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P1065: Induction of motor associative plasticity in the posterior parietal cortex–primary motor network
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Abstracts of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339
before and after the exercise on day 1 (T0, T1) and after the exercise on day 5 (T2). Basketball players attended only to T0 and T1. Results: In FCR of the sedentary group (Fig. 1, amplitude ratios, blue: T0, red: T1, green: T2, bars: standard deviations), there were less short latency afferent inhibition and higher facilitation at T1 (statistically significant at ISI 35 and 50 ms). This effect decreased at T2 despite the increased success rate. Basketball players did not show a facilitation as high as that found in the sedentary group. Conclusion: Short term exercises lead to SMI changes which may function in the early phase of gaining the ability. Continued training provided higher success while the electrophysiological changes was decreasing, possibly by the conversion of the learning process into different mechanisms. Exercising already gained abilities do not produce similar SMI changes.
P1064 Phasic muscle contraction influence upon the quadripulse stimulation (QPS) after effects S. Kadowaki 1 , H. Enomoto 1 , A. Moriya 1 , T. Murakami 1 , K. Nakamura 1 , S. Naktani-Enomoto 1 , H. Mochizuki 1,2 , S. Kobayashi 1 , Y. Ugawa 1 1 Fukushima Medical University, Neurology, Fukushima, Japan; 2 University of Miyazaki, Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Factory o Medicine, Miyazaki, Japan Question: The after effects elicited by repetitive transcranial magnetic stimulation (rTMS), such as theta burst stimulation (TBS), paired associative stimulation (PAS), are readily influenced by voluntary contraction of the target muscle. No investigations have suited the voluntary contraction effects on the after effects induced by quadripulse stimulation (QPS) (a novel rTMS technique). The aim of this study is to investigate whether or not QPS after effects are influenced by voluntary movements after the stimulation. Methods: Twelve healthy volunteers participated in this study. QPSs were applied upon the hot spot for the right first dorsal interossei (FDI) muscle (left M1). Inter stimulus intervals (ISIs) were set at 5 ms and 50 ms (QPS-5 and QPS-50) to induce strongest long term potentiation/depression (LTP/LTD) like effects, respectively. We compared three conditions; control without voluntary contraction and two contraction conditions, in which the subjects performed 60 cycles of opening-closing right hand movements (at the rate of 1 cycle per second) at immediately or 20 min after QPSs. MEPs were recorded from the right FDI 0 to 60 minutes after QPS. The time courses of MEP size were compared among the three conditions. Results: In the control condition, QPS-5 potentiated and QPS-50 depressed MEPs through 60 minutes thereafter. The voluntary movements just after QPSs abolished both LTP and LTD like after effects completely. On the other hand, the voluntary contraction 20 min after QPS transiently weakened both LTP and LTD like effects, and both effects finally caught up with the control levels. Conclusions: The after effects of QPS are influenced by voluntary contraction of the target muscle. The pattern of influence depends on the time when the voluntary contraction was performed.
P1065 Induction of motor associative plasticity in the posterior parietal cortex–primary motor network C.-C. Chao 1 , A.N. Karabanov 2 , R. Paine 3 , M. Hallett 3 , S.-T. Hsieh 1 National Taiwan University Hospital, Neurology, Taipei, Taiwan; 2 Copenhagen University, Department of Exercise and Sport Sciences, Copenhagen, Denmark; 3 National Institute of Neurological Disorder and Stroke, Human Motor Control Section, Bethesda, United States 1
There is anatomical and functional connectivity between the ipsilateral primary motor area (M1) and posterior parietal cortex (PPC), which plays a role in sensorimotor integration. In this study, we applied corticocortical paired associative stimuli to ipsilateral PPC and M1 (parietal ccPAS) in healthy right-handed subjects to test if this procedure could modulate M1 excitability and PPC-M1 connectivity. 180 paired transcranial magnetic stimuli to the PPC and M1 at an interstimulus interval (ISI) of 8 ms were delivered at 0.2 Hz. We found left parietal ccPAS increased excitability of conditioned left M1 assessed by motor evoked potentials (MEPs) and the input-output curve. Motor behavior as assessed by the Purdue Pegboard task was unchanged compared to controls. At baseline conditioning stimuli over left PPC potentiated MEPs from left M1 when ISI was 8 ms. This interaction significantly attenuated at 60 minutes after left parietal ccPAS.
Figure 1
Additional experiments showed that parietal ccPAS induced plasticity was timing-dependent and was absent if ISI was 100 ms, and could also be seen in the right hemisphere. Our results suggest that parietal ccPAS can both induce associative plasticity in M1 and modulate PPC-M1 connectivity. Parietal ccPAS is a new approach to modify motor excitability and sensorimotor interaction.
