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153. Modulation of corticomuscular coherences by proprioceptive somatomotor leg training
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Society Proceedings / Clinical Neurophysiology 120 (2009) e9–e88
Table 1 MEP contralateral AIS APB NP APB AIS ES3 NP ES3 AIS ES9 NP ES9
Left hemisphere x (cm) 2.7 ± 1.0 3.1 ± 1.0 1.1 ± 0.9 0.6 ± 0.6 0.9 ± 0.9 0.5 ± 0.9
Left hemisphere y (cm)
Right hemisphere x (cm)
Right hemisphere y (cm)
3.0 ± 0.9 2.7 ± 0.6 2.4 ± 0.9 1.8 ± 1.3 2.0 ± 0.7 2.2 ± 1.1
3.9 ± 1.0 3.5 ± 0.4 1.0 ± 0.8 0.9 ± 0.5 1.2 ± 1.0 0.8 ± 0.5
2,9 ± 0.5 2,7 ± 1.2 2.7 ± 0.6 1.9 ± 1.6 2.7 ± 0.9 2.2 ± 0.8
3) ES maps were larger in the RH than the LH in both AIS and NP: ES3 (AIS: RH 12 cm2/LH 8 cm2) vs (NP:RH 16 cm2/LH 11 cm2); ES9 (AIS:RH 14 cm2/LH 8 cm2) vs (NP:RH 16 cm2/LH 11 cm2). Conclusion: We confirm right hemispheric pathology in motor cortex of right convex AIS with a lateral shift of the hand representation and abnormal variability of erector spinae motor map location. This suggests that the motor cortex ipsilateral to the scoliosis convexity is involved in this disorder. doi:10.1016/j.clinph.2008.07.150
153. Modulation of corticomuscular coherences by proprioceptive somatomotor leg training—C. Reinsberger 1, J. Baumeister 2, M. Weiß 2, J. Claßen 1 (1 Bayerische Julius-Maximilians Universität, Neurologische Klinik, Würzburg, Germany, 2 Universität Paderborn, Department Sport & Gesundheit, Paderborn, Germany) Background: Corticomuscular coherence (CMC) is a measure of the degree of coupling of electrical oscillations arising in the cerebral cortex and muscles, but its functional significance is poorly understood. Little is known about the modulation of CMC by practice. As leg training has been shown to induce cortical plasticity, it might influence functional changes mediated by CMC. It remains unknown whether alterations of functional connectivity to the lower limb display regional specificity or rather affect the wider network of muscle control. Objective: To assess the effects of a somatomotor proprioceptive training of the lower limbs, on CMC to muscles of upper and lower limbs and to elucidate the role of CMC as an indicator of training-induced functional changes. Methods: We examined CMC at frequencies between 10 and 35 Hz in 10 healthy male volunteers before and after a somatomotor leg training with emphasis on proprioception on a training platform on oscillating bearings with aperiodically damped elements. This training involved (1) standing with both feet on the resting platform, (2) stepping on the platform with one leg with subsequent stabilization and (3) standing on the resting platform with one leg and stabilization after dismantling the brakes of the platform due to a standardized protocol. Multichannel (60 channels) EEG recordings were obtained, while surface EMG was recorded from the following muscles of the dominant leg at a slight isometric contraction before and after the leg training: abductor pollicis brevis (APB), vastus lateral (VL) and vastus medial (VM) muscle. CMC pre- and post-intervention was computed at different frequency bands between 10– 12 Hz, 13–21 Hz, 22–30 Hz and 31–35 Hz, and was compared by using a General Linear Model. Results: CMC could be obtained in all subjects. The magnitude of CMC depended on the target muscle and on the frequency band. CMC magnitude involving recordings from leg muscles (CMC-VL and CMC-VM) was maximal at 31-35 Hz (similar between VL and
VM), whereas CMC involving recordings from APB (CMC-APB) was maximal at a frequency around 22–30 Hz. After intervention, CMCVL increased highly significantly between 31 and 35 Hz (GLM: F = 12.323, p = 0.001). CMC-APB also increased at 31–35 Hz (GLM: F = 6.929, p = 0.009), but significantly decreased at frequencies between 22 and 30 Hz (GLM: F = 4.882, p = 0.028). Conclusions: As changes of CMC are not limited to the training muscle alone, it appears unlikely that CMC is a physiological substrate of training-induced functional changes. Alternatively, changes of functional connectivity induced by leg training may be more widespread to include cortical control of upper limb muscles. doi:10.1016/j.clinph.2008.07.151
