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P307 Demonstration of short-term plasticity in the dorsolateral prefrontal cortex with theta burst stimulation: A TMS-egg study
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Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
Figure 1.
astrocytes and a subpopulation of excitatory neurons, we find that tDCS induces large-amplitude astrocytic Ca2+ surges across the entire cortex with no obvious changes in the local field potential. Moreover, sensory evoked cortical responses are enhanced after tDCS. These enhancements are dependent on the alpha-1 adrenergic receptor (A1AR) and are not observed in IP3R2 (inositol trisphosphate receptor type 2) knockout mice, in which astrocytic Ca2+ surges are absent. Together, we propose that tDCS changes the metaplasticity of the cortex through astrocytic Ca2+/IP3 signalling. Moreover, the stimulation parameters were found to be sufficient to alleviate a mouse model of depression by chronic restraint stress.
schizophrenia. In developing clinical applications in such psychiatric illnesses, there is a need to explore whether the same effects on corticospinal excitability are achieved in non-motor regions. Objectives: The study aimed to examine the effects of iTBS and cTBS on cortical excitability in the dorsolateral prefrontal cortex, a brain region relevant to the treatment of a number of neuropsychiatric disorders. We hypothesized that iTBS and cTBS protocol would increase and decrease cortical excitability respectively.
Figure 1.
doi:10.1016/j.clinph.2016.10.413
P307 Demonstration of short-term plasticity in the dorsolateral prefrontal cortex with theta burst stimulation: A TMS-egg study— S.W. Chung a,*, B.P. Lewis a, N.C. Rogasch b, S. Takashi a, R. Thomson a, N.W. Bailey b, K.E. Hoy a, P.B. Fitzgerald a (a Monash University (Monash Alfred Psychiatry research centre), Central Clinical School, Melbourne, Australia, b Monash University, Brain and Mental Health Laboratory, School of Psychological Sciences and Monash Biomedical Imaging, Melbourne, Australia) ⇑
Corresponding author.
Introduction: Repetitive transcranial magnetic stimulation has the unique ability to modulate cortical activity. In particular, theta burst stimulation (TBS) has gained notable attention due to its efficacy in short stimulation durations. Vast majority of TBS studies have demonstrated corticospinal excitability change, however we know very little about the effects of TBS on cortical excitability outside of the motor cortex. There is increasing interest in the use of TBS as a therapeutic tool for disorders such as depression and
Theta power difference over time from 25 ms to 300 ms with 25 ms interval. Asterisks indicate statistical significance between iTBS and cTBS, round dots between iTBS and sham (p < .05).Topoplots show the differences are strongest at the frontal electrodes, including F3.
Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
Materials & methods: 10 healthy participants were stimulated with either iTBS, cTBS or sham on F3 electrode over 3 different sessions. TMS-EEG was used to assess cortical excitability change via TMS-evoked potentials (TEPs) and TMS-evoked oscillations. Results: Analysis on F3 revealed increase in N120 amplitude (p = .009) from pre to post iTBS. Cluster-based statistics showed one significant negative cluster at N120 (p = .003), indicating increased amplitude at the site of stimulation and contralaterally. TBS-induced changes (post - pre) were calculated and compared among different TBS conditions. N120 amplitude post iTBS was higher than cTBS at F3 (p = .042). TMS-evoked oscillations were significantly increased after iTBS in theta frequency at F3 from 50 to 250 ms (p = .044). TMS-evoked oscillations among different TBS at F3 yielded higher theta power after iTBS compared to cTBS and sham (p < .05; Fig. 1). Conclusion: This study provides some of the first evidence that TBS produces direct changes in cortical excitability in the prefrontal cortex. This may be a useful approach to optimise stimulation paradigms prior to the conduct of clinical trials. doi:10.1016/j.clinph.2016.10.414
P308 The effects of cerebellar trans-cranial direct current stimulation on neural network dynamics in supraspinal motor circuits during motor adaptation in cats—H.T. Darch *, N.L. Cerminara, R. Apps (University of Bristol, Bristol, United Kingdom) ⇑
Corresponding author.
