1
|
Meier ML, Vrana A, Schweinhardt P. Low Back Pain: The Potential Contribution of Supraspinal Motor Control and Proprioception. Neuroscientist 2019; 25:583-596. [PMID: 30387689 PMCID: PMC6900582 DOI: 10.1177/1073858418809074] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Motor control, which relies on constant communication between motor and sensory systems, is crucial for spine posture, stability and movement. Adaptions of motor control occur in low back pain (LBP) while different motor adaption strategies exist across individuals, probably to reduce LBP and risk of injury. However, in some individuals with LBP, adapted motor control strategies might have long-term consequences, such as increased spinal loading that has been linked with degeneration of intervertebral discs and other tissues, potentially maintaining recurrent or chronic LBP. Factors contributing to motor control adaptations in LBP have been extensively studied on the motor output side, but less attention has been paid to changes in sensory input, specifically proprioception. Furthermore, motor cortex reorganization has been linked with chronic and recurrent LBP, but underlying factors are poorly understood. Here, we review current research on behavioral and neural effects of motor control adaptions in LBP. We conclude that back pain-induced disrupted or reduced proprioceptive signaling likely plays a pivotal role in driving long-term changes in the top-down control of the motor system via motor and sensory cortical reorganization. In the outlook of this review, we explore whether motor control adaptations are also important for other (musculoskeletal) pain conditions.
Collapse
Affiliation(s)
- Michael Lukas Meier
- Integrative Spinal Research, Department of
Chiropractic Medicine, University Hospital Balgrist, Zurich, Switzerland
| | - Andrea Vrana
- Integrative Spinal Research, Department of
Chiropractic Medicine, University Hospital Balgrist, Zurich, Switzerland
| | - Petra Schweinhardt
- Integrative Spinal Research, Department of
Chiropractic Medicine, University Hospital Balgrist, Zurich, Switzerland
- Alan Edwards Center for Research on Pain,
McGill University, Montreal, Quebec, Canada
| |
Collapse
|
2
|
Peng Z, Braun DA. Entropic Movement Complexity Reflects Subjective Creativity Rankings of Visualized Hand Motion Trajectories. Front Psychol 2016; 6:1879. [PMID: 26733896 PMCID: PMC4681813 DOI: 10.3389/fpsyg.2015.01879] [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: 06/08/2015] [Accepted: 11/20/2015] [Indexed: 11/24/2022] Open
Abstract
In a previous study we have shown that human motion trajectories can be characterized by translating continuous trajectories into symbol sequences with well-defined complexity measures. Here we test the hypothesis that the motion complexity individuals generate in their movements might be correlated to the degree of creativity assigned by a human observer to the visualized motion trajectories. We asked participants to generate 55 novel hand movement patterns in virtual reality, where each pattern had to be repeated 10 times in a row to ensure reproducibility. This allowed us to estimate a probability distribution over trajectories for each pattern. We assessed motion complexity not only by the previously proposed complexity measures on symbolic sequences, but we also propose two novel complexity measures that can be directly applied to the distributions over trajectories based on the frameworks of Gaussian Processes and Probabilistic Movement Primitives. In contrast to previous studies, these new methods allow computing complexities of individual motion patterns from very few sample trajectories. We compared the different complexity measures to how a group of independent jurors rank ordered the recorded motion trajectories according to their personal creativity judgment. We found three entropic complexity measures that correlate significantly with human creativity judgment and discuss differences between the measures. We also test whether these complexity measures correlate with individual creativity in divergent thinking tasks, but do not find any consistent correlation. Our results suggest that entropic complexity measures of hand motion may reveal domain-specific individual differences in kinesthetic creativity.
