- Email: [email protected]
P1067: Continuous theta burst stimulation with monophasic pulses: effect of current direction
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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
monophasic anterior-posterior (AP) current pulse, which differs from conventional TBS applied with biphasic pulses (Huang et al. 2005), produces reliable suppression of corticospinal excitability. Here we test the effect of applying cTBS with the same monophasic pulses. Methods: We stimulated the dominant hand representation of the motor cortex in 15 healthy subjects, using approximately square wave pulses (see Fig 1 Peterchev et al. 2013), generated by a prototype controllable TMS machine (cTMS-3, Rogue Resolutions Ltd., Cardiff, UK), connected to a standard figure-of-eight coil with an outer diameter of each wing of 70 mm (The Magstim Co. Ltd., Dyfed, United Kingdom). cTBS was applied conventionally (200 bursts at 5 Hz burst repetition frequency, each burst consisting of 3 pulses of 80% AMT intensity repeated at 50 Hz frequency). In two separate sessions, we applied a pulse width of 75 microseconds in the posterio-anterior (PA) current direction in the brain, and of 45 microseconds in the AP direction. Before and every 5 minutes up to 30 minutes after cTBS, we monitored the modulation of motor evoked potential (MEP) amplitude from the dominant first dorsal interosseous using blocks of conventional, monophasic, suprathreshold pulses generated by a Magstim 2002 stimulator, inducing PA currents in the brain, at 0.2 Hz frequency. Results: There was a large variation in response between individuals such that a rmANOVA using data from all points failed to show any effect of AP or PA stimulation and no difference between them. However, averaging all post-cTBS time points for comparison with baseline showed a significant MEP suppression after AP (mean suppression to 80% control, paired t-test p=0.044) but not PA stimulation.
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muscle was significantly shorter when stimulating left hemisphere (1.4 ms) compared to right hemisphere stimulation (2.3 ms) in AS group (p<0.005, pairwise comparison and hand × group interaction), whereas no interhemispheric differences were seen in controls (3.1 ms vs. 2.8. ms). Furthermore, the AS children had significantly larger cortical representation area of right abductor digiti minimi muscle compared to their left ADM as well as compared to control children (p<0.05, pairwise comparison and hand × group interaction). Conclusions: Children with AS possess alterations in motor cortex function and extent of representation area on the left hemisphere. These results may underlie some of the known motor abnormalities and impairment in manual dexterity in AS.
P1069 The size of motor representation areas of distal hand muscles enlarge with age L. Saeisaenen 1 , M. Koenoenen 1,2 , E. Mervaala 1,3 , N. Lintu 4 , T. Lakka 4 , M. Anttonen 3 , P. Julkunen 3 , S. Maeaettae 1,3 1 University of Eastern Finland, Clinical Neurophysiology, Kuopio, Finland; 2 Kuopio University Hospital, Clinical Radiology, Kuopio, Finland; 3 Kuopio University Hospital, Clinical Neurophysiology, Kuopio, Finland; 4 University of Eastern Finland, Clinical Biomedicine, Clinical Physiology, Kuopio, Finland
Conclusions: Monophasic AP cTBS (like iTBS) tends to suppress corticospinal excitability but individual variability is high. PA cTBS has no reliable effect. References: Peterchev et al. (2013) Pulse width dependence of motor threshold and input-output curve characterized with controllable pulse parameter transcranial magnetic stimulation, Clin Neurophysiol Huang et al. (2005) Theta burst stimulation of the human motor cortex, Neuron
Question: We wanted to characterize the motor representation areas of distal hand muscle in developing brain by studying healthy children, adolescents and young adults with MRI-navigated transcranial magnetic stimulation (nTMS) on both hemispheres. Method: 45 healthy right-handed subjects were divided into four age groups: young children (6-8 yrs, n=7), children, (9-12 yrs, n=14), adolescence (14-17 yrs, n=12) and adults (22-33 yrs, n=12). Optimal representation site for abductor pollicis brevis (APB) was located and resting motor threshold (rMT) determined using nTMS. Functional motor areas were mapped at 110% of rMT. Results: MT decreased with age (main effect of group, p<0.000). Optimal site for APB was located in the anatomical hand knob in all age groups on and both hemispheres. However, the size of representation area of APB differed between the groups (p<0.05, linear mixed model, main effect of group). Young children had significantly smaller cortical representation area of APB compared to older children, adolescents and adults (pairwise comparison; p<0.05 in all comparisons). Furthermore, older children had smaller representation area than adolescents, whereas in adolescents, the representation areas of APB had reached maturity. Inter-hemispheric differences were not found in any age groups (p<0.05). Conclusions: Cortical representation areas of distal hand muscles enlarge with age. The results demonstrate the development of the cerebral cortex, specifically the motor cortex.
