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Ko DK, Lee H, Lee H, Kang N. Bilateral ankle dorsiflexion force control impairments in older adults. PLoS One 2025; 20:e0319578. [PMID: 40112015 PMCID: PMC11925285 DOI: 10.1371/journal.pone.0319578] [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: 12/02/2024] [Accepted: 02/04/2025] [Indexed: 03/22/2025] Open
Abstract
Age-related impairments in ankle dorsiflexion force modulation are associated with gait and balance control deficits and greater fall risk in older adults. This study aimed to investigate age-related changes in bilateral ankle dorsiflexion force control capabilities compared with those for younger adults. The study enrolled 25 older and 25 younger adults. They performed bilateral ankle dorsiflexion force control at 10% and 40% of maximum voluntary contraction (MVC), for vision and no-vision conditions, respectively. Bilateral force control performances were evaluated by calculating force accuracy, variability, and complexity. To estimate bilateral force coordination between feet, vector coding and uncontrolled manifold variables were quantified. Additional correlation analyses were performed to determine potential relationships between age and force control variables in older adults. Older adults demonstrated significantly lower force accuracy with greater overshooting at 10% of MVC than those for younger adults. At 10% and 40% of MVC, older adults significantly showed more variable and less complex force outputs, and these patterns appeared in both vision and no-vision conditions. Moreover, older adults revealed significantly less anti-phase force coordination patterns and lower bilateral motor synergies with increased bad variability than younger adults. The correlation analyses found that lower complexity of bilateral forces was significantly related to increased age. These findings suggest that aging may impair sensorimotor control capabilities in the lower extremities. Considering the importance of ankle dorsiflexion for executing many activities of daily living, future studies may focus on developing training programs for advancing bilateral ankle dorsiflexion force control capabilities.
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Affiliation(s)
- Do-Kyung Ko
- Department of Human Movement Science, Incheon National University, Incheon, South Korea
- Neuromechanical Rehabilitation Research Laboratory, Incheon National University, Incheon, South Korea
| | - Hanall Lee
- Department of Human Movement Science, Incheon National University, Incheon, South Korea
- Neuromechanical Rehabilitation Research Laboratory, Incheon National University, Incheon, South Korea
| | - Hajun Lee
- Department of Human Movement Science, Incheon National University, Incheon, South Korea
- Neuromechanical Rehabilitation Research Laboratory, Incheon National University, Incheon, South Korea
| | - Nyeonju Kang
- Department of Human Movement Science, Incheon National University, Incheon, South Korea
- Neuromechanical Rehabilitation Research Laboratory, Incheon National University, Incheon, South Korea
- Division of Sport Science, Sport Science Institute and Health Promotion Center, Incheon National University, Incheon, South Korea
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Wulff-Abramsson A, Zvornik A, Andersen KA, Yang Y, Novén M, Lundbye-Jensen J, Tomasevic L, Karabanov AN. Event-related theta synchronization over sensorimotor areas differs between younger and older adults and is related to bimanual motor control. Neuroimage 2025; 308:121032. [PMID: 39863003 DOI: 10.1016/j.neuroimage.2025.121032] [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: 10/16/2024] [Revised: 01/14/2025] [Accepted: 01/16/2025] [Indexed: 01/27/2025] Open
Abstract
When engaged in dynamic or continuous movements, action initiation involves modifying an ongoing motor program rather than initiating it from rest. Event-related theta synchronization over sensorimotor areas is a neurophysiological marker for modifying motor programs. We used electroencephalography (EEG) to examine how task complexity and age affect event-related synchronization (ERS) in the theta band during a dynamic bimanual, visuomotor pinch force task. Older (mean age = 68) and younger (mean age = 26) participants performed symmetric (SYM) and asymmetric (ASYM) bimanual pinch force adjustments. Trials began with a visually cued contraction from a baseline force to a novel target force (P1). Force had to be maintained at the target until a visually cued return to the familiar baseline (P2). Older adults reacted slower across task conditions, and their accuracy decreased more when shifting from the SYM to the ASYM condition. Older adults also displayed lower theta ERS across conditions. Additionally, older adults were not able to modulate theta expression based on whether a force change was initiated to a novel target or back to baseline. Younger adults showed significantly stronger theta ERS after P1-cues compared to P2-cues, while the theta response to P1 and P2 cues was not different in older adults. Older adults also showed stronger lateralization, displaying higher theta ERS over the dominant motor cortex. Finally, event-related theta synchronization appeared to be behaviorally relevant across groups and correlated with task performance. Together, the results show that theta ERS over sensorimotor areas is a strong, age-sensitive marker of dynamic pinch force adjustments showing an age-related reduction in specificity with reduced context-dependent modulations and more imbalanced bimanual activation.
