Multi-muscle TMS mapping for motor cortex reorganization during finger independence training
Poster No:
119
Submission Type:
Abstract Submission
Authors:
Anastasiia Asmolova1, Anastasiia Sukmanova2, Milana Makarova2, Pavel Novikov2, Vadim Nikulin3, Arno Villringer3,4, Maria Nazarova5,6
Institutions:
1Max Planck School of Cognition, Leipzig, Germany, 2National Research University Higher School of Economics, Moscow, Russian Federation, 3Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 4Leipzig University, Leipzig, Germany, 5Aalto University, Helsinki, Finland, 6Harvard Medical School, Boston, MA
First Author:
Co-Author(s):
Anastasiia Sukmanova
National Research University Higher School of Economics
Moscow, Russian Federation
National Research University Higher School of Economics
Moscow, Russian Federation
Arno Villringer
Max Planck Institute for Human Cognitive and Brain Sciences|Leipzig University
Leipzig, Germany|Leipzig, Germany
Max Planck Institute for Human Cognitive and Brain Sciences|Leipzig University
Leipzig, Germany|Leipzig, Germany
Introduction:
MRI-navigated transcranial magnetic stimulation (nTMS) is an approach widely used for non-invasively mapping of the motor cortex. In our recent test-retest study we established the absolute and relative reliability of multi-muscle nTMS motor mapping (Nazarova et al., 2021). Given that motor learning is known to alter plasticity in the motor cortex (Raffin & Siebner, 2019), our current objective was to explore the reorganization of the muscle cortical representations (MCRs) following finger-independence training.
Methods:
26 healthy young right-handed male volunteers (18-35 y.o.) underwent two nTMS mapping sessions separated by ten sessions of the finger-independence training using EMG-based biofeedback (TMSphi, Novikov et al., 2020). During nTMS motor mapping MRI surface EMG was recorded from abductor pollicis brevis (APB), abductor digiti minimi (ADM), first dorsal interosseous (FDI), extensor digitorum communis (EDC) and biceps brachii. Within the 10 motor training sessions participants were mastering their motor task consisting of abducting their thumb while keeping their little finger still. As behavioral outcomes we measured: the success of the independent muscle contraction (in % from the maximum muscle contraction), amplitudes of the maximum voluntary contraction (MVC) of the trained muscles (APB, ADM) and general hand dexterity using 9-hole peg test (9HPT). For nTMS motor mapping, MCRs and their parameters (Figure 1) were evaluated using TMSmap software (Novikov et al., 2018).
Results:
The success of independent contraction increased: for APB from 16% to 29% (p = 0.003, all p-values are FDR-corrected), for ADM – from 16% to 30% (p = 0.004). Time of the 9HPT performance significantly decreased from 19.96 s to 18.42 s (p = 0.005). The amplitudes of APB and ADM MVC did not change significantly. At the group level changes in the MCR parameters were not significant, showing only a trend for increase (APB MCR area increased from 6.17 to 6.81 cm2, ADM MCR - from 5.22 to 5.92 cm2). Comparing to the smallest detectable changes (SDC) from our previous test-retest reliability study (Nazarova et al., 2021) APB MCR area significantly increased in 7 participants and decreased in 4 ( >2.01 cm2, CI – 95%); while ADM MCR area increased in 5 and decreased in 4 participants ( >2.11 cm2, CI – 95%); the normalized overlap between APB and ADM MCRs increased in 1 - decreased in 2 ( >0.34%, CI – 95%).
Conclusions:
We showed that the finger-independence training significantly increased hand dexterity, but not hand strength – the finding which is in line with the previous studies showing that hand strength and dexterity are not associated directly (Jing Xu et al., 2017). Our TMS findings do not support the hypothesis that the overlaps between muscles trained to be independent may decrease as it was shown in case of finger immobilization (Raffin & Siebner, 2019). We suppose that it may be explained by the fact that both voluntarily contraction and relaxation of both muscles (APB, ADM) were needed for the motor task performance. TMS maps changes reflecting voluntary muscle relaxation training should be investigated in further studies.
Brain Stimulation:
Non-invasive Magnetic/TMS
TMS 1
Motor Behavior:
Motor Behavior Other 2
Keywords:
Motor
Plasticity
Transcranial Magnetic Stimulation (TMS)
Other - Motor mapping, motor training
1|2Indicates the priority used for review
Provide references using author date format
Novikov, P. A., Nazarova, M. A., & Nikulin, V. V. (2018). TMSmap – Software for Quantitative Analysis of TMS Mapping Results. Frontiers in Human Neuroscience, 12, 239.
Novikov P.A., Reshetnikov M.L., Nazarova M.A., Gribov D.A., Nikulin. V. V. (2020). Nejronavigaciya TMSphi. Byul. №2, Reestr programm dlya EVM.
Raffin, E., & Siebner, H. R. (2019). Use-Dependent Plasticity in Human Primary Motor Hand Area: Synergistic Interplay Between Training and Immobilization. Cerebral Cortex (New York, N.Y. : 1991), 29(1), 356–371.
Jing Xu, X., Naveed Ejaz, X., Hertler, B., Branscheidt, M., Widmer, M., Faria, A. V, Harran, M. D., Cortes, J. C., Kim, N., Celnik, P. A., Kitago, T., Andreas Luft, X. R., Krakauer, J. W., Diedrichsen, J., Xu, J., & Ejaz, N. (2017). Separable systems for recovery of finger strength and control after stroke Even healthy people show in-voluntary force production (enslaving) on the uninstructed. J Neurophysiol, 118, 1151–1163.