TY - THES AU - Bräm Farias, J. TI - Neuromuskuläre Kontrolle des M. soleus und M. tibialis anterior PY - 2023 SP - 64 UR - https://m2.mtmt.hu/api/publication/34714308 ID - 34714308 LA - German DB - MTMT ER - TY - THES AU - Federer, M. TI - Neuromuskuläre Kontrolle des m. soleus und m. tibialis anterior im Alter PY - 2023 SP - 74 UR - https://m2.mtmt.hu/api/publication/34714304 ID - 34714304 LA - German DB - MTMT ER - TY - JOUR AU - Skiadopoulos, Andreas AU - Famodimu, Grace O. AU - Solomon, Shammah K. AU - Agarwal, Parul AU - Harel, Noam Y. AU - Knikou, Maria TI - Priming locomotor training with transspinal stimulation in people with spinal cord injury: study protocol of a randomized clinical trial JF - TRIALS J2 - TRIALS VL - 24 PY - 2023 IS - 1 PG - 19 SN - 1745-6215 DO - 10.1186/s13063-023-07193-4 UR - https://m2.mtmt.hu/api/publication/33971112 ID - 33971112 AB - Background The seemingly simple tasks of standing and walking require continuous integration of complex spinal reflex circuits between descending motor commands and ascending sensory inputs. Spinal cord injury greatly impairs standing and walking ability, but both improve with locomotor training. However, even after multiple locomotor training sessions, abnormal muscle activity and coordination persist. Thus, locomotor training alone cannot fully optimize the neuronal plasticity required to strengthen the synapses connecting the brain, spinal cord, and local circuits and potentiate neuronal activity based on need. Transcutaneous spinal cord (transspinal) stimulation alters motoneuron excitability over multiple segments by bringing motoneurons closer to threshold, a prerequisite for effectively promoting spinal locomotor network neuromodulation and strengthening neural connectivity of the injured human spinal cord. Importantly, whether concurrent treatment with transspinal stimulation and locomotor training maximizes motor recovery after spinal cord injury is unknown. Methods Forty-five individuals with chronic spinal cord injury are receiving 40 sessions of robotic gait training primed with 30 Hz transspinal stimulation at the Thoracic 10 vertebral level. Participants are randomized to receive 30 min of active or sham transspinal stimulation during standing or active transspinal stimulation while supine followed by 30 min of robotic gait training. Over the course of locomotor training, the body weight support, treadmill speed, and leg guidance force are adjusted as needed for each participant based on absence of knee buckling during the stance phase and toe dragging during the swing phase. At baseline and after completion of all therapeutic sessions, neurophysiological recordings registering corticospinal and spinal neural excitability changes along with clinical assessment measures of standing and walking, and autonomic function via questionnaires regarding bowel, bladder, and sexual function are taken. Discussion The results of this mechanistic randomized clinical trial will demonstrate that tonic transspinal stimulation strengthens corticomotoneuronal connectivity and dynamic neuromodulation through posture-dependent corticospinal and spinal neuroplasticity. We anticipate that this mechanistic clinical trial will greatly impact clinical practice because, in real-world clinical settings, noninvasive transspinal stimulation can be more easily and widely implemented than invasive epidural stimulation. Additionally, by applying multiple interventions to accelerate motor recovery, we are employing a treatment regimen that reflects a true clinical approach. LA - English DB - MTMT ER - TY - JOUR AU - Hagoort, Iris AU - Hortobágyi, Tibor AU - Vuillerme, Nicolas AU - Lamoth, Claudine J. C. AU - Murgia, Alessio TI - Age- and muscle-specific reliability of muscle architecture measurements assessed by two-dimensional panoramic ultrasound JF - BIOMEDICAL ENGINEERING ONLINE J2 - BIOMED ENG ONLINE VL - 21 PY - 2022 IS - 1 PG - 19 SN - 1475-925X DO - 10.1186/s12938-021-00967-4 UR - https://m2.mtmt.hu/api/publication/32680478 ID - 32680478 N1 - Funding Agency and Grant Number: French National Research Agency [ANR-10-AIRT-05, ANR-15-IDEX-02] Funding text: This work was supported by the French National Research Agency in the framework of the Investissements d'avenir program (ANR-10-AIRT-05 and ANR-15-IDEX-02). The sponsors had no involvement in the review and approval of the manuscript for publication. This work forms part of a broader interdisciplinary project, GaitAlps. LA - English DB - MTMT ER - TY - THES AU - Meyer, S. TI - Die Rolle des primären Motorkortex in der Langzeit-Konsolidierung einer Gleichgewichtsaufgabe. Untersuchung der Interferenz von rTMS auf die Gleichgewichts-performance und die kortikalen Adaptionen TS - Untersuchung der Interferenz von rTMS auf die Gleichgewichts-performance und die kortikalen Adaptionen PY - 2022 SP - 75 UR - https://m2.mtmt.hu/api/publication/34714318 ID - 34714318 LA - German DB - MTMT ER - TY - JOUR AU - Bakker, Lisanne B.M. AU - Nandi, Tulika AU - Lamoth, Claudine J.C. AU - Hortobágyi, Tibor TI - Task specificity and neural adaptations after balance learning in young adults JF - HUMAN MOVEMENT SCIENCE J2 - HUM MOVEMENT SCI VL - 78 PY - 2021 PG - 10 SN - 0167-9457 DO - 10.1016/j.humov.2021.102833 UR - https://m2.mtmt.hu/api/publication/32084951 ID - 32084951 LA - English DB - MTMT ER - TY - JOUR AU - Lauber, Benedikt AU - Gollhofer, Albert AU - Taube, Wolfgang TI - What to train first: Balance or explosive strength? Impact on performance and intracortical inhibition JF - SCANDINAVIAN JOURNAL OF MEDICINE & SCIENCE IN SPORTS J2 - SCAND J MED SCI SPOR VL - 31 PY - 2021 IS - 6 SP - 1301 EP - 1312 PG - 12 SN - 0905-7188 DO - 10.1111/sms.13939 UR - https://m2.mtmt.hu/api/publication/32339829 ID - 32339829 AB - Explosive strength and balance training are commonly applied to enhance explosive strength and balance performance. Even though both training methods are frequently implemented, ordering effects have largely been neglected. Therefore, the