P1068 Motor cortical representations differ between Asperger and typical children – navigated TMS study
P1070 Motor evoked potentials studied by navigated TMS during normal development – from six years to adulthood
L. Saeisaenen 1 , S. Maeaettae 1,2,3 , P. Julkunen 3 , T. Hukkanen 3 , N. Lintu 4 , V. Lindi 4 , T. Lakka 4 , R. Vanninen 5 , I. Makkonen 6 1 University of Eastern Finland, Clinical Medicine, Clinical Neurophysiology, Kuopio, Finland; 2 University of Eastern Finland, Clinical Neurophysiology, Kuopio, Finland; 3 Kuopio University Hospital, Clinical Neurophysiology, Kuopio, Finland; 4 University of Eastern Finland, Clinical Biomedicine, Clinical Physiology, Kuopio, Finland; 5 Kuopio University Hospital, Clinical Radiology, Kuopio, Finland; 6 Kuopio University Hospital, Child Neurophysiology, Kuopio, Finland
L. Saeisaenen 1,2 , S. Maeaettae 1,2 , P. Julkunen 3 , A.-M. Eloranta 4 , T. Lakka 4 , S. Heikkinen-Knuuttila 2 , E. Mervaala 1,2 , M. Koenoenen 3,2 1 University of Eastern Finland, Clinical Neurophysiology, Kuopio, Finland; 2 Kuopio University Hospital, Clinical Neurophysiology, Kuopio, Finland; 3 Kuopio University Hospital, Clinical Radiology, Kuopio, Finland; 4 University of Eastern Finland, Biomedicine/Clinical physiology, Kuopio, Finland
Figure 1
Question: Motor functions are impaired in autism spectrum disorders. Our aim was to characterize Asperger’s syndrome (AS) using transcranial magnetic stimulation (TMS). Specifically, we studied cortical functions and representations of distal hand muscles using MRI-navigated TMS (nTMS). Method: Eight boys with AS (age 8-11 years) and age-matched neurotypical controls were studied. The resting motor threshold (MT), motor evoked potentials (MEP), latency jump and motor cortex mapping on both hemispheres were measured. Fine motor function was assessed by Box and Block Test (BBT). Results: The controls demonstrated better fine motor skills (BBT; main effect of group, p=0.005). There were no significant differences in MT, MEP latency or MEP amplitude. Latency jump in abductor pollicis brevis
Question: We examined navigated transcranial magnetic stimulation (nTMS) measures (resting motor threshold (MT), motor evoked potential (MEP) latency and amplitude, active MEP latency) as possible markers of cortical maturation and correlated them with a simple fine motor skill task. Method: NTMS was performed on both hemispheres on 46 right-handed subjects (young children: n=10, mean 7.6 yrs; children, n=12, mean 10.8 yrs; adolescents, n=12, mean 15.8 yrs and adults, n=12, 28 yrs). nTMS was targeted to the optimal representation site of abductor pollicis brevis muscle (APB). Fine motor skills were assessed by box and block test (BBT). Results: The examination was well tolerated with no side-effects. Fine motor skills improved with age (main effect of group, p=0.000; BBT means 52, 66, 75 and 84). MT decreased with age (main effect of group, p<0.000, means: 71%, 51%, 40% and 40%). In one child from the youngest age group the MT was above the maximal stimulator output. Both resting MEP latency
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
monophasic anterior-posterior (AP) current pulse, which differs from conventional TBS applied with biphasic pulses (Huang et al. 2005), produces reliable suppression of corticospinal excitability. Here we test the effect of applying cTBS with the same monophasic pulses. Methods: We stimulated the dominant hand representation of the motor cortex in 15 healthy subjects, using approximately square wave pulses (see Fig 1 Peterchev et al. 2013), generated by a prototype controllable TMS machine (cTMS-3, Rogue Resolutions Ltd., Cardiff, UK), connected to a standard figure-of-eight coil with an outer diameter of each wing of 70 mm (The Magstim Co. Ltd., Dyfed, United Kingdom). cTBS was applied conventionally (200 bursts at 5 Hz burst repetition frequency, each burst consisting of 3 pulses of 80% AMT intensity repeated at 50 Hz frequency). In two separate sessions, we applied a pulse width of 75 microseconds in the posterio-anterior (PA) current