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Affiliation(s)
- Andreas Wulff-Abramsson
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Ana Zvornik
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Keenie Ayla Andersen
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Yan Yang
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences
| | - Mikael Novén
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Jesper Lundbye-Jensen
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Leo Tomasevic
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark; Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany; Department of Human Sciences, Institute of Psychology, University of the Bundeswehr Munich, Neubiberg, Germany
| | - Anke Ninija Karabanov
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.
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Nielsen AL, Norup M, Bjørndal JR, Wiegel P, Spedden ME, Lundbye-Jensen J. Increased functional and directed corticomuscular connectivity after dynamic motor practice but not isometric motor practice. J Neurophysiol 2025; 133:930-943. [PMID: 39951554 DOI: 10.1152/jn.00061.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 06/30/2024] [Accepted: 02/12/2025] [Indexed: 02/16/2025] Open
Abstract
How do differences in the constraints of a practiced motor task affect oscillatory functional connectivity between the motor cortex and muscle? Here, we investigate corticomuscular (CM) and intermuscular (IM) coherence during the hold-phase of a dynamic position control (PC) and isometric force control (FC) task. We also investigate the effects of PC motor practice requiring precise wrist flexions to designated target positions, and effects of FC motor practice involving isometric wrist flexions to designated target force levels or rest in a control group. In 46 young healthy adults (aged 20-30 yr), full-cap electroencephalography (EEG) and electromyography (EMG) were recorded from the flexor and extensor carpi radialis muscles during the tasks. Beta-band (15-35 Hz) CM and IM coherence were investigated as a task-related marker of oscillatory activity in the corticospinal system. At baseline, higher CM coupling was demonstrated during position control compared with force control. Following PC motor practice, CM β-band coherence increased (P = 0.038), whereas it remained unchanged for participants who practiced FC or rested. This pattern was also found for IM coherence. The increased oscillatory synchronization following PC practice was driven by greater descending signaling (P = 0.025). We speculate that the observed differences between position and force control relate to task differences in corticomuscular control-strategy and the influence of different sensory modalities during motor practice. We interpret the results as indicating increased coupling between the motor cortex and the motoneuron pool of the contracting muscle following dynamic motor practice emphasizing requirements for position control in motor learning.NEW & NOTEWORTHY We present the effects of different types of motor practice on functional connectivity in the corticomuscular system. We present differences in corticomuscular connectivity between tasks with position versus force control emphasis and evidence for increased functional and directed connectivity within the network specifically following position-control motor practice. These findings support using different control strategies based on task constraints and emphasize the importance of dynamic motor practice focused on position control for increasing coherence.