present study aimed to investigate ordering effects of balance and explosive strength training on explosive strength and balance performance as well as changes in short-interval intracortical inhibition (SICI). Two groups of subjects either participated in 4 weeks of balance training followed by 4 weeks of explosive strength training (BT-ET) or vice versa (ET-BT). Before, after 4 and 8 weeks, balance performance, as well as explosive strength, was tested. Additionally, SICI was tested during rest as well as during balance perturbations and explosive contractions. The results show a training specific increase in performance with an increase in balance control followed by an increase in explosive strength in the BT-ET, while the ET-BT increased its balance and explosive strength in the opposite order. There were no significant ordering effects. Both groups showed a significant decrease in SICI during the explosive contractions after the eight weeks of training. When SICI was tested during the balance perturbations, SICI initially increased after the first 4 weeks of training but returned to baseline until the end of the eight weeks. It is suggested that the decrease in SICI with prolonged training might show a disengagement of the motor cortex during the balance task. During the explosive contractions, the low SICI levels are beneficial to provide the necessary level of excitatory cortical drive. LA - English DB - MTMT ER - TY - THES AU - Meyer, Anne TI - Influence de la stimulation magnétique transcrânienne répétée du cortex moteur primaire sur une tâche d’équilibre et le réflexe d’Hoffmann PY - 2021 SP - 59 UR - https://m2.mtmt.hu/api/publication/34714296 ID - 34714296 LA - French DB - MTMT ER - TY - JOUR AU - Mouthon, A. AU - Ruffieux, J. AU - Taube, W. TI - Modulation of intracortical inhibition during physically performed and mentally simulated balance tasks JF - EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY J2 - EUR J APPL PHYSIOL VL - 121 PY - 2021 IS - 5 SP - 1379 EP - 1388 PG - 10 SN - 1439-6319 DO - 10.1007/s00421-020-04577-1 UR - https://m2.mtmt.hu/api/publication/32339828 ID - 32339828 AB - Purpose Action observation (AO) during motor imagery (MI), so-called AO + MI, has been proposed as a new form of non-physical training, but the neural mechanisms involved remains largely unknown. Therefore, this study aimed to explore whether there were similarities in the modulation of short-interval intracortical inhibition (SICI) during execution and mental simulation of postural tasks, and if there was a difference in modulation of SICI between AO + MI and AO alone. Method 21 young adults (mean +/- SD = 24 +/- 6.3 years) were asked to either passively observe (AO) or imagine while observing (AO + MI) or physically perform a stable and an unstable standing task, while motor evoked potentials and SICI were assessed in the soleus muscle. Result SICI results showed a modulation by condition (F-2,F-40 = 6.42, p = 0.009) with less SICI in the execution condition compared to the AO + MI (p = 0.009) and AO (p = 0.002) condition. Moreover, switching from the stable to the unstable stance condition reduced significantly SICI (F-1,F-20 = 8.34, p = 0.009) during both, physically performed (- 38.5%; p = 0.03) and mentally simulated balance (- 10%, p < 0.001, AO + MI and AO taken together). Conclusion The data demonstrate that SICI is reduced when switching from a stable to a more unstable standing task during both real task execution and mental simulation. Therefore, our results strengthen and further support the existence of similarities between executed and mentally simulated actions by showing that not only corticospinal excitability is similarly modulated but also SICI. This proposes that the activity of the inhibitory cortical network during mental simulation of balance tasks resembles the one during physical postural task execution. LA - English DB - MTMT ER - TY - JOUR AU - Pion, Charlotte H. AU - St-Pierre Bolduc, Melissa AU - Miranda, Zoe AU - MacMahon, Maureen AU - Barthelemy, Dorothy TI - Alteration of H-reflex amplitude modulation is a marker of impaired postural responses in individuals with incomplete spinal cord injury JF - EXPERIMENTAL BRAIN RESEARCH J2 - EXP BRAIN RES VL - 239 PY - 2021 IS - 6 SP - 1779 EP - 1794 PG - 16 SN - 0014-4819 DO - 10.1007/s00221-021-06081-0 UR - https://m2.mtmt.hu/api/publication/32339827 ID - 32339827 AB - Individuals with incomplete spinal cord injury (iSCI) show altered postural reactions leading to increased risk of falls. To investigate neural correlates underlying this deficit, we assessed the modulation pattern of the Soleus H-reflex in iSCI individuals following unexpected perturbations of a base of support. Ten men with iSCI (AIS D) and 8 age-matched controls (CTRL) stood on a force-platform randomly tilted forward or backward. The center of pressure (CoP) excursion, 95% confidence ellipse area and electromyographic (EMG) activity of the Soleus (SOL) and Tibialis Anterior (TA) muscles were analyzed. SOL H-reflex amplitude was assessed by stimulating the tibial nerve prior to and at 100, 150 and 200 ms following perturbation onset. Although SOL and TA short-latency EMG responses were comparable in both groups, long-latency EMG responses occurred later in the iSCI group for both directions: during backward tilt, a decrease in H-reflex amplitude was observed at all stimulus timings post-tilt in CTRL, but only at 200 ms in iSCI. The decrease in H-reflex amplitude was smaller in iSCI participants. During forward tilt, an increase in H-reflex amplitude was observed at 150 and 200 ms in the CTRL group, but no increase was observed in the iSCI group. Decreased and delayed SOL H-reflex amplitude modulation in the iSCI group accompanied impaired balance control as assessed clinically with the Berg Balance Scale and biomechanically through CoP displacement. Overall, delayed and reduced spinal reflex processing may contribute to impaired balance control in people with iSCI. LA - English