Recent studies of trans-cranial Direct Current stimulation (tDCS) have raised the possibility that this is a relatively simple and well tolerated method that can be used as an effective therapeutic tool to treat neurological and neuropsychiatric disorders (Grimaldir et al., 2016). In particular, stimulation of the cerebellum (ctDCS) in humans has been shown to modulate a wide range of functions, including motor learning and working memory (Grimaldir et al., 2014). Despite the increasing use of this method, there are still important knowledge gaps and controversies regarding the physiological effects of ctDCS and the underlying neurobiological basis of any effects remains unknown. We have examined the effects of anodal, and cathodal ctDCS on the electrophysiological activity in the supraspinal motor network (SMN) during prism motor adaptation of a skilled, goal-directed movement in cats. Preliminary frequency domain analysis of the local field potential recorded simultaneously in cerebellar cortex (lobule V, proximal to the ctDCS electrode), primary motor cortex, and pre-frontal cortex suggests variable effects of ctDCS on neuronal population activity and changes in coherence between different sites in the SMN during motor adaptation.
References Grimaldi G et al. Cerebellum 2014;13(1):121–38. Grimaldi G et al. Neuroscientist 2016;22(1):83–97. doi:10.1016/j.clinph.2016.10.415
P309 Pulsed electromagnetic field (PEMF) improves microcirculation and reduces hypoxia and neuronal death in a hypertensive rat
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brain—D. Bragin *, O. Bragina, G. Statom, S. Hagberg, E. Nemoto (University of New Mexico School of Medicine, Neurosurgery, Albuquerque, United States) ⇑
Corresponding author.
Introduction: We previously showed that pulsed electromagnetic field (PEMF) increased microvascular blood flow and tissue oxygenation by nitric oxide-induced vasodilation in a healthy rat brain (Bragin et al., 2015). We also showed that high intracranial pressure (ICP) in rats caused a transition from capillary (CAP) to non-nutritive microvascular shunt (MVS) flow, tissue hypoxia and blood brain barrier (BBB) degradation (Bragin et al., 2011). Objectives: To evaluate whether PEMF attenuates the detrimental effects of non-nutritive MVS flow induced by high ICP. Materials and methods: By in vivo 2-photon laser scanning microscopy over the rat parietal cortex, we evaluated the effects of PEMF on microvascular blood flow, tissue oxygenation (NADH), BBB permeability (dye extravasation) and neuronal necrosis (i.v. propidium Iodide) during 4 h of high ICP. Doppler cortical flux, rectal and cranial temperatures, ICP and arterial pressure, blood gases and electrolytes were monitored. After baseline imaging at normal ICP (10 mmHg), rats were subjected to high ICP (30 mmHg) by raising an artificial cerebrospinal fluid reservoir connected to the cisterna magna. At ICP of 30 mmHg, PEMF was applied for 30 min and imaging continuously performed after the treatment. Controls were untreated with PEMF. Results: PEMF decreased tissue hypoxia (NADH reduced by 14.6 ± 3.7% compared to control, n = 10 rats per group, mean ± SEM, p < 0.05). BBB damage progression was reduced as reflected by less by 17.2 ± 5.4% dye extravasation (p < 0.05). Decreased by PEMF hypoxia reduced neuronal necrosis (15 ± 3.6% in PEMF vs. 26 ± 6.2% in control, p < 0.05), consistent with dilation of arterioles (+4.5 ± 3.2%) and an increase in capillary blood flow velocity (+4.7 ± 3.2%). PEMF did not completely mitigate the gradual increase in MVS flow at but, as reflected by MVS/capillary ratio, the transition to non-nutritive flow was reduced in the PEMF compared to the untreated rats (2.3 ± 1.1 and 3.8 ± 2.1% change per hour, respectively, p < 0.05). Conclusions: PEMF reduced tissue hypoxia, BBB degradation and neuronal necrosis by modulating cerebral blood flow at high ICP. PEMF could be an effective treatment for high ICP after severe cerebral insults. Support: Rio Grande Neurosciences. References Bragin et al, J. Neurosurgery, 2015. Bragin et al, J. Neurotrauma, 2011. doi:10.1016/j.clinph.2016.10.416
P310 Brain stimulation-induced neuroplasticity underlying therapeutic response in phantom sounds—T. Poeppl a,b,*, B. Langguth a,b, A. Lehner a,b, R. Rupprecht a, P. Kreuzer a,b, M. Landgrebe a,c, M. Schecklmann a,b (a University of Regensburg, Department of Psychiatry and Psychotherapy, Regensburg, Germany, b University of Regensburg, Tinnitus Center, Regensburg, Germany, c Lech Mangfall Hospital, Department of Psychiatry and Psychotherapyartment of Psychiatry and Psychotherapy, Agatharied, Germany) ⇑
Corresponding author.
Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
Figure 1.
astrocytes and a subpopulation of excitatory neurons, we find that tDCS induces large-amplitude astrocytic Ca2+ surges across the entire cortex with no obvious changes in the local field potential. Moreover, sensory evoked cortical responses are enhanced after tDCS. These enhancements are dependent on the alpha-1 adrenergic receptor (A1AR) and are not observed in IP3R2 (inositol trisphosphate receptor type 2) knockout mice, in which astrocytic Ca2+ surges are absent. Together, we propose that tDCS changes the metaplasticity of the cortex through astrocytic Ca2+/IP3 signalling. Moreover, the stimulation parameters were found to be sufficient to alleviate a mouse model of depression by chronic restraint stress.
schizophrenia. In developing clinical applications in such psychiatric illnesses, there is a need to explore whether the same effects on corticospinal excitability are achieved in non-motor regions. Objectives: The study aimed to examine the effects of iTBS and cTBS on cortical excitability in the dorsolateral prefrontal cortex, a brain region relevant to the treatment of a number of neuropsychiatric disorders. We hypothesized that iTBS and cTBS protocol would increase and decrease cortical excitability respectively.
Figure 1.
doi:10.1016/j.clinph.2016.10.413
P307 Demonstration of short-term plasticity in the dorsolateral prefrontal cortex with theta burst stimulation: A TMS-egg study— S.W. Chung a,*, B.P. Lewis a, N.C. Rogasch b, S. Takashi a, R. Thomson a, N.W. Bailey b, K.E. Hoy a, P.B. Fitzgerald a (a Monash University (Monash Alfred Psychiatry research centre), Central Clinical School, Melbourne, Australia, b Monash University, Brain and Mental Health Laboratory, School of Psychological Sciences and Monash Biomedical Imaging, Melbourne, Australia) ⇑
Corresponding author.
Introduction: Repetitive transcranial magnetic stimulation has the unique ability to modulate cortical activity. In particular, theta burst stimulation (TBS) has gained notable attention due to its efficacy in short stimulation durations. Vast majority of TBS studies have demonstrated corticospinal excitability change, however we know very little about the effects of TBS on cortical excitability outside of the motor cortex. There is increasing interest in the use of TBS as a therapeutic tool for disorders such as depression and
Theta power difference over time from 25 ms to 300 ms with 25 ms interval. Asterisks indicate statistical significance between iTBS and cTBS, round dots between iTBS and sham (p < .05).Topoplots show the differences are strongest at the frontal electrodes, including F3.
Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
Materials & methods: 10 healthy participants were stimulated with either iTBS, cTBS or sham on F3 electrode over 3 different sessions. TMS-EEG was used to assess cortical excitability change via TMS-evoked potentials (TEPs) and TMS-evoked oscillations. Results: Analysis on F3 revealed increase in N120 amplitude (p = .009) from pre to post iTBS. Cluster-based statistics showed one significant negative cluster at N120 (p = .003), indicating increased amplitude at the site of stimulation and contralaterally. TBS-induced changes (post - pre) were calculated and compared among different TBS conditions. N120 amplitude post iTBS was higher than cTBS at F3 (p = .042). TMS-evoked oscillations were significantly increased after iTBS in theta frequency at F3 from 50 to 250 ms (p = .044). TMS-evoked oscillations among different TBS at F3 yielded higher theta power after iTBS compared to cTBS and sham (p < .05; Fig. 1). Conclusion: This study provides some of the first evidence that TBS produces direct changes in cortical excitability in the prefrontal cortex. This may be a useful approach to optimise stimulation paradigms prior to the conduct of clinical trials. doi:10.1016/j.clinph.2016.10.414
P308 The effects of cerebellar trans-cranial direct current stimulation on neural network dynamics in supraspinal motor circuits during motor adaptation in cats—H.T. Darch *, N.L. Cerminara, R. Apps (University of Bristol, Bristol, United Kingdom) ⇑
Corresponding author.
