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P291 Transcranial direct current stimulation modulates neurogenesis and microglia activation in the mouse brain
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Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
Results: In line with previous studies with young adults, GABA concentration change was lower in the anodal tDCS condition as compared to the sham tDCS condition. Resting state motor networks showed a reduced inter-hemispheric functional connectivity between left and right primary motor cortices during anodal tDCS compared to cathodal and sham tDCS. This observation is consistent with results in young and older adults that have assessed tDCSinduced alterations of inter-hemispheric functional connectivity during resting-state fMRI. Conclusion: Our study demonstrates tDCS-induced neuronal plasticity in healthy older adults. This observed reorganization of the functional architecture of the motor cortex is in line with recent tDCS studies in young adults, however, research results are still heterogeneous. In sum, our data suggests that anodal tDCS induced a functional decoupling of motor cortices, indicating a reversal of age-related effects on inter-hemispheric connectivity. doi:10.1016/j.clinph.2016.10.397
P290 Transcranial direct current stimulation over the left and the right prefrontal cortex differentially affects pattern recognition in language domain—K. Horváth *, Z. Zavecz, Z. Illyés, K. Janacsek, D. Nemeth (Eötvös Loránd University, Budapest, Hungary, Hungarian Academy of Sciencies, Budapest, Hungary) ⇑
Corresponding author.
Recognition of elements and patterns in the environment is an evolutionary fundamental ability of ours. These processes are crucial in decision making, learning and memory. The prefrontal cortex has a key role in recognition of patterns both in visual and language domain. The aim of the present study was to directly investigate the causal role of the left and the right PFC in pattern recognition in language domain. Twenty healthy young adults participated in the experiment. Transcranial direct current stimulation (tDCS) was used in order to modify the neural excitability of the targeted brain areas (F3 or F4). The reference electrode was placed over Cz. Performance was tested by a new, ecologically valid word search task. We used a within subject design in which all of the participants received 20-min, 2 mA left PFC anodal, right PFC anodal or sham stimulation through three sessions, one week apart from each other. Our results can lead to a deeper understanding of the role of the prefrontal cortex in pattern extraction in language domain and hemispheric differences in this essential process. doi:10.1016/j.clinph.2016.10.398
P291 Transcranial direct current stimulation modulates neurogenesis and microglia activation in the mouse brain—A. Pikhovych a,b, N. P. Stolberg a, H.L. Walter a, R. Graf b, G.R. Fink a,c, M. Schroeter a,b,c, M.A. Rueger a,b,c,* (a University Hospital of Cologne, Department of Neurology, Cologne, Germany, b Max Planck Institute for Metabolism Research, Cologne, Germany, c Institute of Neuroscience and Medicine, Cognitive Neuroscience, Juelich, Germany) ⇑
Corresponding author.
Transcranial direct current stimulation (tDCS) has been suggested as an adjuvant tool to promote recovery of function after stroke, but
the mechanisms of its action to date remain poorly understood. Moreover, studies aimed at unraveling those mechanisms have essentially been limited to the rat, where tDCS activates resident microglia as well as endogenous neural stem cells. Here we studied the effects of tDCS on microglia activation and neurogenesis in the mouse brain. Male wild-type mice were subjected to repetitive tDCS of either anodal or cathodal polarity; sham-stimulated mice served as control. Activated microglia in the cerebral cortex, and neuroblasts generated in the subventricular zone as the major neural stem cell niche, were assessed immunohistochemically. Repetitive tDCS at a sub-lesional charge density led to a polaritydependent downregulation of the constitutive expression of Iba1 by microglia in the mouse cortex. In contrast, both anodal and – to an even greater extent – cathodal tDCS induced neurogenesis from the subventricular zone. Data suggest that tDCS elicits its action through multi-facetted mechanisms, including immunomodulation and neurogenesis, and thus support the idea of using tDCS to induce regeneration and to promote recovery of function. Furthermore, data suggest that the effects of tDCS may be animal- and polarity-specific. doi:10.1016/j.clinph.2016.10.399
P292 10 Hz rTMS induces long-term depression of GABAergic neurotransmission—M. Lenz a,b,*, C. Galanis b, F. Müller-Dahlhaus c,d, A. Opitz e,f, C.J. Wierenga g, G. Szabó h, U. Ziemann c,d, T. Deller b, K. Funke i, A. Vlachos a,b (a Heinrich-Heine-University, Institute of Anatomy II, Faculty of Medicine, Düsseldorf, Germany, b GoetheUniversity, Institute of Clinical Neuroanatomy, Neuroscience Center, Frankfurt/Main, Germany , c Eberhard-Karls-University, Department of Neurology and Stroke, Tübingen, Germany , d Eberhard-Karls-University, Hertie Institute for Clinical Brain Research, Tübingen, Germany, e Nathan Kline Institute for Psychiatric Research, Center for Biomedical Imaging and Neuromodulation, Orangeburg, 10962 NY, United States, f Child Mind Institute New York, Center for the Developing Brain, 10022 New York, United States, g Utrecht University, Division of Cell Biology, Faculty of Science, Utrecht, Netherlands, h Institute of Experimental Medicine, Laboratory of Molecular Biology and Genetics, Budapest, Hungary, i Ruhr-University, Department of Neurophysiology, Medical Faculty, Bochum, Germany) ⇑
Corresponding author.