DB - MTMT ER - TY - JOUR AU - Alizadehsaravi, Leila AU - Bruijn, Sjoerd M. AU - Maas, Huub AU - van Dieen, Jaap H. TI - Modulation of soleus muscle H-reflexes and ankle muscle co-contraction with surface compliance during unipedal balancing in young and older adults JF - EXPERIMENTAL BRAIN RESEARCH J2 - EXP BRAIN RES VL - 238 PY - 2020 IS - 6 SP - 1371 EP - 1383 PG - 13 SN - 0014-4819 DO - 10.1007/s00221-020-05784-0 UR - https://m2.mtmt.hu/api/publication/31482158 ID - 31482158 AB - This study aimed to assess modulation of lower leg muscle reflex excitability and co-contraction during unipedal balancing on compliant surfaces in young and older adults. Twenty healthy adults (ten aged 18-30 years and ten aged 65-80 years) were recruited. Soleus muscle H-reflexes were elicited by electrical stimulation of the tibial nerve, while participants stood unipedally on a robot-controlled balance platform, simulating different levels of surface compliance. In addition, electromyographic data (EMG) of soleus (SOL), tibialis anterior (TA), and peroneus longus (PL) and full-body 3D kinematic data were collected. The mean absolute center of mass velocity was determined as a measure of balance performance. Soleus H-reflex data were analyzed in terms of the amplitude related to the M wave and the background EMG activity 100 ms prior to the stimulation. The relative duration of co-contraction was calculated for soleus and tibialis anterior, as well as for peroneus longus and tibialis anterior. Center of mass velocity was significantly higher in older adults compared to young adults ( p < 0.001) and increased with increasing surface compliance in both groups ( p < 0.001). The soleus H-reflex gain decreased with surface compliance in young adults ( p = 0.003), while co-contraction increased ( pSOL, TA = 0.003 and pPL, TA < 0.001). Older adults did not show such modulations, but showed overall lower H-reflex gains ( p < 0.001) and higher co-contraction than young adults ( pSOL, TA < 0.001 and pPL, TA = 0.002). These results suggest an overall shift in balance control from the spinal level to supraspinal levels in older adults, which also occurred in young adults when balancing at more compliant surfaces. LA - English DB - MTMT ER - TY - JOUR AU - Hiraoka, Koichi AU - Gonno, Shintaro AU - Inomoto, Ryota TI - The Left Posterior Parietal Cortex Contributes to the Selection Process for the Initial Swing Leg in Gait Initiation JF - BRAIN SCIENCES J2 - BRAIN SCI VL - 10 PY - 2020 IS - 5 PG - 16 SN - 2076-3425 DO - 10.3390/brainsci10050317 UR - https://m2.mtmt.hu/api/publication/31482159 ID - 31482159 AB - The present study examined whether the left posterior parietal cortex contributes to the selection process for the initial swing leg in gait initiation. Healthy humans initiated the gait in response to an auditory start cue. Transcranial magnetic stimulation (TMS) was given over P3, P4, F3 or F4 simultaneously, with the auditory start cue, in the on-TMS condition. A coil was placed over one of the four TMS sites, but TMS was not given in the off-TMS condition. The probability of right leg selection in the on-TMS condition was significantly lower than in the off-TMS condition when the coil was placed over P3, indicating that the left posterior parietal cortex contributes to the selection process of the initial swing leg of gait initiation. The latency of the anticipatory postural adjustment for gait initiation with the left leg was shortened by TMS over F4 or P4, but with the right leg was shortened by TMS over P3 or P4. Thus, the cortical process affecting the time taken to execute the motor process of gait initiation with the right leg may be related to the selection process of the initial swing leg of gait initiation. LA - English DB - MTMT ER - TY - JOUR AU - Taube, Wolfgang AU - Gollhofer, Albert AU - Lauber, Benedikt TI - Training-, muscle- and task-specific up- and downregulation of cortical inhibitory processes JF - EUROPEAN JOURNAL OF NEUROSCIENCE J2 - EUR J NEUROSCI VL - 51 PY - 2020 IS - 6 SP - 1428 EP - 1440 PG - 13 SN - 0953-816X DO - 10.1111/ejn.14538 UR - https://m2.mtmt.hu/api/publication/31482160 ID - 31482160 AB - Motor cortical contribution was shown to be important for balance control and for ballistic types of movements. However, little is known about the role of cortical inhibitory mechanisms and even less about long(er)-term adaptations of these inhibitory processes. Therefore, the aim of the present study was to investigate the role of intracortical inhibition before and after four weeks of explosive or balance training. Two groups of subjects participated for four weeks either in an explosive training programme of the plantar flexor muscles or in a balance training programme on unstable devices. Adaptations in short-interval intracortical inhibition (SICI) were assessed by applying paired-pulse TMS to the soleus muscle during dynamic plantar flexions, balance perturbations and at rest. Furthermore, SICI was assessed for the untrained tibialis anterior muscle. The results show task-, muscle- and group-specific adaptations in SICI after the training (p = .021) with significantly increased SICI after balance training in the balance task and decreased SICI after explosive training in the ballistic task. The training also caused task- and group-specific behavioural adaptations indicated by improved balance performance after balance training and increased ballistic performance after explosive training. There were no changes in SICI when measured at rest or in the untrained tibialis anterior muscle. This study shows that long(er)-term training improves the ability to modulate cortical inhibitory processes in a task- and muscle-specific manner. LA - English DB - MTMT ER - TY - THES AU - Collomb, C. TI - L’entrainement de l’équilibre à long terme induit une amélioration du contrôle postural liée à des modifications dans la modulation de l’inhibition intra-corticale chez les seniors et les jeunes adultes PY - 2019 SP - 52 UR - https://m2.mtmt.hu/api/publication/34714322 ID - 34714322 LA - French DB - MTMT ER - TY - JOUR AU - Kim, Kyung-Min AU - Kim, Joo-Sung AU - Cruz-Diaz, David AU - Ryu, Seungho AU - Kang, Minsoo AU - Taube, Wolfgang TI - Changes in Spinal and Corticospinal Excitability in Patients with Chronic Ankle Instability: A Systematic Review with Meta-Analysis JF - JOURNAL OF CLINICAL MEDICINE J2 - J CLIN MED VL - 8 PY - 2019 IS - 7 PG - 24 SN - 2077-0383 DO - 10.3390/jcm8071037 UR - https://m2.mtmt.hu/api/publication/31223451 ID - 31223451 AB - The objective of this systematic review with meta-analysis was to determine alterations in spinal and corticospinal excitability of ankle muscles in patients with chronic ankle instability (CAI) compared to uninjured controls. Independent researchers performed comprehensive literature searches of electronic databases and included studies that compared groups with and without CAI and investigated neural excitability with Hoffmann reflex (H-reflex) and/or transcranial magnetic stimulation (TMS). A fixed-effect meta-analysis was conducted to determine group differences for (1) soleus and fibularis maximal H-reflex (Hmax)/maximal M-wave (Mmax)-ratios, and (2) soleus and fibularis longus cortical motor thresholds (CMTs). Seventeen studies were included in the current meta-analysis. They showed that the Hmax/Mmax-ratios of the soleus and the fibularis longus in the CAI group were significantly lower than those in the uninjured control group (soleus: d = -0.41, p < 0.001; fibularis longus: d = -0.27, p = 0.04). There was no evidence for changes in the CMT. This systematic review is the first to demonstrate evidence that patients with CAI present decreased spinal reflex excitability in the soleus and fibularis longus. However, there is no evidence of changes in supraspinal excitability when considering only the CMT. The latter result needs to be interpreted with caution as all except one study demonstrate some changes at the supraspinal level with CAI. LA - English DB - MTMT ER - TY - JOUR AU - Miranda, Zoe AU - Pham, Annie AU - Elgbeili, Guillaume AU - Barthelemy, Dorothy TI - H-reflex modulation preceding changes in soleus EMG activity during balance perturbation JF - EXPERIMENTAL BRAIN RESEARCH J2 - EXP BRAIN RES VL - 237 PY - 2019 IS - 3 SP - 777 EP - 791 PG - 15 SN - 0014-4819 DO - 10.1007/s00221-018-5459-0 UR - https://m2.mtmt.hu/api/publication/31223453 ID - 31223453 AB - When balance is compromised, postural strategies are induced to quickly recover from the perturbation. However, neuronal mechanisms underlying these strategies are not fully understood. Here, we assessed the amplitude of the soleus (SOL) H-reflex during forward and backward tilts of the support surface during standing (n=15 healthy participants). Electrical stimulation of the tibial nerve was applied randomly before platform tilt (control) and 0, 25, 50, 75, 100 or 200ms after tilt onset. During backward tilt, a significant decrease in H-reflex amplitude was observed at 75, 100 and 200ms. The onset of the decreased H-reflex amplitude significantly preceded the onset of the SOL EMG decrease (latency: 144 +/- 16ms). During forward tilt, the amplitude of the H-reflex increased at 100 and 200ms after tilt onset. The onset of H-reflex increase did not occur significantly earlier than the onset of the SOL EMG increase (127 +/- 5ms). An important inter-subject variability was observed for the onset of H-reflex modulation with respect to EMG response for each direction of tilt, but this variability could not be explained by the subject's height. Taken together, the results establish the time course of change in SOL H-reflex excitability and its relation to the increase and decrease in SOL EMG activity during forward and backward tilts. The data presented here also suggest that balance mechanisms may differ between forward and backward tilts. LA - English DB - MTMT ER - TY - JOUR AU - Mouthon, A. AU - Taube, W. TI - Intracortical Inhibition Increases during Postural Task Execution in Response to Balance Training JF - NEUROSCIENCE J2 - NEUROSCIENCE VL - 401 PY - 2019 SP - 35 EP - 42 PG - 8 SN - 0306-4522 DO - 10.1016/j.neuroscience.2019.01.007 UR - https://m2.mtmt.hu/api/publication/31223454 ID - 31223454 AB - Intracortical inhibitory modulation seems crucial for an intact motor control and motor learning. However, the influence of long(er) term training on short-interval intracortical inhibition (SICI) is scarcely investigated. With respect to balance, it was previously shown that with increasing postural task difficulty, SICI decreased but the effect of balance training (BT) is unknown. The present study tested whether improvements in postural control due to BT are accompanied by changes in SICI. SICI was measured in the tibialis anterior by applying paired-pulse magnetic stimuli to the motor cortex in a BT group (n = 13) training 2 weeks on an unstable platform and a control (CON) group (n = 13) while performing three progressively demanding postural tasks: stable stance ('Stable'), standing on a movable platform partly secured with elastic straps ('Straps') or freely moving ('Free'). The BT group improved postural control significantly more than the CON-group ('Free' condition: +80% vs. + 21%; p < 0.001). For SICI, there was a main effect of POSTURAL TASK (F-2, (48) = 24.6; p < 0.001) with decreasing SICI when task difficulty increased and a TIME x GROUP interaction (F-1, (24) = 5.9; p = 0.02) caused by significantly enhanced SICI in the BT group in all three postural tasks after the training. The increases in SICI were significantly correlated with improvements in balance performance (r = 0.56; p = 0.047). The present study confirms previous findings of task-specific modulation of SICI when balancing. More importantly, training was shown to increase SICI and this increase was correlated with changes in balance performance. Thus, changes in SICI seem to be involved not only for the control but also when adapting upright posture with training. (C) 