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P215 Driving human motor cortical oscillations leads to behaviourally relevant changes in local GABA(A) Inhibition: A tACS-TMS study
Abstracts / Clinical Neurophysiology 128 (2017) e178–e303
muscular and cardiovascular dysfunctions, have received more attention recently. However, the effect of altered muscular strength on cardiovascular function. The current study examined the relationship of handgrip, leg, and arm strengths with central and peripheral cardiovascular function in PD. Methods: Blood pressure and vascular measures as well as handgrip, shoulder, and leg strengths were obtained in 29 PD persons and 30 healthy control (CT). Results: The data reveal that muscular and cardiovascular functions are altered (p < 0.05) in PD. Most importantly, regression indicates that altered central and peripheral cardiovascular function measures are related (p < 0.05) to deteriorated handgrip (R2range = 0.196–0.257), shoulder (R2-range = 0.146–0.289), and leg (R2-range = 0.19–0.35) strengths in PD. Discussion: These results suggest that deteriorated muscular strength and cardiovascular function are related. Additionally, developing muscular strength might contribute to improving cardiovascular function in PD. However, additional cross-sectional and longitudinal studies are warranted to confirm these findings and to verify these speculations. Conclusions: These results might suggest that improvement of muscular strength might contribute t to enhancing CV health. Significance: The study further confirm the importance of muscular strength for PD patients.
Keywords: Parkinson’s disease, Strength, Handgrip, Shoulder press, Leg extension, Cardiovascular doi:10.1016/j.clinph.2017.07.221
O214 Interdependence of heart and brain bioelectrical activity— Ewa Zalewska (Nalecz Institute of Biocybernetics and Biomedical Engineering, PAS, Department of Neuroengineering, Warsaw, Poland) Objectives: To study relationship between bioelectrical activity of brain and heart. The aim was to extract components related to heart activity in multichannel EEG recordings of healthy subjects. Methods: The studied group consisted of 20 healthy subjects in age 20–32 yrs. Bioelectrical activity of the brain, electrooculography (HEOG and VEOG), respiratory signal and ECG from V5 derivation were recorded. In EEG signal an ECGEEG component related to the action of heart and one related to the interactions between the electric fields of heart and brain were extracted. The variations of the ECGEEG potential during the heart beat cycle were mapped. Results: In the study group the topographic distribution of the ECGEEG potential had a cyclic change during the heart beat cycle. ECGEEG component revealed differences in polarity and amplitude as well as asymmetrical topographic distribution. The series of consecutive maps indicate asymmetry with anti-clockwise rotation. Conclusions: The results indicate the significant, simultaneous changes of the analysed parameters of the EEG and ECG signals which suggests that they can be considered as indicators of the interaction between the autonomic and the central nervous systems. Significance: Investigations of the relationship between the bioelectrical activities of heart and brain allow to expand the diagnostic capabilities of EEG and ECG, especially in the differential diagnosis of the neurologic and cardiologic diseases.