154. Matching midbrain-sonography to its macroanatomic correlate—D. Weise, R. Gentner, J. Claßen (Universität Würzburg, Neurologie, Würzburg, Germany) Introduction: Transcranial sonography (TCS) is a recently established neuroimaging technique that allows visualizing several brainstem structures including the substantia nigra (SN). Using TCS, an echogenic region can be detected at the suspected anatomical location of the SN, and this echogenic area amounts to around 0.12 cm2 in healthy controls. Although the location of SN-echogenicity is consistent with the location of the anatomical location, it remains unknown which part of SN is displayed because the rostro-caudal level of the 2-dimensional ultrasound plane in relation to the longitudinal axis of the SN has never been formally established.The relationship between the normal macroscopic anatomic extension of the SN and the extension of the echogenic SN-area is also not known. Methods: The anatomical extension of the SN was measured in the probabilistic atlas of the human brainstem published by Afshar and colleagues (Afshar F et al., New York: Raven Press; 1978). In all SN-containing sectional planes the SN was encircled manually and its spatial extension was quantified with The GIMP, a freely distributed computer program. TCS was performed with Sonoline Elegra (Siemens; Erlangen, Germany) in conjunction with a neuronavigation system (Brainsight, Rogue Research, Canada). Subjects were registered to template (or individual) MRI scans in order to monitor the corresponding anatomical section plane currently visualized with TCS. With the TCS-probe connected to the Brainsight system we used MR images of the subject as a real time guide of the position of the probe and illustration of the insonated plane. Results: The anatomical extension of the normal SN as assessed planimetrically varied substantially along its caudo-rostral axis, and it ranged from 0.27 to 0.46 cm2. The sonographic appearance of the brainstem best matched one of the three rostral-most sections of the atlas, located 8-10 mm rostrally from the caudal end of the SN. At these levels the anatomical area of the SN amounted to 0.44– 0.46 cm2. With this neuronavigated TCS the region of the SN was identified and the corresponding ultrasound image freezed for quantitative measurements. Very small changes of the angulation of the probe led to significant changes of the insonated plane and the illustrated structures. Discussion: Greater anatomic extension of the SN than echogenic SN-area suggests that only part of SN can be visualized. This provides a basis for detecting extensions of SN-echogenicity in Parkinson’s disease. SN is usually evaluated in the most rostral sections, where pathological changes are known to be relatively mild. Neuronavigated TCS may enhance the diagnostic yield of midbrain sonography. doi:10.1016/j.clinph.2008.07.152
Society Proceedings / Clinical Neurophysiology 120 (2009) e9–e88
Table 1 MEP contralateral AIS APB NP APB AIS ES3 NP ES3 AIS ES9 NP ES9
Left hemisphere x (cm) 2.7 ± 1.0 3.1 ± 1.0 1.1 ± 0.9 0.6 ± 0.6 0.9 ± 0.9 0.5 ± 0.9
Left hemisphere y (cm)
Right hemisphere x (cm)
Right hemisphere y (cm)
3.0 ± 0.9 2.7 ± 0.6 2.4 ± 0.9 1.8 ± 1.3 2.0 ± 0.7 2.2 ± 1.1
3.9 ± 1.0 3.5 ± 0.4 1.0 ± 0.8 0.9 ± 0.5 1.2 ± 1.0 0.8 ± 0.5
2,9 ± 0.5 2,7 ± 1.2 2.7 ± 0.6 1.9 ± 1.6 2.7 ± 0.9 2.2 ± 0.8
3) ES maps were larger in the RH than the LH in both AIS and NP: ES3 (AIS: RH 12 cm2/LH 8 cm2) vs (NP:RH 16 cm2/LH 11 cm2); ES9 (AIS:RH 14 cm2/LH 8 cm2) vs (NP:RH 16 cm2/LH 11 cm2). Conclusion: We confirm right hemispheric pathology in motor cortex of right convex AIS with a lateral shift of the hand representation and abnormal variability of erector spinae motor map location. This suggests that the motor cortex ipsilateral to the scoliosis convexity is involved in this disorder. doi:10.1016/j.clinph.2008.07.150
153. Modulation of corticomuscular coherences by proprioceptive somatomotor leg training—C. Reinsberger 1, J. Baumeister 2, M. Weiß 2, J. Claßen 1 (1 Bayerische Julius-Maximilians Universität, Neurologische Klinik, Würzburg, Germany, 2 Universität Paderborn, Department Sport & Gesundheit, Paderborn, Germany) Background: Corticomuscular coherence (CMC) is a measure of the degree of coupling of electrical oscillations arising in the cerebral cortex and muscles, but its functional significance is poorly understood. Little is known about the modulation of CMC by practice. As leg training has been shown to induce cortical plasticity, it might influence functional changes mediated by CMC. It remains unknown whether alterations of functional connectivity to the lower limb display regional specificity or rather affect the wider network of muscle control. Objective: To assess the effects of a somatomotor proprioceptive training of the lower limbs, on CMC to muscles of upper and lower limbs and to elucidate the role of CMC as an indicator of training-induced functional changes. Methods: We examined CMC at frequencies between 10 and 35 Hz in 10 healthy male volunteers before and after a somatomotor leg training with emphasis on proprioception on a training