2019 The Author(s). Published by Elsevier Ltd on behalf of IBRO. LA - English DB - MTMT ER - TY - JOUR AU - Nanclia, Tulika AU - Lewthwaite, Rebecca AU - Fisher, Beth E. AU - Salem, George J. TI - Balance confidence scale: Preliminary validity, reliability, and relation to neural excitability in young adults JF - PSYCHOLOGY OF SPORT AND EXERCISE J2 - PSYCHOL SPORT EXERC VL - 43 PY - 2019 SP - 301 EP - 310 PG - 10 SN - 1469-0292 DO - 10.1016/j.psychsport.2019.04.004 UR - https://m2.mtmt.hu/api/publication/31223452 ID - 31223452 AB - Balance confidence may reflect and affect balance performance, and this effect may be mediated by neural inputs to muscles. Available balance confidence scales are designed for older adults and individuals with pathological conditions. To eliminate ceiling effects for young adults and to enable the study of neural excitability in relation to confidence relevant to balance, we developed a Balance Confidence Scale (BCS), comprised of items depicting single limb stance conditions of varying difficulty. Motor cortical excitability was measured using transcranial magnetic stimulation (TMS). Preliminary construct validity was examined relative to balance performance, perceived steadiness, and previous physical activity in 20 young adults (25.7 +/- 4.2 years; 11 females). The scale showed good internal consistency (Cronbach's a = 0.81) and good test-retest reliability (ICC2,1 = 0.84) in a separate sample of 21 young adults (23.8 +/- 4.6 years; 11 females). Balance confidence ranged from 34 to 79.6% in the validity sample. Confidence was correlated with performance indexed using center of pressure velocity (r = 0.62, p = 0.01) and area (r = 0.49, p = 0.04), in a relatively difficult standing condition with one leg positioned on an unstable spring. Perceived steadiness and overall physical activity were not correlated with confidence; however, participants with higher confidence scores reported greater experience with balance related activities. Finally, confidence was related to indices of motor cortical excitability. The Balance Confidence Scale has sound preliminary validity and reliability and holds promise for the study of neural processes mediating social-cognitive influences on balance performance. LA - English DB - MTMT ER - TY - THES AU - Nandi, T. TI - Neural control of balance in increasingly difficult standing tasks PY - 2019 UR - https://m2.mtmt.hu/api/publication/34714344 ID - 34714344 LA - English DB - MTMT ER - TY - JOUR AU - Nandi, Tulika AU - Hortobágyi, Tibor AU - van Keeken, Helco G. AU - Salem, George J. AU - Lamoth, Claudine J. C. TI - Standing task difficulty related increase in agonist-agonist and agonist-antagonist common inputs are driven by corticospinal and subcortical inputs respectively JF - SCIENTIFIC REPORTS J2 - SCI REP VL - 9 PY - 2019 PG - 12 SN - 2045-2322 DO - 10.1038/s41598-019-39197-z UR - https://m2.mtmt.hu/api/publication/31223450 ID - 31223450 AB - In standing, coordinated activation of lower extremity muscles can be simplified by common neural inputs to muscles comprising a functional synergy. We examined the effect of task difficulty on common inputs to agonist-agonist (AG-AG) pairs supporting direction specific reciprocal muscle control and agonist-antagonist (AG-ANT) pairs supporting stiffness control. Since excessive stiffness is energetically costly and limits the flexibility of responses to perturbations, compared to AG-ANT, we expected greater AG-AG common inputs and a larger increase with increasing task difficulty. We used coherence analysis to examine common inputs in three frequency ranges which reflect subcortical/spinal (0-5 and 6-15 Hz) and corticospinal inputs (6-15 and 16-40 Hz). Coherence was indeed higher in AG-AG compared to AG-ANT muscles in all three frequency bands, indicating a predilection for functional synergies supporting reciprocal rather than stiffness control. Coherence increased with increasing task difficulty, only in AG-ANT muscles in the low frequency band (0-5 Hz), reflecting subcortical inputs and only in AG-AG group in the high frequency band (16-40 Hz), reflecting corticospinal inputs. Therefore, common neural inputs to both AG-AG and AG-ANT muscles increase with difficulty but are likely driven by different sources of input to spinal alpha motor neurons. LA - English DB - MTMT ER - TY - JOUR AU - Portaro, Simona AU - Naro, Antonino AU - Cacciola, Alberto AU - Marra, Angela AU - Quartarone, Angelo AU - Milardi, Demetrio AU - Calabro, Rocco Salvatore TI - Adult-Onset Walking-Upstairs Dystonia JF - JOURNAL OF CLINICAL NEUROLOGY J2 - J CLIN NEUROL VL - 15 PY - 2019 IS - 1 SP - 122 EP - 124 PG - 3 SN - 1738-6586 DO - 10.3988/jcn.2019.15.1.122 UR - https://m2.mtmt.hu/api/publication/31223455 ID - 31223455 LA - English DB - MTMT ER - TY - THES AU - Schafer, C. TI - Kortikale inhibitorische Kontrolle des Musculus tibialis anterior bei ballistischen Kontraktionen PY - 2019 SP - 52 UR - https://m2.mtmt.hu/api/publication/34714333 ID - 34714333 LA - German DB - MTMT ER - TY - JOUR AU - Kesar, Trisha M. AU - Stinear, James W. AU - Wolf, Steven L. TI - The use of transcranial magnetic stimulation to evaluate cortical excitability of lower limb musculature: Challenges and opportunities JF - RESTORATIVE NEUROLOGY AND NEUROSCIENCE J2 - RESTOR NEUROL NEUROS VL - 36 PY - 2018 IS - 3 SP - 333 EP - 348 PG - 16 SN - 0922-6028 DO - 10.3233/RNN-170801 UR - https://m2.mtmt.hu/api/publication/31223459 ID - 31223459 AB - Neuroplasticity is a fundamental yet relatively unexplored process that can impact rehabilitation of lower extremity (LE) movements. Transcranial magnetic stimulation (TMS) has gained widespread application as a non-invasive brain stimulation technique for evaluating neuroplasticity of the corticospinal pathway. However, a majority of TMS studies have been performed on hand muscles, with a paucity of TMS investigations focused on LE muscles. This perspective review paper proposes that there are unique methodological challenges associated