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Affiliation(s)
- August Lomholt Nielsen
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Malene Norup
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
- Department of Midwifery, Physiotherapy, Occupational Therapy and Psychomotor Therapy, Faculty of Health, University College Copenhagen, Copenhagen, Denmark
| | - Jonas Rud Bjørndal
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Patrick Wiegel
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
- Agaplesion Bethesda Clinic Ulm, Ulm, Germany
- Institute for Geriatric Research, Ulm University, Ulm, Germany
| | - Meaghan Elizabeth Spedden
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
- Wellcome Centre for Human Neuroimaging, Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Jesper Lundbye-Jensen
- Movement & Neuroscience, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Shen B, Xiao S, Yu C, Zhang C, Zhan J, Liu Y, Fu W. Cerebral hemodynamics underlying ankle force sense modulated by high-definition transcranial direct current stimulation. Cereb Cortex 2024; 34:bhae226. [PMID: 38850217 DOI: 10.1093/cercor/bhae226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/07/2024] [Accepted: 05/14/2024] [Indexed: 06/10/2024] Open
Abstract
This study aimed to investigate the effects of high-definition transcranial direct current stimulation on ankle force sense and underlying cerebral hemodynamics. Sixteen healthy adults (8 males and 8 females) were recruited in the study. Each participant received either real or sham high-definition transcranial direct current stimulation interventions in a randomly assigned order on 2 visits. An isokinetic dynamometer was used to assess the force sense of the dominant ankle; while the functional near-infrared spectroscopy was employed to monitor the hemodynamics of the sensorimotor cortex. Two-way analyses of variance with repeated measures and Pearson correlation analyses were performed. The results showed that the absolute error and root mean square error of ankle force sense dropped more after real stimulation than after sham stimulation (dropped by 23.4% vs. 14.9% for absolute error, and 20.0% vs. 10.2% for root mean square error). The supplementary motor area activation significantly increased after real high-definition transcranial direct current stimulation. The decrease in interhemispheric functional connectivity within the Brodmann's areas 6 was significantly correlated with ankle force sense improvement after real high-definition transcranial direct current stimulation. In conclusion, high-definition transcranial direct current stimulation can be used as a potential intervention for improving ankle force sense. Changes in cerebral hemodynamics could be one of the explanations for the energetic effect of high-definition transcranial direct current stimulation.
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Affiliation(s)
- Bin Shen
- School of Exercise and Health, Shanghai University of Sport, 200 Hengren Road, Yangpu District, Shanghai 200438, China
| | - Songlin Xiao
- School of Exercise and Health, Shanghai University of Sport, 200 Hengren Road, Yangpu District, Shanghai 200438, China
| | - Changxiao Yu
- School of Exercise and Health, Shanghai University of Sport, 200 Hengren Road, Yangpu District, Shanghai 200438, China
| | - Chuyi Zhang
- School of Exercise and Health, Shanghai University of Sport, 200 Hengren Road, Yangpu District, Shanghai 200438, China
| | - Jianglong Zhan
- School of Exercise and Health, Shanghai University of Sport, 200 Hengren Road, Yangpu District, Shanghai 200438, China
| | - Ying Liu
- School of Psychology, Shanghai University of Sport, 399 Changhai Road, Yangpu District, Shanghai 200438, China
| | - Weijie Fu
- School of Exercise and Health, Shanghai University of Sport, 200 Hengren Road, Yangpu District, Shanghai 200438, China
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, 200 Hengren Road, Yangpu District, Shanghai 200438, China
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Almohammadi A, Wang YK. Revealing brain connectivity: graph embeddings for EEG representation learning and comparative analysis of structural and functional connectivity. Front Neurosci 2024; 17:1288433. [PMID: 38264495 PMCID: PMC10804888 DOI: 10.3389/fnins.2023.1288433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 12/04/2023] [Indexed: 01/25/2024] Open
Abstract
This study employs deep learning techniques to present a compelling approach for modeling brain connectivity in EEG motor imagery classification through graph embedding. The compelling aspect of this study lies in its combination of graph embedding, deep learning, and different brain connectivity types, which not only enhances classification accuracy but also enriches the understanding of brain function. The approach yields high accuracy, providing valuable insights into brain connections and has potential applications in understanding neurological conditions. The proposed models consist of two distinct graph-based convolutional neural networks, each leveraging different types of brain connectivities to enhance classification performance and gain a deeper understanding of brain connections. The first model, Adjacency-based Convolutional Neural Network Model (Adj-CNNM), utilizes a graph representation based on structural brain connectivity to embed spatial information, distinguishing it from prior spatial filtering approaches dependent on subjects and tasks. Extensive tests on a benchmark dataset-IV-2a demonstrate that an accuracy of 72.77% is achieved by the Adj-CNNM, surpassing baseline and state-of-the-art methods. The second model, Phase Locking Value Convolutional Neural Network Model (PLV-CNNM), incorporates functional connectivity to overcome structural connectivity limitations and identifies connections between distinct brain regions. The PLV-CNNM achieves an overall accuracy of 75.10% across the 1-51 Hz frequency range. In the preferred 8-30 Hz frequency band, known for motor imagery data classification (including α, μ, and β waves), individual accuracies of 91.9%, 90.2%, and 85.8% are attained for α, μ, and β, respectively. Moreover, the model performs admirably with 84.3% accuracy when considering the entire 8-30 Hz band. Notably, the PLV-CNNM reveals robust connections between different brain regions during motor imagery tasks, including the frontal and central cortex and the central and parietal cortex. These findings provide valuable insights into brain connectivity patterns, enriching the comprehension of brain function. Additionally, the study offers a comprehensive comparative analysis of diverse brain connectivity modeling methods.