Collapse
Affiliation(s)
- Zhen Peng
- Max Planck Institute for Biological CyberneticsTübingen, Germany; Max Planck Institute for Intelligent SystemsTübingen, Germany; International Max Planck Research School for Cognitive and Systems NeuroscienceTübingen, Germany
| | - Daniel A Braun
- Max Planck Institute for Biological CyberneticsTübingen, Germany; Max Planck Institute for Intelligent SystemsTübingen, Germany
| |
Collapse
|
3
|
Genewein T, Leibfried F, Grau-Moya J, Braun DA. Bounded Rationality, Abstraction, and Hierarchical Decision-Making: An Information-Theoretic Optimality Principle. Front Robot AI 2015. [DOI: 10.3389/frobt.2015.00027] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
|
4
|
Genewein T, Hez E, Razzaghpanah Z, Braun DA. Structure Learning in Bayesian Sensorimotor Integration. PLoS Comput Biol 2015; 11:e1004369. [PMID: 26305797 PMCID: PMC4549275 DOI: 10.1371/journal.pcbi.1004369] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 06/01/2015] [Indexed: 12/03/2022] Open
Abstract
Previous studies have shown that sensorimotor processing can often be described by Bayesian learning, in particular the integration of prior and feedback information depending on its degree of reliability. Here we test the hypothesis that the integration process itself can be tuned to the statistical structure of the environment. We exposed human participants to a reaching task in a three-dimensional virtual reality environment where we could displace the visual feedback of their hand position in a two dimensional plane. When introducing statistical structure between the two dimensions of the displacement, we found that over the course of several days participants adapted their feedback integration process in order to exploit this structure for performance improvement. In control experiments we found that this adaptation process critically depended on performance feedback and could not be induced by verbal instructions. Our results suggest that structural learning is an important meta-learning component of Bayesian sensorimotor integration. The human sensorimotor system has to process highly structured information that is affected by uncertainty and variability at all levels. Previously, it has been shown that sensorimotor processing is very efficient at extracting structure even in variable environments and it has also been shown how sensorimotor integration takes into account uncertainty when processing novel information. In particular, the latter integration process has been shown to be consistent with Bayesian theory. Here we show how the two processes of structure learning and sensorimotor integration work together in a single experiment. We find that when human participants learn a novel motor skill they not only successfully extract structural knowledge from variable data, but they also exploit this structural knowledge for near-optimal sensorimotor integration.
Collapse
Affiliation(s)
- Tim Genewein
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Max Planck Institute for Intelligent Systems, Tübingen, Germany
- Graduate Training Centre of Neuroscience, Tübingen, Germany
- * E-mail:
| | - Eduard Hez
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Max Planck Institute for Intelligent Systems, Tübingen, Germany
- University of Tübingen, Tübingen, Germany
| | - Zeynab Razzaghpanah
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Max Planck Institute for Intelligent Systems, Tübingen, Germany
- University of Tübingen, Tübingen, Germany
| | - Daniel A. Braun
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Max Planck Institute for Intelligent Systems, Tübingen, Germany
| |
Collapse
|
5
|
Understanding the role of the primary somatosensory cortex: Opportunities for rehabilitation. Neuropsychologia 2015; 79:246-55. [PMID: 26164474 DOI: 10.1016/j.neuropsychologia.2015.07.007] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 06/19/2015] [Accepted: 07/07/2015] [Indexed: 12/14/2022]
Abstract
Emerging evidence indicates impairments in somatosensory function may be a major contributor to motor dysfunction associated with neurologic injury or disorders. However, the neuroanatomical substrates underlying the connection between aberrant sensory input and ineffective motor output are still under investigation. The primary somatosensory cortex (S1) plays a critical role in processing afferent somatosensory input and contributes to the integration of sensory and motor signals necessary for skilled movement. Neuroimaging and neurostimulation approaches provide unique opportunities to non-invasively study S1 structure and function including connectivity with other cortical regions. These research techniques have begun to illuminate casual contributions of abnormal S1 activity and connectivity to motor dysfunction and poorer recovery of motor function in neurologic patient populations. This review synthesizes recent evidence illustrating the role of S1 in motor control, motor learning and functional recovery with an emphasis on how information from these investigations may be exploited to inform stroke rehabilitation to reduce motor dysfunction and improve therapeutic outcomes.
Collapse
|
6
|
Bauer R, Gharabaghi A. Reinforcement learning for adaptive threshold control of restorative brain-computer interfaces: a Bayesian simulation. Front Neurosci 2015; 9:36. [PMID: 25729347 PMCID: PMC4325901 DOI: 10.3389/fnins.2015.00036] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 01/24/2015] [Indexed: 02/04/2023] Open
Abstract
Restorative brain-computer interfaces (BCI) are increasingly used to provide feedback of neuronal states in a bid to normalize pathological brain activity and achieve behavioral gains. However, patients and healthy subjects alike often show a large variability, or even inability, of brain self-regulation for BCI control, known as BCI illiteracy. Although current co-adaptive algorithms are powerful for assistive BCIs, their inherent class switching clashes with the operant conditioning goal of restorative BCIs. Moreover, due to the treatment rationale, the classifier of restorative BCIs usually has a constrained feature space, thus limiting the possibility of classifier adaptation. In this context, we applied a Bayesian model of neurofeedback and reinforcement learning for different threshold selection strategies to study the impact of threshold adaptation of a linear classifier on optimizing restorative BCIs. For each feedback iteration, we first determined the thresholds that result in minimal action entropy and maximal instructional efficiency. We then used the resulting vector for the simulation of continuous threshold adaptation. We could thus show that threshold adaptation can improve reinforcement learning, particularly in cases of BCI illiteracy. Finally, on the basis of information-theory, we provided an explanation for the achieved benefits of adaptive threshold setting.