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Poster I. – Brain Stimulation I P215 Driving human motor cortical oscillations leads to behaviourally relevant changes in local GABA(A) Inhibition: A TACSTMS study—Magdalena Nowak 1, Emily Hinson 1, Freek Van Ede 2, Alek Pogosyan 3, Andrea Guerra 4, Andrew Quinn 2, Peter Brown 3, Charlotte Stagg 1 (1 University of Oxford, Nuffield Department of Clinical Neurosciences, Oxford, United Kingdom, 2 University of Oxford, Department of Psychiatry, Oxford, United Kingdom, 3 University of Oxford, MRC Brain Network Dynamics Unit, Oxford, United Kingdom, 4 Sapienza University of Rome, Department of Neurology and Psychiatry, Rome, Italy) Objectives: Beta and gamma oscillations are the dominant oscillatory activity in the human motor cortex (M1). However, their physiological basis and precise functional significance remain poorly understood. To this end, we employed Transcranial Magnetic Stimulation (TMS) to examine the physiological basis and behavioural relevance of driving beta and gamma oscillatory activity in the human M1 using transcranial alternating current stimulation (tACS). Methods: 20 healthy volunteers participated in four experimental sessions separated by at least 1 week. In Session 1, all subjects had a MEG scan in order to determine individual beta and gamma peak frequency for subsequent tACS sessions. In Sessions 2–4, subjects received tACS at beta frequency (20 Hz), gamma frequency (75 Hz) or sham stimulation. tACS was applied for 20 min over the left M1 and the contralateral orbit at individualised intensity. TMS measures (a single MEP, SICI and ICF) were performed at rest and during movement preparation. Results: Gamma tACS led to a significant, duration-dependent decrease in local resting-state GABA(A) inhibition (p = 0.002), as quantified by SICI. The magnitude of this effect was positively correlated with the magnitude of GABA(A) decrease during movement preparation (p = 0.003), when gamma activity in motor circuitry is known to increase. In addition, gamma tACS-induced change in GABA(A) inhibition was closely related to performance in a motor learning task, such that subjects who demonstrated a greater increase in GABA(A) inhibition also showed faster short-term learning (p < 0.001). Discussion and conclusions: Our findings show that gamma tACS is capable of modulating GABA(A) inhibition in M1 in a behaviourally relevant manner and suggest that tACS may have similar physiological effects to endogenously driven local oscillatory activity. Significance: This study contributes to our understanding of the neurophysiological basis of motor rhythms and their behavioural relevance. Moreover, the ability to modulate local interneuronal circuits by tACS in a behaviourally relevant manner provides a basis for tACS as a putative therapeutic intervention. Keywords: Cortical excitability, GABA, Oscillations, Non-invasive brain stimulation doi:10.1016/j.clinph.2017.07.223
P216 The efficacy of repetitive transcranial magnetic stimulation in treating patients with chronic daily headache—Ann Abdel Kader 1, Ebtesam Fahmy 2, Ayatullah Ahmad 1, Amira Labib 1,*, Leqaa Elmekkawy 1 (1 Cairo University, Department of Clinical Neurophysiology, Cairo, Egypt, 2 Cairo University, Department of Neurology, Cairo, Egypt)
Keywords: EEG, ECG doi:10.1016/j.clinph.2017.07.222
Objectives: Headache is the most prevalent pain disorder, affecting around 66% of the global population. This study aimed to investigate the efficacy of high-frequency repetitive transcranial magnetic
muscular and cardiovascular dysfunctions, have received more attention recently. However, the effect of altered muscular strength on cardiovascular function. The current study examined the relationship of handgrip, leg, and arm strengths with central and peripheral cardiovascular function in PD. Methods: Blood pressure and vascular measures as well as handgrip, shoulder, and leg strengths were obtained in 29 PD persons and 30 healthy control (CT). Results: The data reveal that muscular and cardiovascular functions are altered (p < 0.05) in PD. Most importantly, regression indicates that altered central and peripheral cardiovascular function measures are related (p < 0.05) to deteriorated handgrip (R2range = 0.196–0.257), shoulder (R2-range = 0.146–0.289), and leg (R2-range = 0.19–0.35) strengths in PD. Discussion: These results suggest that deteriorated muscular strength and cardiovascular function are related. Additionally, developing muscular strength might contribute to improving cardiovascular function in PD. However, additional cross-sectional and longitudinal studies are warranted to confirm these findings and to verify these speculations. Conclusions: These results might suggest that improvement of muscular strength might contribute t to enhancing CV health. Significance: The study further confirm the importance of muscular strength for PD patients.
Keywords: Parkinson’s disease, Strength, Handgrip, Shoulder press, Leg extension, Cardiovascular doi:10.1016/j.clinph.2017.07.221
O214 Interdependence of heart and brain bioelectrical activity— Ewa Zalewska (Nalecz Institute of Biocybernetics and Biomedical Engineering, PAS, Department of Neuroengineering, Warsaw, Poland) Objectives: To study relationship between bioelectrical activity of brain and heart. The aim was to extract components related to heart activity in multichannel EEG recordings of healthy subjects. Methods: The studied group consisted of 20 healthy subjects in age 20–32 yrs. Bioelectrical activity of the brain, electrooculography (HEOG and VEOG), respiratory signal and ECG from V5 derivation were recorded. In EEG signal an ECGEEG component related to the action of heart and one related to the interactions between the electric fields of heart and brain were extracted. The variations of the ECGEEG potential during the heart beat cycle were mapped. Results: In the study group the topographic distribution of the ECGEEG potential had a cyclic change during the heart beat cycle. ECGEEG component revealed differences in polarity and amplitude as well as asymmetrical topographic distribution. The series of consecutive maps indicate asymmetry with anti-clockwise rotation. Conclusions: The results indicate the significant, simultaneous changes of the analysed parameters of the EEG and ECG signals which suggests that they can be considered as indicators of the interaction between the autonomic and the central nervous systems. Significance: Investigations of the relationship between the bioelectrical activities of heart and brain allow to expand the diagnostic capabilities of EEG and ECG, especially in the differential diagnosis of the neurologic and cardiologic diseases.