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Affiliation(s)
- Abdullah Almohammadi
- School of Computer Science, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, Australia
- College of Computer Science and Engineering, Taibah University, Madinah, Saudia Arabia
| | - Yu-Kai Wang
- School of Computer Science, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, Australia
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Artoni F, Cometa A, Dalise S, Azzollini V, Micera S, Chisari C. Cortico-muscular connectivity is modulated by passive and active Lokomat-assisted Gait. Sci Rep 2023; 13:21618. [PMID: 38062035 PMCID: PMC10703891 DOI: 10.1038/s41598-023-48072-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
The effects of robotic-assisted gait (RAG) training, besides conventional therapy, on neuroplasticity mechanisms and cortical integration in locomotion are still uncertain. To advance our knowledge on the matter, we determined the involvement of motor cortical areas in the control of muscle activity in healthy subjects, during RAG with Lokomat, both with maximal guidance force (100 GF-passive RAG) and without guidance force (0 GF-active RAG) as customary in rehabilitation treatments. We applied a novel cortico-muscular connectivity estimation procedure, based on Partial Directed Coherence, to jointly study source localized EEG and EMG activity during rest (standing) and active/passive RAG. We found greater cortico-cortical connectivity, with higher path length and tendency toward segregation during rest than in both RAG conditions, for all frequency bands except for delta. We also found higher cortico-muscular connectivity in distal muscles during swing (0 GF), and stance (100 GF), highlighting the importance of direct supraspinal control to maintain balance, even when gait is supported by a robotic exoskeleton. Source-localized connectivity shows that this control is driven mainly by the parietal and frontal lobes. The involvement of many cortical areas also in passive RAG (100 GF) justifies the use of the 100 GF RAG training for neurorehabilitation, with the aim of enhancing cortical-muscle connections and driving neural plasticity in neurological patients.
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Affiliation(s)
- Fiorenzo Artoni
- Department of Clinical Neurosciences, University of Genève, Faculty of Medicine, 1211, Geneva, Switzerland.
- Ago Neurotechnologies Sàrl, 1201, Geneva, Switzerland.
| | - Andrea Cometa
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025, Pontedera, Italy
- University School for Advanced Studies IUSS Pavia, 27100, Pavia, Italy
| | - Stefania Dalise
- Unit of Neurorehabilitation, Pisa University Hospital, Pisa, Italy
| | - Valentina Azzollini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Silvestro Micera
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025, Pontedera, Italy
- Translational Neural Engineering Laboratory (TNE), École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
| | - Carmelo Chisari
- Unit of Neurorehabilitation, Pisa University Hospital, Pisa, Italy
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
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Xiao S, Shen B, Zhang C, Xu Z, Li J, Fu W, Jin J. Effects of tDCS on Foot Biomechanics: A Narrative Review and Clinical Applications. Bioengineering (Basel) 2023; 10:1029. [PMID: 37760131 PMCID: PMC10525503 DOI: 10.3390/bioengineering10091029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/13/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
In recent years, neuro-biomechanical enhancement techniques, such as transcranial direct current stimulation (tDCS), have been widely used to improve human physical performance, including foot biomechanical characteristics. This review aims to summarize research on the effects of tDCS on foot biomechanics and its clinical applications, and further analyze the underlying ergogenic mechanisms of tDCS. This review was performed for relevant papers until July 2023 in the following databases: Web of Science, PubMed, and EBSCO. The findings demonstrated that tDCS can improve foot biomechanical characteristics in healthy adults, including proprioception, muscle strength, reaction time, and joint range of motion. Additionally, tDCS can be effectively applied in the field of foot sports medicine; in particular, it can be combined with functional training to effectively improve foot biomechanical performance in individuals with chronic ankle instability (CAI). The possible mechanism is that tDCS may excite specific task-related neurons and regulate multiple neurons within the system, ultimately affecting foot biomechanical characteristics. However, the efficacy of tDCS applied to rehabilitate common musculoskeletal injuries (e.g., CAI and plantar fasciitis) still needs to be confirmed using a larger sample size. Future research should use multimodal neuroimaging technology to explore the intrinsic ergogenic mechanism of tDCS.
