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P298 Effects of cerebellar transcranial direct-current stimulation on cerebellar sensory-induced LFPs and Purkinje cell activity in alert mice
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Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
Figure 2.
TRSP plots of the TMS-induced oscillatory activity over DLPFC before (left panels) and after (right panels) FP-PAS (upper panels) and PF-PAS (lower panels). A PAS-dependent modulation of oscillatory activity is appreciable, specifically FP-PAS produced an increase of TRSP values whether PF-PAS resulted in the opposite effect. doi:10.1016/j.clinph.2016.10.404
P297 Sensory plasticity changes induced by somatosensory and cerebellar tDCS in alert mice—J. Márquez-Ruiz a,*, C.A. Sánchez-León a, J. Ausín-Azofra b, C. Ammann c, A. Gruart a, J. Delgado-García a (a University Pablo de Olavide, Division of Neurosciences, Seville, Spain, b Laboratorio Europeo de Neurotecnologías Inmersivas, Instituto Labhuman, Valencia, Spain, c Johns Hopkins Medical Institution, Department of Physical Medicine and Rehbilitation, Baltimore, Spain) ⇑
Corresponding author.
Introduction: During the past years, new evidence has revealed the importance of the cerebellar-brain-inhibition (CBI) pathway on cognitive and sensory processing. The modulation of the cerebellar cortex through non-invasive stimulation techniques, as transcranial direct-current stimulation (tDCS), could contribute to the better understanding of neuronal mechanisms underlying the implication of cerebellar cortex in these processes. Objectives: The aim of this study was to explore cerebro-cerebellar interactions affecting long-term plasticity in the somatosensory (SS) cortex by modulating cerebral and cerebellar cortical excitability in behaving mice. Materials and methods: Mice were prepared for the chronic recording of local field potentials (LFPs) in the SS cortex in response to electrical whisker pad stimulation, as well as for simultaneous tDCS. Animals received tDCS over the cerebellum or the SS cortex at different current intensities with a duration of 5 s to asses immediate effects, and during 20 min to address after-effects on SS-LFPs. tDCS effects on long-term plasticity processes in the SS cortex were determined by using two conditioning protocols consisting of 8 and 50 Hz whisker stimulation with a duration of 10 min and 96 s, respectively. Each protocol was combined with the simultaneous presentation of tDCS or sham condition. Results: Anodal increased and cathodal decreased in an immediate way the amplitude of SS-LFPs when applied to the ipsilateral SS cortex, whereas the opposite effects were obtained when tDCS was
presented to the contralateral cerebellar cortex. Concerning longterm after-effects, cathodal tDCS over the SS cortex induced a long-term depression of LFPs whereas no effects were observed after anodal currents. Long-term potentiation of SS-LFPs was evoked by both cathodal and anodal cerebellar tDCS. Finally and as expected, long-term depression and long-term potentiation of SS-LFPs induced by 8 and 50 Hz whisker stimulation were modulated by simultaneous cerebellar tDCS. Conclusions: The results demonstrate the capability of tDCS to modulate the excitability of SS and cerebellar cortices, as well as the potential role of the cerebellar cortex in the control of plastic changes occurring in the sensory cortex of behaving animals. doi:10.1016/j.clinph.2016.10.405
P298 Effects of cerebellar transcranial direct-current stimulation on cerebellar sensory-induced LFPs and Purkinje cell activity in alert mice—C.A. Sánchez-León a, M. Gómez-Climent a, A. Jiménez-Díaz a, J. Delgado-García a, G. Cheron b,c, J. Márquez-Ruiz a,* (a University Pablo de Olavide, Division of Neurosciences, Seville, Spain, b Université de Mons, Laboratory of Electrophysiology, Mons, Belgium, c Université Libre de Bruxelles, Laboratory of Neurophysiology and Movement Biomechanics, Brussels, Belgium) ⇑
Corresponding author.
Introduction: During last years the putative effects of cerebellar transcranial direct-current stimulation (tDCS) has attracted the attention of basic and clinical neuroscientist. Nevertheless, the impact of exogenous electric fields on the different components of the cerebellar network is not already elucidated. Objectives: The aim of this study was to characterize physiological mechanisms underlying short- and long-term effects associated to cerebellar tDCS in alert behaving mice. In particular, we explored the tDCS impact on the cerebellar response to sensory inputs (whisker stimulation) and the potential modulation of Purkinje Cell (PC) discharge rates.
Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
e157
Figure 1.