with using TMS to evaluate corticospinal excitability of lower limb muscles. The challenges include: (1) the deeper location of the LE motor homunculus; (2) difficulty with targeting individual LE muscles during TMS; and (3) differences in corticospinal circuity controlling upper and lower limb muscles. We encourage future investigations that modify traditional methodological approaches to help address these challenges. Systematic TMS investigations are needed to determine the extent of overlap in corticomotor maps for different LE muscles. A simple, yet informative methodological solution involves simultaneous recordings from multiple LE muscles, which will provide the added benefit of observing how other relevant muscles co-vary in their responses during targeted TMS assessment directed toward a specific muscle. Furthermore, conventionally used TMS methods (e.g., determination of hot spot location and motor threshold) may need to be modified for TMS studies involving LE muscles. Additional investigations are necessary to determine the influence of testing posture as well as activation state of adjacent and distant LE muscles on TMS-elicited responses. An understanding of these challenges and solutions specific to LE TMS will improve the ability of neurorehabilitation clinicians to interpret TMS literature, and forge novel future directions for neuroscience research focused on elucidating neuroplasticity processes underlying locomotion and gait training. LA - English DB - MTMT ER - TY - JOUR AU - Lauber, Benedikt AU - Gollhofer, Albert AU - Taube, Wolfgang TI - Differences in motor cortical control of the soleus and tibialis anterior JF - JOURNAL OF EXPERIMENTAL BIOLOGY J2 - J EXP BIOL VL - 221 PY - 2018 IS - 20 PG - 8 SN - 0022-0949 DO - 10.1242/jeb.174680 UR - https://m2.mtmt.hu/api/publication/31223456 ID - 31223456 AB - The tibialis anterior (TA) and the soleus (SOL) are ankle joint muscles with functionally very different tasks. Thus, differences in motor cortical control between the TA and the SOL have been debated. This study compared the activity of the primary motor cortex during dynamic plantarflexions and dorsiflexions and compared this with measures obtained during rest. Single- and paired-pulse transcranial magnetic stimulations known as short-interval intracortical inhibition (SICI) were applied to the cortical representation of either the SOL or the TA muscle. The results show that the range of SICI from rest to activity is significantly greater in the TA than in the SOL. Furthermore, when the TA acts as the agonist during dorsiflexions of the ankle, SICI is almost absent (2.9%). When acting as the antagonist during plantarflexions, intracortical inhibition is significantly increased (28.7%). This taskspecific modulation is far less pronounced in the SOL, which displayed higher levels of SICI when acting as the agonist (10.9%) during plantarflexion, but there was no significant inhibition (6.5%) as the antagonist during dorsiflexion. Furthermore. the cortical silent period (CSP) during plantarflexions was significantly longer in the SOL than in the TA during dorsiflexions, accompanied by a greater corticospinal excitability in the TA. Thus, cortical control considerably differs between the SOL and the TA in a way that inhibitory cortical control (SICI and CSP) of the TA is task-specifically adapted in a broader range of movements, whereas inhibition in the SOL muscle is less specific and more limited in its magnitude of modulation. LA - English DB - MTMT ER - TY - JOUR AU - Mouthon, A. AU - Ruffieux, J. AU - Mouthon, M. AU - Hoogewoud, H. -M. AU - Annoni, J. -M. AU - Taube, W. TI - Age-Related Differences in Cortical and Subcortical Activities during Observation and Motor Imagery of Dynamic Postural Tasks: An fMRI Study JF - NEURAL PLASTICITY J2 - NEURAL PLAST PY - 2018 PG - 12 SN - 2090-5904 DO - 10.1155/2018/1598178 UR - https://m2.mtmt.hu/api/publication/31223460 ID - 31223460 AB - Age-related changes in brain activation other than in the primary motor cortex are not well known with respect to dynamic balance control. Therefore, the current study aimed to explore age-related differences in the control of static and dynamic postural tasks using fMRI during mental simulation of balance tasks. For this purpose, 16 elderly (72 +/- 5 years) and 16 young adults (27 +/- 5 years) were asked to mentally simulate a static and a dynamic balance task by motor imagery (MI), action observation (AO), or the combination of AO and MI (AO + MI). Age-related differences were detected in the form of larger brain activations in elderly compared to young participants, especially in the challenging dynamic task when applying AO+ MI. Interestingly, when MI (no visual input) was contrasted to AO (visual input), elderly participants revealed deactivation of subcortical areas. The finding that the elderly demonstrated overactivation in mostly cortical areas in challenging postural conditions with visual input (AO + MI and AO) but deactivation in subcortical areas during MI (no vision) may indicate that elderly individuals allocate more cortical resources to the internal representation of dynamic postural tasks. Furthermore, it might be assumed that they depend more strongly on visual input to activate subcortical internal representations. LA - English DB - MTMT ER - TY - JOUR AU - Nandi, Tulika AU - Fisher, Beth E. AU - Hortobágyi, Tibor AU - Salem, George J. TI - Increasing mediolateral standing sway is associated with increasing corticospinal excitability, and decreasing M1 inhibition and facilitation JF - GAIT & POSTURE J2 - GAIT POSTURE VL - 60 PY - 2018 SP - 135 EP - 140 PG - 6 SN - 0966-6362 DO - 10.1016/j.gaitpost.2017.11.021 UR - https://m2.mtmt.hu/api/publication/31223461 ID - 31223461 AB - In standing, corticospinal excitability increases and primary motor cortex (M1) inhibition decreases in response to anterior posterior or direction unspecific manipulations that increase task difficulty. However, mediolateral (ML) sway