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Affiliation(s)
- Songlin Xiao
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China; (S.X.)
| | - Bin Shen
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China; (S.X.)
| | - Chuyi Zhang
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China; (S.X.)
| | - Zhen Xu
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China; (S.X.)
| | - Jingjing Li
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China; (S.X.)
| | - Weijie Fu
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China; (S.X.)
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai 200438, China
| | - Jing Jin
- School of Psychology, Shanghai University of Sport, Shanghai 200438, China
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Smalianchuk I, Gandhi NJ. Ventral premotor cortex encodes task relevant features during eye and head movements. Sci Rep 2022; 12:22093. [PMID: 36543870 PMCID: PMC9772313 DOI: 10.1038/s41598-022-26479-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
Visual exploration of the environment is achieved through gaze shifts or coordinated movements of the eyes and the head. The kinematics and contributions of each component can be decoupled to fit the context of the required behavior, such as redirecting the visual axis without moving the head or rotating the head without changing the line of sight. A neural controller of these effectors, therefore, must show code relating to multiple muscle groups, and it must also differentiate its code based on context. In this study we tested whether the ventral premotor cortex (PMv) in monkey exhibits a population code relating to various features of eye and head movements. We constructed three different behavioral tasks or contexts, each with four variables to explore whether PMv modulates its activity in accordance with these factors. We found that task related population code in PMv differentiates between all task related features and conclude that PMv carries information about task relevant features during eye and head movements. Furthermore, this code represents both lower-level (effector and movement direction) and higher-level (context) information.
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Affiliation(s)
- Ivan Smalianchuk
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Neeraj J Gandhi
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA.
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Rho G, Callara AL, Vanello N, Gentili C, Greco A, Scilingo EP. Odor valence modulates cortico-cortical interactions: a preliminary study using DCM for EEG. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:604-607. [PMID: 34891366 DOI: 10.1109/embc46164.2021.9629910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Olfaction and emotions share common networks in the brain. However, little is known on how the emotional content of odors modulate dynamically the cortico-cortical interactions within these networks. In this preliminary study, we investigated the effect of odor valence on effective connectivity through the use of Dynamic Causal Modeling (DCM). We recorded electroencephalographic (EEG) data from healthy subjects performing a passive odor task of odorants with different valence. Once defined a fully-connected a priori network comprising the pyriform cortex (PC), orbitofrontal cortex (OFC), and entorhinal cortex (EC), we tested the modulatory effect of odor valence on their causal interactions at the group level using the parametric empirical bayes (PEB) framework. Results show that both pleasant and the unpleasant odors have an inhibitory effect on the connection from EC to PC, whereas we did not observe any effect for the neutral odor. Moreover, the odor with positive valence has a stronger influence on connectivity dynamics compared to the negative odor. Although preliminary, our results suggest that odor valence can modulate brain connectivity.
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Increased prefrontal top-down control in older adults predicts motor performance and age-group association. Neuroimage 2021; 240:118383. [PMID: 34252525 DOI: 10.1016/j.neuroimage.2021.118383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/29/2021] [Accepted: 07/08/2021] [Indexed: 11/21/2022] Open
Abstract
Bimanual motor control declines during ageing, affecting the ability of older adults to maintain independence. An important underlying factor is cortical atrophy, particularly affecting frontal and parietal areas in older adults. As these regions and their interplay are highly involved in bimanual motor preparation, we investigated age-related connectivity changes between prefrontal and premotor areas of young and older adults during the preparatory phase of complex bimanual movements using high-density electroencephalography. Generative modelling showed that excitatory inter-hemispheric prefrontal to premotor coupling in older adults predicted age-group affiliation and was associated with poor motor-performance. In contrast, excitatory intra-hemispheric prefrontal to premotor coupling enabled older adults to maintain motor-performance at the cost of lower movement speed. Our results disentangle the complex interplay in the prefrontal-premotor network during movement preparation underlying reduced bimanual control and the well-known speed-accuracy trade-off seen in older adults.