direction in the brain, and of 45 microseconds in the AP direction. Before and every 5 minutes up to 30 minutes after cTBS, we monitored the modulation of motor evoked potential (MEP) amplitude from the dominant first dorsal interosseous using blocks of conventional, monophasic, suprathreshold pulses generated by a Magstim 2002 stimulator, inducing PA currents in the brain, at 0.2 Hz frequency. Results: There was a large variation in response between individuals such that a rmANOVA using data from all points failed to show any effect of AP or PA stimulation and no difference between them. However, averaging all post-cTBS time points for comparison with baseline showed a significant MEP suppression after AP (mean suppression to 80% control, paired t-test p=0.044) but not PA stimulation.
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muscle was significantly shorter when stimulating left hemisphere (1.4 ms) compared to right hemisphere stimulation (2.3 ms) in AS group (p<0.005, pairwise comparison and hand × group interaction), whereas no interhemispheric differences were seen in controls (3.1 ms vs. 2.8. ms). Furthermore, the AS children had significantly larger cortical representation area of right abductor digiti minimi muscle compared to their left ADM as well as compared to control children (p<0.05, pairwise comparison and hand × group interaction). Conclusions: Children with AS possess alterations in motor cortex function and extent of representation area on the left hemisphere. These results may underlie some of the known motor abnormalities and impairment in manual dexterity in AS.
P1069 The size of motor representation areas of distal hand muscles enlarge with age L. Saeisaenen 1 , M. Koenoenen 1,2 , E. Mervaala 1,3 , N. Lintu 4 , T. Lakka 4 , M. Anttonen 3 , P. Julkunen 3 , S. Maeaettae 1,3 1 University of Eastern Finland, Clinical Neurophysiology, Kuopio, Finland; 2 Kuopio University Hospital, Clinical Radiology, Kuopio, Finland; 3 Kuopio University Hospital, Clinical Neurophysiology, Kuopio, Finland; 4 University of Eastern Finland, Clinical Biomedicine, Clinical Physiology, Kuopio, Finland
Conclusions: Monophasic AP cTBS (like iTBS) tends to suppress corticospinal excitability but individual variability is high. PA cTBS has no reliable effect. References: Peterchev et al. (2013) Pulse width dependence of motor threshold and input-output curve characterized with controllable pulse parameter transcranial magnetic stimulation, Clin Neurophysiol Huang et al. (2005) Theta burst stimulation of the human motor cortex, Neuron
Question: We wanted to characterize the motor representation areas of distal hand muscle in developing brain by studying healthy children, adolescents and young adults with MRI-navigated transcranial magnetic stimulation (nTMS) on both hemispheres. Method: 45 healthy right-handed subjects were divided into four age groups: young children (6-8 yrs, n=7), children, (9-12 yrs, n=14), adolescence (14-17 yrs, n=12) and adults (22-33 yrs, n=12). Optimal representation site for abductor pollicis brevis (APB) was located and resting motor threshold (rMT) determined using nTMS. Functional motor areas were mapped at 110% of rMT. Results: MT decreased with age (main effect of group, p<0.000). Optimal site for APB was located in the anatomical hand knob in all age groups on and both hemispheres. However, the size of representation area of APB differed between the groups (p<0.05, linear mixed model, main effect of group). Young children had significantly smaller cortical representation area of APB compared to older children, adolescents and adults (pairwise comparison; p<0.05 in all comparisons). Furthermore, older children had smaller representation area than adolescents, whereas in adolescents, the representation areas of APB had reached maturity. Inter-hemispheric differences were not found in any age groups (p<0.05). Conclusions: Cortical representation areas of distal hand muscles enlarge with age. The results demonstrate the development of the cerebral cortex, specifically the motor cortex.