Materials & methods: Mice were prepared for chronic recording of local field potentials (LFPs) and PC firing in the CrusI/II region of the cerebellum. Along the experimental sessions spontaneous and stimulus-induced (by electrical whisker pad stimulation) activity of PCs (identified by the presence of simple and complex spikes) were recorded before, during and after anodal and cathodal tDCS applied over the cerebellum. For that, we used ring-electrodes placed over the skull allowing simultaneous tDCS stimulation and glass micropipette insertion for LFPs and extracellular unitary recording. tDCS was performed at different current intensities for 5 s to test the immediate effects on sensory-related LFPs and PC activity, and during 20 min to show after-effects on sensory related LFPs. Results: Regarding to the immediate short-term effects (5 s), anodal and cathodal cerebellar tDCS increased and decreased, respectively, the amplitude of N3 component of LFPs induced by simultaneous whisker stimulation. This component has been previously reported to reflect the synaptic activity between parallel fiber and the dendritic tree of PC. Interestingly, longer stimulation sessions (20 min) induced long-term effects that last for more than one hour. Coherently, the firing rate of identified PC was increased or decreased depending of the anodal or cathodal tDCS, respectively. PC response to whisker tactile stimulation was also modulated in the same manner. Conclusions: Present results demonstrate tDCS’s capability for short- and long-term modulation of the cerebellar cortex, and specifically PCs firing activities.
Figure 2.
doi:10.1016/j.clinph.2016.10.406
P299 Inter-individual variability and intra-individual reliability of iTBS-induced neuroplasticity mechanisms in the healthy brain— L. Schilberg *, T. Schuhmann, A.T. Sack (Maastricht University, Cognitive Neuroscience, Maastricht, Netherlands) ⇑
Corresponding author.
Introduction: Neuroplasticity refers to either cortical reorganization or changes in synaptic efficacy between neurons. We combined patterned TMS (iTBS) with electromyography (EMG) to assess and characterize inter-individual variability and intra-individual reliability of TMS-induced neuroplasticity mechanisms in the healthy brain. In the future, reliable measures of TMS-induced neuroplasticity mechanisms could serve as early biomarkers of aberrant cortical neuroplasticity and they could help to guide therapeutic progress of affected individuals. Objectives: To investigate both (1) inter-individual variability and (2) intra-individual reliability of iTBS-induced changes in corticospinal excitability, and (3) the association of individual prolonged measures of corticospinal excitability with iTBS-induced changes in motor evoked potential (MEP) amplitudes. Patients & methods: We applied iTBS over the primary motor cortex (M1) to induce LTP-like mechanisms in fourteen participants on two separate visits and we used EMG from the first dorsal interosseous (FDI) muscle to measure changes in TMS-elicited MEP amplitudes over sixty minutes. We applied sham-iTBS to measure unmodulated prolonged corticospinal excitability. Results: Over a grand period of sixty minutes iTBS led to a group increase of corticospinal excitability, whereas sham-iTBS had no modulatory effects. This increase was reduced on a second measurement (Fig. 1) and individual measures had low reliability (Fig. 2). Furthermore, individual measures of corticospinal excitability over a prolonged time period (sham-visit) of up to sixty minutes were
not associated with the measures of iTBS-induced changes in MEP amplitude of both stimulation visits. Conclusion: At the group level iTBS over M1 has a facilitatory effect on corticospinal excitability. However, this group effect appears to weaken during a second assessment. Furthermore, we find that there is high inter-individual variability and low intra-individual reliability of the observed iTBS-induced neuroplasticity measures. This creates great challenges for the interpretation of group iTBS effects on corticospinal excitability and it is thus difficult to define general characteristics of neuroplasticity mechanisms that are reliably transferable to the individual level. doi:10.1016/j.clinph.2016.10.407
P300 Repetitive magnetic stimulation reverses the synaptic phenotype of cultured rat CA1 pyramidal neurons in a maternal immune activation model of schizophrenia—C. Galanis a,b,c,*, M. Lenz b, V. Aliane c, K. Funke c, A. Vlachos a,b (a Goethe-University, Institute of Clinical Neuroanatomy, Neuroscience Center, Frankfurt/Main, Germany, b Heinrich-Heine-University, Institute of Anatomy II, Faculty of Medicine, Düsseldorf, Germany, c Ruhr-University, Department of Neurophysiology, Medical Faculty, Bochum, Germany) ⇑
Corresponding author.