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Beck MM, Spedden ME, Dietz MJ, Karabanov AN, Christensen MS, Lundbye-Jensen J. Cortical signatures of precision grip force control in children, adolescents, and adults. eLife 2021; 10:61018. [PMID: 34121656 PMCID: PMC8216716 DOI: 10.7554/elife.61018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 06/04/2021] [Indexed: 11/13/2022] Open
Abstract
Human dexterous motor control improves from childhood to adulthood, but little is known about the changes in cortico-cortical communication that support such ontogenetic refinement of motor skills. To investigate age-related differences in connectivity between cortical regions involved in dexterous control, we analyzed electroencephalographic data from 88 individuals (range 8-30 years) performing a visually guided precision grip task using dynamic causal modelling and parametric empirical Bayes. Our results demonstrate that bidirectional coupling in a canonical 'grasping network' is associated with precision grip performance across age groups. We further demonstrate greater backward coupling from higher-order to lower-order sensorimotor regions from late adolescence in addition to differential associations between connectivity strength in a premotor-prefrontal network and motor performance for different age groups. We interpret these findings as reflecting greater use of top-down and executive control processes with development. These results expand our understanding of the cortical mechanisms that support dexterous abilities through development.
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Affiliation(s)
- Mikkel Malling Beck
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | | | - Martin Jensen Dietz
- Center of Functionally Integrative Neuroscience, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Anke Ninija Karabanov
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark.,Danish Research Centre for Magnetic Resonance (DRCMR), Hvidovre Hospital, Hvidovre, Denmark
| | | | - Jesper Lundbye-Jensen
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark.,Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
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Takahashi R, Fujita K, Kobayashi Y, Ogawa T, Teranishi M, Kawamura M. Effect of muscle fatigue on brain activity in healthy individuals. Brain Res 2021; 1764:147469. [PMID: 33838129 DOI: 10.1016/j.brainres.2021.147469] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/23/2021] [Accepted: 04/04/2021] [Indexed: 11/20/2022]
Abstract
Fatigue is affected by both peripheral and central factors. However, the interrelationship between muscle fatigue and brain activity has not yet been clarified. This study aimed to clarify the effect of muscle fatigue due to sustained pinch movement on brain activity in healthy individuals using functional near-infrared spectroscopy (fNIRS). Ten healthy adults participated in the study. Pinch movement of isometric contraction was the task to be performed, and electromyogram of the first dorsal interosseous muscle and brain activity by fNIRS were measured in this period. The median power frequency (MdPF) was calculated as an index of muscle fatigue and the oxygen-Hb value in the bilateral premotor and motor areas was calculated as an index of brain activity. As a result, MdPF showed a significant decrease in the middle and later phases compared with that in the early phase (p < 0.05, p < 0.001, respectively) and a significant decrease in the later phase compared with that in the middle phase (p < 0.05). The oxygen-Hb values in the motor cortex were not significantly different between the analysis sections. The oxygen-Hb values in the premotor cortex was significantly increased in the later phase (p < 0.05) compared with that in the early phase. The premotor cortex was found to be specifically activated during muscle fatigue.
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Affiliation(s)
- Ryo Takahashi
- Department of Physical Therapy Rehabilitation, Fukui General Hospital, Fukui-city, Fukui, Japan.
| | - Kazuki Fujita
- Department of Rehabilitation, Faculty of Health Science, Fukui Health Science University, Fukui-city, Fukui, Japan
| | - Yasutaka Kobayashi
- Department of Rehabilitation, Faculty of Health Science, Fukui Health Science University, Fukui-city, Fukui, Japan
| | - Tomoki Ogawa
- Department of Physical Therapy Rehabilitation, Fukui General Hospital, Fukui-city, Fukui, Japan
| | - Masanobu Teranishi
- Department of Physical Therapy Rehabilitation, Fukui General Hospital, Fukui-city, Fukui, Japan
| | - Mimpei Kawamura
- Department of Medical and Social, Faculty of Health Science, Kyoto Koka Women's University, Japan
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