control requires greater active neural involvement. Therefore, the primary purpose of this study was to determine the pattern of change in neural excitability when ML postural task difficulty is manipulated and to test whether the neural excitability is proportional to ML sway magnitude across conditions. Tibialis anterior corticospinal excitability was quantified using motor evoked potential (MEP) and postural sway was indexed using ML center of pressure (COP) velocity. Additionally, we examined inhibition and facilitation processes in the primary motor cortex using the paired pulse short interval intracortical inhibition (SICI) and intracortical facilitation (ICF) techniques respectively. Measurements were repeated in four conditions with quiet stance as a control. Differences between conditions were tested using one-way repeated measures ANOVAs, on log transformed data. Associations were quantified using Spearman's Rank Correlation Coefficient. There was a significant main effect of condition on all the neural excitability measures with MEP (p < 0.001) being highest in the most difficult condition, and SICI (p = 0.01), ICF (p < 0.001) being lowest in the most difficult condition. Increasing ML COP velocity was significantly associated with increasing MEP amplitude (r = 0.68, p < 0.001), but decreasing SICI (r = 0.24, p = 0.03) and ICF (r = -0.54, p < 0.001). Our results show that both corticospinal and M1 excitability in standing are scaled in proportion to ML task difficulty. LA - English DB - MTMT ER - TY - JOUR AU - Nandi, Tulika AU - Lamoth, Claudine J. C. AU - van Keeken, Helco G. AU - Bakker, Lisanne B. M. AU - Kok, Iris AU - Salem, George J. AU - Fisher, Beth E. AU - Hortobágyi, Tibor TI - In Standing, Corticospinal Excitability Is Proportional to COP Velocity Whereas M1 Excitability Is Participant-Specific JF - FRONTIERS IN HUMAN NEUROSCIENCE J2 - FRONT HUM NEUROSCI VL - 12 PY - 2018 PG - 8 SN - 1662-5161 DO - 10.3389/fnhum.2018.00303 UR - https://m2.mtmt.hu/api/publication/31223458 ID - 31223458 AB - Reductions in the base of support (BOS) make standing difficult and require adjustments in the neural control of sway. In healthy young adults, we determined the effects of reductions in mediolateral (ML) BOS on peroneus longus (PL) motor evoked potential (MEP), intracortical facilitation (ICF), short interval intracortical inhibition (SICI) and long interval intracortical inhibition (LICI) using transcranial magnetic stimulation (TMS). We also examined whether participant-specific neural excitability influences the responses to increasing standing difficulty. Repeated measures ANOVA revealed that with increasing standing difficulty MEP size increased, SICI decreased (both p < 0.05) and ICF trended to decrease (p = 0.07). LICI decreased only in a sub-set of participants, demonstrating atypical facilitation Spearman's Rank Correlation showed a relationship of rho = 0.50 (p = 0.001) between MEP size and ML center of pressure (COP) velocity. Measures of M1 excitability did not correlate with COP velocity. LICI and ICF measured in the control task correlated with changes in LICI and ICF, i.e., the magnitude of response to increasing standing difficulty. Therefore, corticospinal excitability as measured by MEP size contributes to ML sway control while cortical facilitation and inhibition are likely involved in other aspects of sway control while standing. Additionally, neural excitability in standing is determined by an interaction between task difficulty and participant-specific neural excitability. LA - English DB - MTMT ER - TY - JOUR AU - Tokuno, Craig D. AU - Keller, Martin AU - Carpenter, Mark G. AU - Marquez, Gonzalo AU - Taube, Wolfgang TI - Alterations in the cortical control of standing posture during varying levels of postural threat and task difficulty JF - JOURNAL OF NEUROPHYSIOLOGY J2 - J NEUROPHYSIOL VL - 120 PY - 2018 IS - 3 SP - 1010 EP - 1016 PG - 7 SN - 0022-3077 DO - 10.1152/jn.00709.2017 UR - https://m2.mtmt.hu/api/publication/31223457 ID - 31223457 AB - Cortical excitability increases during the performance of more difficult postural tasks. However, it is possible that changes in postural threat associated with more difficult-tasks may in themselves lead to alterations in the neural strategies underlying postural control. Therefore, the purpose of this study was to examine whether changes in postural threat are responsible for the alterations in corticospinal excitability and short-interval intracortical inhibition (SICI) that occur with increasing postural task difficulty. Fourteen adults completed three postural tasks (supported standing, free standing, or standing on an unstable board) at two surface heights (ground level or 3 m above ground). Single- and paired-pulse magnetic stimuli were applied to the motor cortex to compare soleus (SOL) and tibialis anterior (TA) test motor-evoked potentials (MEPs) and SICI between conditions. SOL and TA test MEPs increased from 0.35 +/- 0.29 to 0.82 +/- 0.41 mV (SOL) and from (1.64 +/- 0.51 to 1.96 +/- 1.45 mV (TA), respectively. whereas SKI decreased from 52.4 +/- 17.2% to 39.6 +/- 15.4% (SOL) and from 71.3 +/- 17.7% to 50.3 +/- 19.9% (TA) with increasing task difficulty. In contrast to the effects of task difficulty, only SOL test MEPs were smaller when participants stood at high (0.49 +/- 0.29 mV) compared with low height (0.61 +/- 0.40 mV). Because the presence of postural threat did not lead to any additional changes in the excitability of the motor corticospinal pathway and intracortical inhibition with increasing task difficulty, it seems unlikely that alterations in perceived threat are primarily responsible for the neurophysiological changes that are observed with increasing postural task difficulty.NEW & NOTEWORTHY We examined how task difficulty and postural threat influence the cortical control of posture. Results indicated that the motor corticospinal pathway and intracortical inhibition were modulated more by task difficulty than postural