P1068 Motor cortical representations differ between Asperger and typical children – navigated TMS study
P1070 Motor evoked potentials studied by navigated TMS during normal development – from six years to adulthood
L. Saeisaenen 1 , S. Maeaettae 1,2,3 , P. Julkunen 3 , T. Hukkanen 3 , N. Lintu 4 , V. Lindi 4 , T. Lakka 4 , R. Vanninen 5 , I. Makkonen 6 1 University of Eastern Finland, Clinical Medicine, Clinical Neurophysiology, Kuopio, Finland; 2 University of Eastern Finland, Clinical Neurophysiology, Kuopio, Finland; 3 Kuopio University Hospital, Clinical Neurophysiology, Kuopio, Finland; 4 University of Eastern Finland, Clinical Biomedicine, Clinical Physiology, Kuopio, Finland; 5 Kuopio University Hospital, Clinical Radiology, Kuopio, Finland; 6 Kuopio University Hospital, Child Neurophysiology, Kuopio, Finland
L. Saeisaenen 1,2 , S. Maeaettae 1,2 , P. Julkunen 3 , A.-M. Eloranta 4 , T. Lakka 4 , S. Heikkinen-Knuuttila 2 , E. Mervaala 1,2 , M. Koenoenen 3,2 1 University of Eastern Finland, Clinical Neurophysiology, Kuopio, Finland; 2 Kuopio University Hospital, Clinical Neurophysiology, Kuopio, Finland; 3 Kuopio University Hospital, Clinical Radiology, Kuopio, Finland; 4 University of Eastern Finland, Biomedicine/Clinical physiology, Kuopio, Finland
Figure 1
Question: Motor functions are impaired in autism spectrum disorders. Our aim was to characterize Asperger’s syndrome (AS) using transcranial magnetic stimulation (TMS). Specifically, we studied cortical functions and representations of distal hand muscles using MRI-navigated TMS (nTMS). Method: Eight boys with AS (age 8-11 years) and age-matched neurotypical controls were studied. The resting motor threshold (MT), motor evoked potentials (MEP), latency jump and motor cortex mapping on both hemispheres were measured. Fine motor function was assessed by Box and Block Test (BBT). Results: The controls demonstrated better fine motor skills (BBT; main effect of group, p=0.005). There were no significant differences in MT, MEP latency or MEP amplitude. Latency jump in abductor pollicis brevis
Question: We examined navigated transcranial magnetic stimulation (nTMS) measures (resting motor threshold (MT), motor evoked potential (MEP) latency and amplitude, active MEP latency) as possible markers of cortical maturation and correlated them with a simple fine motor skill task. Method: NTMS was performed on both hemispheres on 46 right-handed subjects (young children: n=10, mean 7.6 yrs; children, n=12, mean 10.8 yrs; adolescents, n=12, mean 15.8 yrs and adults, n=12, 28 yrs). nTMS was targeted to the optimal representation site of abductor pollicis brevis muscle (APB). Fine motor skills were assessed by box and block test (BBT). Results: The examination was well tolerated with no side-effects. Fine motor skills improved with age (main effect of group, p=0.000; BBT means 52, 66, 75 and 84). MT decreased with age (main effect of group, p<0.000, means: 71%, 51%, 40% and 40%). In one child from the youngest age group the MT was above the maximal stimulator output. Both resting MEP latency