P1066 Movement preparation requires early activation of the dorsal premotor area R. Fleischmann, S. Schmidt, R. Bathe-Peters, M. Roennefarth, S.A. Brandt Charité - Universitaetsmedizin Berlin, Department of Neurology, Berlin, Germany Introduction: The human premotor cortex (PMC) is located in the center of a frontoparietal motor network. Its significance in a hierarchical motor network remains, however, elusive. The temporal pattern of local cortical activation during the performance of behavioral tasks can be studied by TMS induced virtual lesion models. Virtual lesions are understood to provide information about the functional role of cortical areas in a larger network. This study aims to identify the temporal activation pattern of the dorsal PMC during an established behavioral task demanding premotor activation. Methods: Nine healthy volunteers participated in the experiment. Navigated TMS was used to map Brodmann areae 4 and 6 for a primary motor (M1) and premotor stimulation hotspot. Then, subjects had to manually trace a figure while TMS was randomly applied over the PMC, M1 or the dorsolateral prefrontal cortex (DLPFC) as control condition at different time intervals before direction changes in the figure occurred. Results: NTMS over studied regions significantly affected task performance at discrete time intervals (F(10,80) =3.25, p=0.001). NTMS applied over PMC 120 and 140 ms before direction changes impaired task performance significantly more than when applied over M1 (p=0.021 and p=0.003) or DLPFC (p=0.017 and p<0.001). Discussion: We provide novel evidence that premotor activation is crucial for task performance early in the stage of motor preparation suggesting a significant role in shaping voluntary movement. This interpretation is supported by the observation of complex movements induced by direct cortical stimulation in the premotor area und higher-order motor deficits after premotor lesions.
P1067 Continuous theta burst stimulation with monophasic pulses: effect of current direction R. Hannah 1 , M. Ciocca 1,2 , M. Sommer 1,3 , P. Hammond 1 , J. Rothwell 1 1 University College London, Sobell Department of Motor Neuroscience and Movement Disorders, London, United Kingdom; 2 Fondazione IRCCS Ca’Granda Ospedale Maggiore Policlinico, Centro Clinico per la Neurostimolazione, Milan, Italy; 3 University of Goettingen, Department of Clinical Neurophysiology, Goettingen, Germany Question: In a companion poster (Sommer et al.) we show that iTBS with a
Abstracts of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339
before and after the exercise on day 1 (T0, T1) and after the exercise on day 5 (T2). Basketball players attended only to T0 and T1. Results: In FCR of the sedentary group (Fig. 1, amplitude ratios, blue: T0, red: T1, green: T2, bars: standard deviations), there were less short latency afferent inhibition and higher facilitation at T1 (statistically significant at ISI 35 and 50 ms). This effect decreased at T2 despite the increased success rate. Basketball players did not show a facilitation as high as that found in the sedentary group. Conclusion: Short term exercises lead to SMI changes which may function in the early phase of gaining the ability. Continued training provided higher success while the electrophysiological changes was decreasing, possibly by the conversion of the learning process into different mechanisms. Exercising already gained abilities do not produce similar SMI changes.
P1064 Phasic muscle contraction influence upon the quadripulse stimulation (QPS) after effects S. Kadowaki 1 , H. Enomoto 1 , A. Moriya 1 , T. Murakami 1 , K. Nakamura 1 , S. Naktani-Enomoto 1 , H. Mochizuki 1,2 , S. Kobayashi 1 , Y. Ugawa 1 1 Fukushima Medical University, Neurology, Fukushima, Japan; 2 University of Miyazaki, Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Factory o Medicine, Miyazaki, Japan Question: The after effects elicited by repetitive transcranial magnetic stimulation (rTMS), such as theta burst stimulation (TBS), paired associative stimulation (PAS), are readily influenced by voluntary contraction of the target muscle. No investigations have suited the voluntary contraction effects on the after effects induced by quadripulse stimulation (QPS) (a novel rTMS technique). The aim of this study is to investigate whether or not QPS after effects are influenced by voluntary movements after the stimulation. Methods: Twelve healthy volunteers participated in this study. QPSs were applied upon the hot spot for the right first dorsal interossei (FDI) muscle (left M1). Inter stimulus intervals (ISIs) were set at 5 ms and 50 ms (QPS-5 and QPS-50) to induce strongest long term potentiation/depression (LTP/LTD) like effects, respectively. We compared three conditions; control without voluntary contraction and two contraction conditions, in which the subjects performed 60 cycles of opening-closing right hand movements (at the rate of 1 cycle per second) at immediately or 20 min after QPSs. MEPs were recorded from the right FDI 0 to 60 minutes after QPS. The time courses of MEP size were compared among the three conditions. Results: In the control condition, QPS-5 potentiated and QPS-50 depressed MEPs through 60 minutes thereafter. The voluntary movements just after QPSs abolished both LTP and LTD like after effects completely. On the other hand, the voluntary contraction 20 min after QPS transiently weakened both LTP and LTD like effects, and both effects finally caught up with the control levels. Conclusions: The after effects of QPS are influenced by voluntary contraction of the target muscle. The pattern of influence depends on the time when the voluntary contraction was performed.