Question: The cellular and molecular mechanisms of rTMSinduced neural plasticity remain not well understood. Recent experimental evidence obtained in mouse brain slice cultures disclosed that 10 Hz repetitive magnetic stimulation (rMS) induces longterm potentiation (LTP) of excitatory neurotransmission. These studies support the notion that rTMS acts through the induction of ‘LTPlike’ plasticity. Here, we tested whether rTMS increases cortical excitability by mediating long-term depression (LTD) of inhibitory neurotransmission. Methods: Immunohistochemistry, fluorescence recovery after photobleaching, GABA-uncaging experiments and paired whole-cell patch clamp recordings were used in entorhino-hippocampal slice cultures to study the effects of 10 Hz rMS on structural and functional properties of inhibitory synapses of CA1 pyramidal neurons. Results: We report that 10 Hz rMS reduces dendritic but not somatic GABAergic neurotransmission onto CA1 pyramidal neurons. These functional changes are accompanied by structural remodeling of inhibitory postsynapses and depend on the activation of voltage
Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
Results: In line with previous studies with young adults, GABA concentration change was lower in the anodal tDCS condition as compared to the sham tDCS condition. Resting state motor networks showed a reduced inter-hemispheric functional connectivity between left and right primary motor cortices during anodal tDCS compared to cathodal and sham tDCS. This observation is consistent with results in young and older adults that have assessed tDCSinduced alterations of inter-hemispheric functional connectivity during resting-state fMRI. Conclusion: Our study demonstrates tDCS-induced neuronal plasticity in healthy older adults. This observed reorganization of the functional architecture of the motor cortex is in line with recent tDCS studies in young adults, however, research results are still heterogeneous. In sum, our data suggests that anodal tDCS induced a functional decoupling of motor cortices, indicating a reversal of age-related effects on inter-hemispheric connectivity. doi:10.1016/j.clinph.2016.10.397
P290 Transcranial direct current stimulation over the left and the right prefrontal cortex differentially affects pattern recognition in language domain—K. Horváth *, Z. Zavecz, Z. Illyés, K. Janacsek, D. Nemeth (Eötvös Loránd University, Budapest, Hungary, Hungarian Academy of Sciencies, Budapest, Hungary) ⇑
Corresponding author.
Recognition of elements and patterns in the environment is an evolutionary fundamental ability of ours. These processes are crucial in decision making, learning and memory. The prefrontal cortex has a key role in recognition of patterns both in visual and language domain. The aim of the present study was to directly investigate the causal role of the left and the right PFC in pattern recognition in language domain. Twenty healthy young adults participated in the experiment. Transcranial direct current stimulation (tDCS) was used in order to modify the neural excitability of the targeted brain areas (F3 or F4). The reference electrode was placed over Cz. Performance was tested by a new, ecologically valid word search task. We used a within subject design in which all of the participants received 20-min, 2 mA left PFC anodal, right PFC anodal or sham stimulation through three sessions, one week apart from each other. Our results can lead to a deeper understanding of the role of the prefrontal cortex in pattern extraction in language domain and hemispheric differences in this essential process. doi:10.1016/j.clinph.2016.10.398
P291 Transcranial direct current stimulation modulates neurogenesis and microglia activation in the mouse brain—A. Pikhovych a,b, N. P. Stolberg a, H.L. Walter a, R. Graf b, G.R. Fink a,c, M. Schroeter a,b,c, M.A. Rueger a,b,c,* (a University Hospital of Cologne, Department of Neurology, Cologne, Germany, b Max Planck Institute for Metabolism Research, Cologne, Germany, c Institute of Neuroscience and Medicine, Cognitive Neuroscience, Juelich, Germany) ⇑
Corresponding author.