Question: Gestational infection is a risk factor for psychiatric disorders. Accordingly, preclinical models of maternal immune
Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
Figure 2.
TRSP plots of the TMS-induced oscillatory activity over DLPFC before (left panels) and after (right panels) FP-PAS (upper panels) and PF-PAS (lower panels). A PAS-dependent modulation of oscillatory activity is appreciable, specifically FP-PAS produced an increase of TRSP values whether PF-PAS resulted in the opposite effect. doi:10.1016/j.clinph.2016.10.404
P297 Sensory plasticity changes induced by somatosensory and cerebellar tDCS in alert mice—J. Márquez-Ruiz a,*, C.A. Sánchez-León a, J. Ausín-Azofra b, C. Ammann c, A. Gruart a, J. Delgado-García a (a University Pablo de Olavide, Division of Neurosciences, Seville, Spain, b Laboratorio Europeo de Neurotecnologías Inmersivas, Instituto Labhuman, Valencia, Spain, c Johns Hopkins Medical Institution, Department of Physical Medicine and Rehbilitation, Baltimore, Spain) ⇑
Corresponding author.
Introduction: During the past years, new evidence has revealed the importance of the cerebellar-brain-inhibition (CBI) pathway on cognitive and sensory processing. The modulation of the cerebellar cortex through non-invasive stimulation techniques, as transcranial direct-current stimulation (tDCS), could contribute to the better understanding of neuronal mechanisms underlying the implication of cerebellar cortex in these processes. Objectives: The aim of this study was to explore cerebro-cerebellar interactions affecting long-term plasticity in the somatosensory (SS) cortex by modulating cerebral and cerebellar cortical excitability in behaving mice. Materials and methods: Mice were prepared for the chronic recording of local field potentials (LFPs) in the SS cortex in response to electrical whisker pad stimulation, as well as for simultaneous tDCS. Animals received tDCS over the cerebellum or the SS cortex at different current intensities with a duration of 5 s to asses immediate effects, and during 20 min to address after-effects on SS-LFPs. tDCS effects on long-term plasticity processes in the SS cortex were determined by using two conditioning protocols consisting of 8 and 50 Hz whisker stimulation with a duration of 10 min and 96 s, respectively. Each protocol was combined with the simultaneous presentation of tDCS or sham condition. Results: Anodal increased and cathodal decreased in an immediate way the amplitude of SS-LFPs when applied to the ipsilateral SS cortex, whereas the opposite effects were obtained when tDCS was
presented to the contralateral cerebellar cortex. Concerning longterm after-effects, cathodal tDCS over the SS cortex induced a long-term depression of LFPs whereas no effects were observed after anodal currents. Long-term potentiation of SS-LFPs was evoked by both cathodal and anodal cerebellar tDCS. Finally and as expected, long-term depression and long-term potentiation of SS-LFPs induced by 8 and 50 Hz whisker stimulation were modulated by simultaneous cerebellar tDCS. Conclusions: The results demonstrate the capability of tDCS to modulate the excitability of SS and cerebellar cortices, as well as the potential role of the cerebellar cortex in the control of plastic changes occurring in the sensory cortex of behaving animals. doi:10.1016/j.clinph.2016.10.405
P298 Effects of cerebellar transcranial direct-current stimulation on cerebellar sensory-induced LFPs and Purkinje cell activity in alert mice—C.A. Sánchez-León a, M. Gómez-Climent a, A. Jiménez-Díaz a, J. Delgado-García a, G. Cheron b,c, J. Márquez-Ruiz a,* (a University Pablo de Olavide, Division of Neurosciences, Seville, Spain, b Université de Mons, Laboratory of Electrophysiology, Mons, Belgium, c Université Libre de Bruxelles, Laboratory of Neurophysiology and Movement Biomechanics, Brussels, Belgium) ⇑
Corresponding author.
Introduction: During last years the putative effects of cerebellar transcranial direct-current stimulation (tDCS) has attracted the attention of basic and clinical neuroscientist. Nevertheless, the impact of exogenous electric fields on the different components of the cerebellar network is not already elucidated. Objectives: The aim of this study was to characterize physiological mechanisms underlying short- and long-term effects associated to cerebellar tDCS in alert behaving mice. In particular, we explored the tDCS impact on the cerebellar response to sensory inputs (whisker stimulation) and the potential modulation of Purkinje Cell (PC) discharge rates.
Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
e157
Figure 1.