e247
Poster I. – Brain Stimulation I P215 Driving human motor cortical oscillations leads to behaviourally relevant changes in local GABA(A) Inhibition: A TACSTMS study—Magdalena Nowak 1, Emily Hinson 1, Freek Van Ede 2, Alek Pogosyan 3, Andrea Guerra 4, Andrew Quinn 2, Peter Brown 3, Charlotte Stagg 1 (1 University of Oxford, Nuffield Department of Clinical Neurosciences, Oxford, United Kingdom, 2 University of Oxford, Department of Psychiatry, Oxford, United Kingdom, 3 University of Oxford, MRC Brain Network Dynamics Unit, Oxford, United Kingdom, 4 Sapienza University of Rome, Department of Neurology and Psychiatry, Rome, Italy) Objectives: Beta and gamma oscillations are the dominant oscillatory activity in the human motor cortex (M1). However, their physiological basis and precise functional significance remain poorly understood. To this end, we employed Transcranial Magnetic Stimulation (TMS) to examine the physiological basis and behavioural relevance of driving beta and gamma oscillatory activity in the human M1 using transcranial alternating current stimulation (tACS). Methods: 20 healthy volunteers participated in four experimental sessions separated by at least 1 week. In Session 1, all subjects had a MEG scan in order to determine individual beta and gamma peak frequency for subsequent tACS sessions. In Sessions 2–4, subjects received tACS at beta frequency (20 Hz), gamma frequency (75 Hz) or sham stimulation. tACS was applied for 20 min over the left M1 and the contralateral orbit at individualised intensity. TMS measures (a single MEP, SICI and ICF) were performed at rest and during movement preparation. Results: Gamma tACS led to a significant, duration-dependent decrease in local resting-state GABA(A) inhibition (p = 0.002), as quantified by SICI. The magnitude of this effect was positively correlated with the magnitude of GABA(A) decrease during movement preparation (p = 0.003), when gamma activity in motor circuitry is known to increase. In addition, gamma tACS-induced change in GABA(A) inhibition was closely related to performance in a motor learning task, such that subjects who demonstrated a greater increase in GABA(A) inhibition also showed faster short-term learning (p < 0.001). Discussion and conclusions: Our findings show that gamma tACS is capable of modulating GABA(A) inhibition in M1 in a behaviourally relevant manner and suggest that tACS may have similar physiological effects to endogenously driven local oscillatory activity. Significance: This study contributes to our understanding of the neurophysiological basis of motor rhythms and their behavioural relevance. Moreover, the ability to modulate local interneuronal circuits by tACS in a behaviourally relevant manner provides a basis for tACS as a putative therapeutic intervention. Keywords: Cortical excitability, GABA, Oscillations, Non-invasive brain stimulation doi:10.1016/j.clinph.2017.07.223
P216 The efficacy of repetitive transcranial magnetic stimulation in treating patients with chronic daily headache—Ann Abdel Kader 1, Ebtesam Fahmy 2, Ayatullah Ahmad 1, Amira Labib 1,*, Leqaa Elmekkawy 1 (1 Cairo University, Department of Clinical Neurophysiology, Cairo, Egypt, 2 Cairo University, Department of Neurology, Cairo, Egypt)
Keywords: EEG, ECG doi:10.1016/j.clinph.2017.07.222
Objectives: Headache is the most prevalent pain disorder, affecting around 66% of the global population. This study aimed to investigate the efficacy of high-frequency repetitive transcranial magnetic