Transcranial direct current stimulation (tDCS) has been suggested as an adjuvant tool to promote recovery of function after stroke, but
the mechanisms of its action to date remain poorly understood. Moreover, studies aimed at unraveling those mechanisms have essentially been limited to the rat, where tDCS activates resident microglia as well as endogenous neural stem cells. Here we studied the effects of tDCS on microglia activation and neurogenesis in the mouse brain. Male wild-type mice were subjected to repetitive tDCS of either anodal or cathodal polarity; sham-stimulated mice served as control. Activated microglia in the cerebral cortex, and neuroblasts generated in the subventricular zone as the major neural stem cell niche, were assessed immunohistochemically. Repetitive tDCS at a sub-lesional charge density led to a polaritydependent downregulation of the constitutive expression of Iba1 by microglia in the mouse cortex. In contrast, both anodal and – to an even greater extent – cathodal tDCS induced neurogenesis from the subventricular zone. Data suggest that tDCS elicits its action through multi-facetted mechanisms, including immunomodulation and neurogenesis, and thus support the idea of using tDCS to induce regeneration and to promote recovery of function. Furthermore, data suggest that the effects of tDCS may be animal- and polarity-specific. doi:10.1016/j.clinph.2016.10.399
P292 10 Hz rTMS induces long-term depression of GABAergic neurotransmission—M. Lenz a,b,*, C. Galanis b, F. Müller-Dahlhaus c,d, A. Opitz e,f, C.J. Wierenga g, G. Szabó h, U. Ziemann c,d, T. Deller b, K. Funke i, A. Vlachos a,b (a Heinrich-Heine-University, Institute of Anatomy II, Faculty of Medicine, Düsseldorf, Germany, b GoetheUniversity, Institute of Clinical Neuroanatomy, Neuroscience Center, Frankfurt/Main, Germany , c Eberhard-Karls-University, Department of Neurology and Stroke, Tübingen, Germany , d Eberhard-Karls-University, Hertie Institute for Clinical Brain Research, Tübingen, Germany, e Nathan Kline Institute for Psychiatric Research, Center for Biomedical Imaging and Neuromodulation, Orangeburg, 10962 NY, United States, f Child Mind Institute New York, Center for the Developing Brain, 10022 New York, United States, g Utrecht University, Division of Cell Biology, Faculty of Science, Utrecht, Netherlands, h Institute of Experimental Medicine, Laboratory of Molecular Biology and Genetics, Budapest, Hungary, i Ruhr-University, Department of Neurophysiology, Medical Faculty, Bochum, Germany) ⇑
Corresponding author.
Question: The cellular and molecular mechanisms of rTMSinduced neural plasticity remain not well understood. Recent experimental evidence obtained in mouse brain slice cultures disclosed that 10 Hz repetitive magnetic stimulation (rMS) induces longterm potentiation (LTP) of excitatory neurotransmission. These studies support the notion that rTMS acts through the induction of ‘LTPlike’ plasticity. Here, we tested whether rTMS increases cortical excitability by mediating long-term depression (LTD) of inhibitory neurotransmission. Methods: Immunohistochemistry, fluorescence recovery after photobleaching, GABA-uncaging experiments and paired whole-cell patch clamp recordings were used in entorhino-hippocampal slice cultures to study the effects of 10 Hz rMS on structural and functional properties of inhibitory synapses of CA1 pyramidal neurons. Results: We report that 10 Hz rMS reduces dendritic but not somatic GABAergic neurotransmission onto CA1 pyramidal neurons. These functional changes are accompanied by structural remodeling of inhibitory postsynapses and depend on the activation of voltage