Materials & methods: Mice were prepared for chronic recording of local field potentials (LFPs) and PC firing in the CrusI/II region of the cerebellum. Along the experimental sessions spontaneous and stimulus-induced (by electrical whisker pad stimulation) activity of PCs (identified by the presence of simple and complex spikes) were recorded before, during and after anodal and cathodal tDCS applied over the cerebellum. For that, we used ring-electrodes placed over the skull allowing simultaneous tDCS stimulation and glass micropipette insertion for LFPs and extracellular unitary recording. tDCS was performed at different current intensities for 5 s to test the immediate effects on sensory-related LFPs and PC activity, and during 20 min to show after-effects on sensory related LFPs. Results: Regarding to the immediate short-term effects (5 s), anodal and cathodal cerebellar tDCS increased and decreased, respectively, the amplitude of N3 component of LFPs induced by simultaneous whisker stimulation. This component has been previously reported to reflect the synaptic activity between parallel fiber and the dendritic tree of PC. Interestingly, longer stimulation sessions (20 min) induced long-term effects that last for more than one hour. Coherently, the firing rate of identified PC was increased or decreased depending of the anodal or cathodal tDCS, respectively. PC response to whisker tactile stimulation was also modulated in the same manner. Conclusions: Present results demonstrate tDCS’s capability for short- and long-term modulation of the cerebellar cortex, and specifically PCs firing activities.
Figure 2.
doi:10.1016/j.clinph.2016.10.406
P299 Inter-individual variability and intra-individual reliability of iTBS-induced neuroplasticity mechanisms in the healthy brain— L. Schilberg *, T. Schuhmann, A.T. Sack (Maastricht University, Cognitive Neuroscience, Maastricht, Netherlands) ⇑
Corresponding author.
Introduction: Neuroplasticity refers to either cortical reorganization or changes in synaptic efficacy between neurons. We combined patterned TMS (iTBS) with electromyography (EMG) to assess and characterize inter-individual variability and intra-individual reliability of TMS-induced neuroplasticity mechanisms in the healthy brain. In the future, reliable measures of TMS-induced neuroplasticity mechanisms could serve as early biomarkers of aberrant cortical neuroplasticity and they could help to guide therapeutic progress of affected individuals. Objectives: To investigate both (1) inter-individual variability and (2) intra-individual reliability of iTBS-induced changes in corticospinal excitability, and (3) the association of individual prolonged measures of corticospinal excitability with iTBS-induced changes in motor evoked potential (MEP) amplitudes. Patients & methods: We applied iTBS over the primary motor cortex (M1) to induce LTP-like mechanisms in fourteen participants on two separate visits and we used EMG from the first dorsal interosseous (FDI) muscle to measure changes in TMS-elicited MEP amplitudes over sixty minutes. We applied sham-iTBS to measure unmodulated prolonged corticospinal excitability. Results: Over a grand period of sixty minutes iTBS led to a group increase of corticospinal excitability, whereas sham-iTBS had no modulatory effects. This increase was reduced on a second measurement (Fig. 1) and individual measures had low reliability (Fig. 2). Furthermore, individual measures of corticospinal excitability over a prolonged time period (sham-visit) of up to sixty minutes were
not associated with the measures of iTBS-induced changes in MEP amplitude of both stimulation visits. Conclusion: At the group level iTBS over M1 has a facilitatory effect on corticospinal excitability. However, this group effect appears to weaken during a second assessment. Furthermore, we find that there is high inter-individual variability and low intra-individual reliability of the observed iTBS-induced neuroplasticity measures. This creates great challenges for the interpretation of group iTBS effects on corticospinal excitability and it is thus difficult to define general characteristics of neuroplasticity mechanisms that are reliably transferable to the individual level. doi:10.1016/j.clinph.2016.10.407
P300 Repetitive magnetic stimulation reverses the synaptic phenotype of cultured rat CA1 pyramidal neurons in a maternal immune activation model of schizophrenia—C. Galanis a,b,c,*, M. Lenz b, V. Aliane c, K. Funke c, A. Vlachos a,b (a Goethe-University, Institute of Clinical Neuroanatomy, Neuroscience Center, Frankfurt/Main, Germany, b Heinrich-Heine-University, Institute of Anatomy II, Faculty of Medicine, Düsseldorf, Germany, c Ruhr-University, Department of Neurophysiology, Medical Faculty, Bochum, Germany) ⇑
Corresponding author.
Question: Gestational infection is a risk factor for psychiatric disorders. Accordingly, preclinical models of maternal immune