P1065 Induction of motor associative plasticity in the posterior parietal cortex–primary motor network C.-C. Chao 1 , A.N. Karabanov 2 , R. Paine 3 , M. Hallett 3 , S.-T. Hsieh 1 National Taiwan University Hospital, Neurology, Taipei, Taiwan; 2 Copenhagen University, Department of Exercise and Sport Sciences, Copenhagen, Denmark; 3 National Institute of Neurological Disorder and Stroke, Human Motor Control Section, Bethesda, United States 1
There is anatomical and functional connectivity between the ipsilateral primary motor area (M1) and posterior parietal cortex (PPC), which plays a role in sensorimotor integration. In this study, we applied corticocortical paired associative stimuli to ipsilateral PPC and M1 (parietal ccPAS) in healthy right-handed subjects to test if this procedure could modulate M1 excitability and PPC-M1 connectivity. 180 paired transcranial magnetic stimuli to the PPC and M1 at an interstimulus interval (ISI) of 8 ms were delivered at 0.2 Hz. We found left parietal ccPAS increased excitability of conditioned left M1 assessed by motor evoked potentials (MEPs) and the input-output curve. Motor behavior as assessed by the Purdue Pegboard task was unchanged compared to controls. At baseline conditioning stimuli over left PPC potentiated MEPs from left M1 when ISI was 8 ms. This interaction significantly attenuated at 60 minutes after left parietal ccPAS.
Figure 1
Additional experiments showed that parietal ccPAS induced plasticity was timing-dependent and was absent if ISI was 100 ms, and could also be seen in the right hemisphere. Our results suggest that parietal ccPAS can both induce associative plasticity in M1 and modulate PPC-M1 connectivity. Parietal ccPAS is a new approach to modify motor excitability and sensorimotor interaction.
P1066 Movement preparation requires early activation of the dorsal premotor area R. Fleischmann, S. Schmidt, R. Bathe-Peters, M. Roennefarth, S.A. Brandt Charité - Universitaetsmedizin Berlin, Department of Neurology, Berlin, Germany Introduction: The human premotor cortex (PMC) is located in the center of a frontoparietal motor network. Its significance in a hierarchical motor network remains, however, elusive. The temporal pattern of local cortical activation during the performance of behavioral tasks can be studied by TMS induced virtual lesion models. Virtual lesions are understood to provide information about the functional role of cortical areas in a larger network. This study aims to identify the temporal activation pattern of the dorsal PMC during an established behavioral task demanding premotor activation. Methods: Nine healthy volunteers participated in the experiment. Navigated TMS was used to map Brodmann areae 4 and 6 for a primary motor (M1) and premotor stimulation hotspot. Then, subjects had to manually trace a figure while TMS was randomly applied over the PMC, M1 or the dorsolateral prefrontal cortex (DLPFC) as control condition at different time intervals before direction changes in the figure occurred. Results: NTMS over studied regions significantly affected task performance at discrete time intervals (F(10,80) =3.25, p=0.001). NTMS applied over PMC 120 and 140 ms before direction changes impaired task performance significantly more than when applied over M1 (p=0.021 and p=0.003) or DLPFC (p=0.017 and p<0.001). Discussion: We provide novel evidence that premotor activation is crucial for task performance early in the stage of motor preparation suggesting a significant role in shaping voluntary movement. This interpretation is supported by the observation of complex movements induced by direct cortical stimulation in the premotor area und higher-order motor deficits after premotor lesions.
P1067 Continuous theta burst stimulation with monophasic pulses: effect of current direction R. Hannah 1 , M. Ciocca 1,2 , M. Sommer 1,3 , P. Hammond 1 , J. Rothwell 1 1 University College London, Sobell Department of Motor Neuroscience and Movement Disorders, London, United Kingdom; 2 Fondazione IRCCS Ca’Granda Ospedale Maggiore Policlinico, Centro Clinico per la Neurostimolazione, Milan, Italy; 3 University of Goettingen, Department of Clinical Neurophysiology, Goettingen, Germany Question: In a companion poster (Sommer et al.) we show that iTBS with a