Collapse
Affiliation(s)
- Robert Bauer
- Division of Functional and Restorative Neurosurgery and Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University Tuebingen Tuebingen, Germany ; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery and Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University Tuebingen Tuebingen, Germany ; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
| |
Collapse
|
7
|
Peng Z, Genewein T, Braun DA. Assessing randomness and complexity in human motion trajectories through analysis of symbolic sequences. Front Hum Neurosci 2014; 8:168. [PMID: 24744716 PMCID: PMC3978291 DOI: 10.3389/fnhum.2014.00168] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 03/07/2014] [Indexed: 11/23/2022] Open
Abstract
Complexity is a hallmark of intelligent behavior consisting both of regular patterns and random variation. To quantitatively assess the complexity and randomness of human motion, we designed a motor task in which we translated subjects' motion trajectories into strings of symbol sequences. In the first part of the experiment participants were asked to perform self-paced movements to create repetitive patterns, copy pre-specified letter sequences, and generate random movements. To investigate whether the degree of randomness can be manipulated, in the second part of the experiment participants were asked to perform unpredictable movements in the context of a pursuit game, where they received feedback from an online Bayesian predictor guessing their next move. We analyzed symbol sequences representing subjects' motion trajectories with five common complexity measures: predictability, compressibility, approximate entropy, Lempel-Ziv complexity, as well as effective measure complexity. We found that subjects' self-created patterns were the most complex, followed by drawing movements of letters and self-paced random motion. We also found that participants could change the randomness of their behavior depending on context and feedback. Our results suggest that humans can adjust both complexity and regularity in different movement types and contexts and that this can be assessed with information-theoretic measures of the symbolic sequences generated from movement trajectories.
Collapse
Affiliation(s)
- Zhen Peng
- Max Planck Institute for Biological Cybernetics Tübingen, Germany ; Max Planck Institute for Intelligent Systems Tübingen, Germany ; Graduate Training Centre of Neuroscience Tübingen, Germany
| | - Tim Genewein
- Max Planck Institute for Biological Cybernetics Tübingen, Germany ; Max Planck Institute for Intelligent Systems Tübingen, Germany ; Graduate Training Centre of Neuroscience Tübingen, Germany
| | - Daniel A Braun
- Max Planck Institute for Biological Cybernetics Tübingen, Germany ; Max Planck Institute for Intelligent Systems Tübingen, Germany
| |
Collapse
|
8
|
Abstract
A large number of recent studies suggest that the sensorimotor system uses probabilistic models to predict its environment and makes inferences about unobserved variables in line with Bayesian statistics. One of the important features of Bayesian statistics is Occam's Razor--an inbuilt preference for simpler models when comparing competing models that explain some observed data equally well. Here, we test directly for Occam's Razor in sensorimotor control. We designed a sensorimotor task in which participants had to draw lines through clouds of noisy samples of an unobserved curve generated by one of two possible probabilistic models-a simple model with a large length scale, leading to smooth curves, and a complex model with a short length scale, leading to more wiggly curves. In training trials, participants were informed about the model that generated the stimulus so that they could learn the statistics of each model. In probe trials, participants were then exposed to ambiguous stimuli. In probe trials where the ambiguous stimulus could be fitted equally well by both models, we found that participants showed a clear preference for the simpler model. Moreover, we found that participants' choice behaviour was quantitatively consistent with Bayesian Occam's Razor. We also show that participants' drawn trajectories were similar to samples from the Bayesian predictive distribution over trajectories and significantly different from two non-probabilistic heuristics. In two control experiments, we show that the preference of the simpler model cannot be simply explained by a difference in physical effort or by a preference for curve smoothness. Our results suggest that Occam's Razor is a general behavioural principle already present during sensorimotor processing.
