study of voluntary action by allowing external probe stimuli to be delivered at different moments during development of intention and action. Several Brain Computer Interface applications have used motor imagery of repetitive actions to achieve this goal. These systems are relatively successful, but only if the intention is sustained over a period of several seconds; much longer than the timescales identified in psychophysiological studies for normal preparation for voluntary action. We have used a combination of sensorimotor rhythms and motor imagery training to decode intentions in a single-trial cued-response paradigm similar to those used in human and non-human primate motor control research. Decoding accuracy of over 0.83 was achieved with twelve participants. With this approach, we could decode intentions to move the left or right hand at sub-second timescales, both for instructed choices instructed by an external stimulus and for free choices generated intentionally by the participant. The implications for volition are considered.
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Affiliation(s)
- Mathew Salvaris
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom
- * E-mail:
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom
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15
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Zschorlich VR, Köhling R. How thoughts give rise to action - conscious motor intention increases the excitability of target-specific motor circuits. PLoS One 2013; 8:e83845. [PMID: 24386291 PMCID: PMC3873337 DOI: 10.1371/journal.pone.0083845] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 11/18/2013] [Indexed: 11/18/2022] Open
Abstract
The present study shows evidence for conscious motor intention in motor preparation prior to movement execution. We demonstrate that conscious motor intention of directed movement, combined with minimally supra-threshold transcranial magnetic stimulation (TMS) of the motor cortex, determines the direction and the force of resulting movements, whilst a lack of intention results in weak and omni-directed muscle activation. We investigated changes of consciously intended goal directed movements by analyzing amplitudes of motor-evoked potentials of the forearm muscle, flexor carpi radialis (FCR), and extensor carpi radialis (ECR), induced by transcranial magnetic stimulation over the right motor cortex and their motor outcome. Right-handed subjects were asked to develop a strong intention to move their left wrist (flexion or extension), without any overt motor output at the wrist, prior to brain stimulation. Our analyses of hand acceleration and electromyography showed that during the strong motor intention of wrist flexion movement, it evoked motor potential responses that were significantly larger in the FCR muscle than in the ECR, whilst the opposite was true for an extension movement. The acceleration data on flexion/extension corresponded to this finding. Under no-intention conditions again, which served as a reference for motor evoked potentials, brain stimulation resulted in undirected and minimally simultaneous extension/flexion innervation and virtually no movement. These results indicate that conscious intentions govern motor function, which in turn shows that a neuronal activation representing an “intention network” in the human brain pre-exists, and that it functionally represents target specific motor circuits. Until today, it was unclear whether conscious motor intention exists prior to movement, or whether the brain constructs such an intention after movement initiation. Our study gives evidence that motor intentions become aware before any motor execution.
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Affiliation(s)
- Volker R. Zschorlich
- Department of Movement Science, University of Rostock, Rostock, Germany
- Interdisciplinary Faculty - Department of Aging Science, University of Rostock, Rostock, Germany
- Faculty of Medicine, University of Rostock, Rostock, Germany
- Faculty of Philosophy, University of Rostock, Rostock, Germany
- * E-mail: (VRZ); (RK)
| | - Rüdiger Köhling
- Interdisciplinary Faculty - Department of Aging Science, University of Rostock, Rostock, Germany
- Faculty of Medicine, University of Rostock, Rostock, Germany
- Oscar-Langendorff-Institute of Physiology, University of Rostock, Rostock, Germany
- * E-mail: (VRZ); (RK)
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Abstract
Abstract
It is typically assumed that the conscious experience of wanting to move is not the driving force for motor planning, but the secondary consequence of the unconscious neural processes preparing the movement. A recent study by Schneider et al. [Schneider, L., Houdayer, E., Bai, O., & Hallett, M. What we think before a voluntary movement. Journal of Cognitive Neuroscience, 25, 822–829, 2013] seems consistent with this dominant view by showing that the brain can be preparing to make voluntary movements not only “prior to the conscious appreciation that this is happening” but also “while subjects are thinking about something else.” However, an alternative hypothesis exists. It is supported by several lines of evidence and suggests that the early neural signals recorded by Schneider et al. (and others) do not reflect movement preparation per se, but rather a buildup in neural activity that ultimately leads to the emergence of a conscious intention to move. According to this view, the conscious experience of wanting to move is not the consequence but the cause of movement initiation.
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Affiliation(s)
- Michel Desmurget
- 1Centre de Neuroscience Cognitive, CNRS, UMR 5229, Bron, France
- 2Université Claude Bernard, Lyon
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