threat. Furthermore, because the presence of postural threat during the performance various postural tasks did not lead to summative changes in motor-evoked potentials, alterations in perceived threat are not responsible for the neurophysiological changes that occur with increasing postural task difficulty. LA - English DB - MTMT ER - TY - CHAP AU - Papegaaij, Selma AU - Hortobágyi, Tibor ED - Vitório, Rodrigo ED - Barbieri, Fabio Augusto TI - Age-Related Changes in the Neural Control of Standing Balance T2 - Locomotion and Posture in Older Adults PB - Springer Netherlands SN - 9783319489797 PY - 2017 SP - 427 EP - 444 PG - 18 DO - 10.1007/978-3-319-48980-3_27 UR - https://m2.mtmt.hu/api/publication/32667108 ID - 32667108 LA - English DB - MTMT ER - TY - THES AU - Udry, C. TI - Les mécanismes d'inhibition intracorticale diffèrent-ils entre les jeunes et les seniors lors d'exercices d'équilibre dynamique? PY - 2017 SP - 50 UR - https://m2.mtmt.hu/api/publication/34714359 ID - 34714359 LA - French DB - MTMT ER - TY - JOUR AU - Walchli, Michael AU - Tokuno, Craig D. AU - Ruffieux, Jan AU - Keller, Martin AU - Taube, Wolfgang TI - PREPARATORY CORTICAL AND SPINAL SETTINGS TO COUNTERACT ANTICIPATED AND NON-ANTICIPATED PERTURBATIONS JF - NEUROSCIENCE J2 - NEUROSCIENCE VL - 365 PY - 2017 SP - 12 EP - 22 PG - 11 SN - 0306-4522 DO - 10.1016/j.neuroscience.2017.09.032 UR - https://m2.mtmt.hu/api/publication/31223462 ID - 31223462 AB - Little is known about how the central nervous system prepares postural responses differently in anticipated compared to non-anticipated perturbations. To investigate this, participants were exposed to translational and rotational perturbations presented in a blocked (anticipated) and a random (non-anticipated) design. The preparatory setting ('central set') was measured by H-reflexes,motor-evoked potentials (MEPs), and short-interval intracortical inhibition (SICI) shortly before perturbation onset in the soleus of 15 healthy adults. Additionally, the behavioral consequences of differential preparatory settings were analyzed by comparing the short- (SLR), medium- (MLR), and long-latency response (LLR) of the soleus after anticipated and non-anticipated rotations and translations. H-reflexes elicited before perturbation were different between conditions (p = 0.023) with larger amplitudes in anticipated translations compared to anticipated rotations (37.0%; p = 0.048). Reduced SICI was found in the three conditions containing perturbations compared to static standing (p < 0.001). Muscular responses assessed after perturbations remained unchanged for the SLR and MLR, whereas the LLR was decreased in anticipated rotations (-36.2%; p = 0.002) and increased in anticipated translations (16.7%; p = 0.046) compared to the corresponding non-anticipated perturbation. As the SLR and MLR are organized at the spinal and the LLR at the cortical level, the preparatory setting seems to mainly influence cortically mediated postural responses. However, the modulation of the H-reflex before anticipated perturbations indicates that supraspinal centers adjusted la-afferent transmission for the soleus in a perturbation-specific manner. Intracortical inhibition was also modulated but differentiates to a lesser extent only between perturbation conditions and unperturbed stance. (C) 2017 The Authors. Published by Elsevier Ltd on behalf of IBRO. LA - English DB - MTMT ER - TY - JOUR AU - Mouthon, Audrey A. AU - Ruffieux, Jan AU - Keller, Martin AU - Taube, Wolfgang TI - Age-Related Differences in Corticospinal Excitability during Observation and Motor Imagery of Balance Tasks JF - FRONTIERS IN AGING NEUROSCIENCE J2 - FRONT AGING NEUROSCI VL - 8 PY - 2016 PG - 9 SN - 1663-4365 DO - 10.3389/Tnaci.2016.00317 UR - https://m2.mtmt.hu/api/publication/31223463 ID - 31223463 AB - Postural control declines across adult lifespan. Non-physical balance training has been suggested as an alternative to improve postural control in frail/immobilized elderly people. Previous studies showed that this kind of training can improve balance control in young and older adults. However, it is unclear whether the brain of young and older adults is activated differently during mental simulations of balance tasks. For this purpose, soleus (SOL) and tibialis motor evoked potentials (MEPs) and SOL H-reflexes were elicited while 15 elderly (mean +/- SD = 71 +/- 4.6 years) and 15 young participants (mean +/- SD = 27 +/- 4.6 years) mentally simulated static and dynamic balance tasks using motor imagery (MI), action observation (AO) or the combination of AO and MI (AO + MI). Young subjects displayed significant modulations of MEPs that depended on the kind of mental simulation and the postural task. Elderly adults also revealed differences between tasks, but not between mental simulation conditions. Furthermore, the elderly displayed larger MEP facilitation during mental simulation (AGE-GROUP; F-(1,F-28) 5.9; p = 0.02) in the SOL muscle compared to the young and a task-dependent modulation of the tibialis background electromyography (bEMG) activity. H-reflex amplitudes and bEMG in the SOL showed neither task - nor age-dependent modulation. As neither mental simulation nor balance tasks modulated H-reflexes and bEMG in the SOL muscle, despite large variations in the MEP-amplitudes, there seems to be an age-related change in the internal cortical representation of balance tasks. Moreover, the modulation of the tibialis bEMG in the elderly suggests that aging partially affects the ability to inhibit motor output. LA - English DB - MTMT ER - TY - JOUR AU - Papegaaij, Selma AU - Taube, Wolfgang AU - van Keeken, Helco G. AU - Otten, Egbert AU - Baudry, Stéphane AU - Hortobágyi, Tibor TI - Postural challenge affects motor cortical activity in young and old adults JF - EXPERIMENTAL GERONTOLOGY J2 - EXP GERONTOL VL - 73 PY - 2016 SP - 78 EP - 85 PG - 8 SN - 0531-5565 DO - 10.1016/j.exger.2015.11.015 UR - https://m2.mtmt.hu/api/publication/32008404 ID - 32008404 LA - English DB - MTMT ER -