Collapse
Affiliation(s)
- Tim Genewein
- Max Planck Institute for Biological Cybernetics, , Tübingen, Germany, Max Planck Institute for Intelligent Systems, , Tübingen, Germany, Graduate Training Centre of Neuroscience, Tübingen, Germany
| | | |
Collapse
|
9
|
Gandolla M, Ferrante S, Molteni F, Guanziroli E, Frattini T, Martegani A, Ferrigno G, Friston K, Pedrocchi A, Ward NS. Re-thinking the role of motor cortex: context-sensitive motor outputs? Neuroimage 2014; 91:366-74. [PMID: 24440530 PMCID: PMC3988837 DOI: 10.1016/j.neuroimage.2014.01.011] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 12/05/2013] [Accepted: 01/05/2014] [Indexed: 12/05/2022] Open
Abstract
The standard account of motor control considers descending outputs from primary motor cortex (M1) as motor commands and efference copy. This account has been challenged recently by an alternative formulation in terms of active inference: M1 is considered as part of a sensorimotor hierarchy providing top–down proprioceptive predictions. The key difference between these accounts is that predictions are sensitive to the current proprioceptive context, whereas efference copy is not. Using functional electric stimulation to experimentally manipulate proprioception during voluntary movement in healthy human subjects, we assessed the evidence for context sensitive output from M1. Dynamic causal modeling of functional magnetic resonance imaging responses showed that FES altered proprioception increased the influence of M1 on primary somatosensory cortex (S1). These results disambiguate competing accounts of motor control, provide some insight into the synaptic mechanisms of sensory attenuation and may speak to potential mechanisms of action of FES in promoting motor learning in neurorehabilitation. Peripheral functional electrical stimulation provides altered proprioception. Altered proprioception and volitional movement interaction is shown in M1 and S1. M1–S1 connection is modulated by proprioception and therefore is context-sensitive. Context-sensitive M1–S1 pathway supports an active inference motor control account.
Collapse
Affiliation(s)
- Marta Gandolla
- Politecnico di Milano, NearLab, Department of Electronics, Information and Bioengineering, Via G. Colombo 40, 20133 Milano, Italy.
| | - Simona Ferrante
- Politecnico di Milano, NearLab, Department of Electronics, Information and Bioengineering, Via G. Colombo 40, 20133 Milano, Italy.
| | - Franco Molteni
- Valduce Hospital, Villa Beretta Rehabilitation Center, Via N. Sauro 17, 23845 Costamasnaga, LC, Italy.
| | - Eleonora Guanziroli
- Valduce Hospital, Villa Beretta Rehabilitation Center, Via N. Sauro 17, 23845 Costamasnaga, LC, Italy.
| | - Tiziano Frattini
- Valduce Hospital, Unità Operativa Complessa di Radiologia, via D. Alighieri 11, 22100 Como, Italy.
| | - Alberto Martegani
- Valduce Hospital, Unità Operativa Complessa di Radiologia, via D. Alighieri 11, 22100 Como, Italy.
| | - Giancarlo Ferrigno
- Politecnico di Milano, NearLab, Department of Electronics, Information and Bioengineering, Via G. Colombo 40, 20133 Milano, Italy.
| | - Karl Friston
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, 12 Queen Square, London WC1N 3BG, UK.
| | - Alessandra Pedrocchi
- Politecnico di Milano, NearLab, Department of Electronics, Information and Bioengineering, Via G. Colombo 40, 20133 Milano, Italy.
| | - Nick S Ward
- Sobell Department of Movement Neuroscience, UCL Institute of Neurology, 33 Queen Square, London WC1N 3BG, UK.
| |
Collapse
|
10
|
Narain D, Mamassian P, van Beers RJ, Smeets JBJ, Brenner E. How the statistics of sequential presentation influence the learning of structure. PLoS One 2013; 8:e62276. [PMID: 23638022 PMCID: PMC3634735 DOI: 10.1371/journal.pone.0062276] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 03/19/2013] [Indexed: 12/02/2022] Open
Abstract
Recent work has shown that humans can learn or detect complex dependencies among variables. Even learning a simple dependency involves the identification of an underlying model and the learning of its parameters. This process represents learning a structured problem. We are interested in an empirical assessment of some of the factors that enable humans to learn such a dependency over time. More specifically, we look at how the statistics of the presentation of samples from a given structure influence learning. Participants engage in an experimental task where they are required to predict the timing of a target. At the outset, they are oblivious to the existence of a relationship between the position of a stimulus and the required temporal response to intercept it. Different groups of participants are either presented with a Random Walk where consecutive stimuli were correlated or with stimuli that were uncorrelated over time. We find that the structural relationship implicit in the task is only learned in the conditions where the stimuli are independently drawn. This leads us to believe that humans require rich and independent sampling to learn hidden structures among variables.
Collapse
Affiliation(s)
- Devika Narain
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands.
| | | | | | | | | |
Collapse
|