Recent studies of trans-cranial Direct Current stimulation (tDCS) have raised the possibility that this is a relatively simple and well tolerated method that can be used as an effective therapeutic tool to treat neurological and neuropsychiatric disorders (Grimaldir et al., 2016). In particular, stimulation of the cerebellum (ctDCS) in humans has been shown to modulate a wide range of functions, including motor learning and working memory (Grimaldir et al., 2014). Despite the increasing use of this method, there are still important knowledge gaps and controversies regarding the physiological effects of ctDCS and the underlying neurobiological basis of any effects remains unknown. We have examined the effects of anodal, and cathodal ctDCS on the electrophysiological activity in the supraspinal motor network (SMN) during prism motor adaptation of a skilled, goal-directed movement in cats. Preliminary frequency domain analysis of the local field potential recorded simultaneously in cerebellar cortex (lobule V, proximal to the ctDCS electrode), primary motor cortex, and pre-frontal cortex suggests variable effects of ctDCS on neuronal population activity and changes in coherence between different sites in the SMN during motor adaptation.
References Grimaldi G et al. Cerebellum 2014;13(1):121–38. Grimaldi G et al. Neuroscientist 2016;22(1):83–97. doi:10.1016/j.clinph.2016.10.415
P309 Pulsed electromagnetic field (PEMF) improves microcirculation and reduces hypoxia and neuronal death in a hypertensive rat
e161
brain—D. Bragin *, O. Bragina, G. Statom, S. Hagberg, E. Nemoto (University of New Mexico School of Medicine, Neurosurgery, Albuquerque, United States) ⇑
Corresponding author.
Introduction: We previously showed that pulsed electromagnetic field (PEMF) increased microvascular blood flow and tissue oxygenation by nitric oxide-induced vasodilation in a healthy rat brain (Bragin et al., 2015). We also showed that high intracranial pressure (ICP) in rats caused a transition from capillary (CAP) to non-nutritive microvascular shunt (MVS) flow, tissue hypoxia and blood brain barrier (BBB) degradation (Bragin et al., 2011). Objectives: To evaluate whether PEMF attenuates the detrimental effects of non-nutritive MVS flow induced by high ICP. Materials and methods: By in vivo 2-photon laser scanning microscopy over the rat parietal cortex, we evaluated the effects of PEMF on microvascular blood flow, tissue oxygenation (NADH), BBB permeability (dye extravasation) and neuronal necrosis (i.v. propidium Iodide) during 4 h of high ICP. Doppler cortical flux, rectal and cranial temperatures, ICP and arterial pressure, blood gases and electrolytes were monitored. After baseline imaging at normal ICP (10 mmHg), rats were subjected to high ICP (30 mmHg) by raising an artificial cerebrospinal fluid reservoir connected to the cisterna magna. At ICP of 30 mmHg, PEMF was applied for 30 min and imaging continuously performed after the treatment. Controls were untreated with PEMF. Results: PEMF decreased tissue hypoxia (NADH reduced by 14.6 ± 3.7% compared to control, n = 10 rats per group, mean ± SEM, p < 0.05). BBB damage progression was reduced as reflected by less by 17.2 ± 5.4% dye extravasation (p < 0.05). Decreased by PEMF hypoxia reduced neuronal necrosis (15 ± 3.6% in PEMF vs. 26 ± 6.2% in control, p < 0.05), consistent with dilation of arterioles (+4.5 ± 3.2%) and an increase in capillary blood flow velocity (+4.7 ± 3.2%). PEMF did not completely mitigate the gradual increase in MVS flow at but, as reflected by MVS/capillary ratio, the transition to non-nutritive flow was reduced in the PEMF compared to the untreated rats (2.3 ± 1.1 and 3.8 ± 2.1% change per hour, respectively, p < 0.05). Conclusions: PEMF reduced tissue hypoxia, BBB degradation and neuronal necrosis by modulating cerebral blood flow at high ICP. PEMF could be an effective treatment for high ICP after severe cerebral insults. Support: Rio Grande Neurosciences. References Bragin et al, J. Neurosurgery, 2015. Bragin et al, J. Neurotrauma, 2011. doi:10.1016/j.clinph.2016.10.416
P310 Brain stimulation-induced neuroplasticity underlying therapeutic response in phantom sounds—T. Poeppl a,b,*, B. Langguth a,b, A. Lehner a,b, R. Rupprecht a, P. Kreuzer a,b, M. Landgrebe a,c, M. Schecklmann a,b (a University of Regensburg, Department of Psychiatry and Psychotherapy, Regensburg, Germany, b University of Regensburg, Tinnitus Center, Regensburg, Germany, c Lech Mangfall Hospital, Department of Psychiatry and Psychotherapyartment of Psychiatry and Psychotherapy, Agatharied, Germany) ⇑
Corresponding author.