platform on oscillating bearings with aperiodically damped elements. This training involved (1) standing with both feet on the resting platform, (2) stepping on the platform with one leg with subsequent stabilization and (3) standing on the resting platform with one leg and stabilization after dismantling the brakes of the platform due to a standardized protocol. Multichannel (60 channels) EEG recordings were obtained, while surface EMG was recorded from the following muscles of the dominant leg at a slight isometric contraction before and after the leg training: abductor pollicis brevis (APB), vastus lateral (VL) and vastus medial (VM) muscle. CMC pre- and post-intervention was computed at different frequency bands between 10– 12 Hz, 13–21 Hz, 22–30 Hz and 31–35 Hz, and was compared by using a General Linear Model. Results: CMC could be obtained in all subjects. The magnitude of CMC depended on the target muscle and on the frequency band. CMC magnitude involving recordings from leg muscles (CMC-VL and CMC-VM) was maximal at 31-35 Hz (similar between VL and
VM), whereas CMC involving recordings from APB (CMC-APB) was maximal at a frequency around 22–30 Hz. After intervention, CMCVL increased highly significantly between 31 and 35 Hz (GLM: F = 12.323, p = 0.001). CMC-APB also increased at 31–35 Hz (GLM: F = 6.929, p = 0.009), but significantly decreased at frequencies between 22 and 30 Hz (GLM: F = 4.882, p = 0.028). Conclusions: As changes of CMC are not limited to the training muscle alone, it appears unlikely that CMC is a physiological substrate of training-induced functional changes. Alternatively, changes of functional connectivity induced by leg training may be more widespread to include cortical control of upper limb muscles. doi:10.1016/j.clinph.2008.07.151
154. Matching midbrain-sonography to its macroanatomic correlate—D. Weise, R. Gentner, J. Claßen (Universität Würzburg, Neurologie, Würzburg, Germany) Introduction: Transcranial sonography (TCS) is a recently established neuroimaging technique that allows visualizing several brainstem structures including the substantia nigra (SN). Using TCS, an echogenic region can be detected at the suspected anatomical location of the SN, and this echogenic area amounts to around 0.12 cm2 in healthy controls. Although the location of SN-echogenicity is consistent with the location of the anatomical location, it remains unknown which part of SN is displayed because the rostro-caudal level of the 2-dimensional ultrasound plane in relation to the longitudinal axis of the SN has never been formally established.The relationship between the normal macroscopic anatomic extension of the SN and the extension of the echogenic SN-area is also not known. Methods: The anatomical extension of the SN was measured in the probabilistic atlas of the human brainstem published by Afshar and colleagues (Afshar F et al., New York: Raven Press; 1978). In all SN-containing sectional planes the SN was encircled manually and its spatial extension was quantified with The GIMP, a freely distributed computer program. TCS was performed with Sonoline Elegra (Siemens; Erlangen, Germany) in conjunction with a neuronavigation system (Brainsight, Rogue Research, Canada). Subjects were registered to template (or individual) MRI scans in order to monitor the corresponding anatomical section plane currently visualized with TCS. With the TCS-probe connected to the Brainsight system we used MR images of the subject as a real time guide of the position of the probe and illustration of the insonated plane. Results: The anatomical extension of the normal SN as assessed planimetrically varied substantially along its caudo-rostral axis, and it ranged from 0.27 to 0.46 cm2. The sonographic appearance of the brainstem best matched one of the three rostral-most sections of the atlas, located 8-10 mm rostrally from the caudal end of the SN. At these levels the anatomical area of the SN amounted to 0.44– 0.46 cm2. With this neuronavigated TCS the region of the SN was identified and the corresponding ultrasound image freezed for quantitative measurements. Very small changes of the angulation of the probe led to significant changes of the insonated plane and the illustrated structures. Discussion: Greater anatomic extension of the SN than echogenic SN-area suggests that only part of SN can be visualized. This provides a basis for detecting extensions of SN-echogenicity in Parkinson’s disease. SN is usually evaluated in the most rostral sections, where pathological changes are known to be relatively mild. Neuronavigated TCS may enhance the diagnostic yield of midbrain sonography. doi:10.1016/j.clinph.2008.07.152