Y P O C T The neurophysiology of tES O N O D Michael A. - PowerPoint PPT Presentation

Y P O C T The neurophysiology of tES O N O D Michael A. Nitsche E Department Psychology and Neurosciences S Leibniz Research Centre for Working Environment and Human Factors, Dortmund, A Germany E L P

Y P Modulation of cortical activity and excitability O of the human brain C T Activity Oscillations Plasticity O N TMS rTM PAS tDC tAC S S S O D E S tRN A S E L P

Y P Actually, electrical brain stimulation O has a long history... C T O N O D E S A E L P

Y Primary action of tE-stimulation: P modulation of resting membrane O C potential T O N O D E S A E AP threshold L P Rahman et al. 2013

Y P O Cortical DC-stimulation of the rat C during after T O N cathodal O D E S A anodal E L P Bindman et al. 1964

Y P O 50% (?) of transcranially C T applied direct currents reach O the brain N O D - calculations on realistic head models, validation E in animal S experiments (Rush & Driscoll 1968) A - validation in humans (Dymond et al. 1975) E L P

Y P O tDCS in humans C T O N O D E S A E L P

Y P Polarity-dependent excitability- O C modulation during tDCS T O N O D E S A E L P Nitsche & Paulus 2000

Y P Pharmacological determinants of acute tDCS O effects C T O N O D E S A E L P Drug and stimulation condition Nitsche et al. 2003, 2004

Y P O After-effects of tDCS - plasticity C T O N O D E S A E L P

Y P Drivers and modulators of O plasticity C T Glutamate Dopamine O N O D E S A E L P Donchin et al. 2010, Goldman-Racic et al. 2000

Y P Drivers of after-effects of tDCS – ion channels O C T O N O D E S A E L P Nitsche et al. 2003

Y P Drivers of after-effects of tDCS - glutamate O C T O N O D E S A E L P Nitsche et al. 2003, 2004

Y P Drivers of after-effects of tDCS - GABA O C T O N O D E S A E L P Nitsche et al. 2004, Stagg et al. 2009

Y P O Conclusion I C T -Primary effects of tDCS depend O on N ion channel activity/polarization O - After-effects of tDCS depend on D glutamate E - GABA reduction might contribute S A - For tDCS, calcium-dependent E glutamatergic plasticity can be L assumed P

Y Physiology of plasticity I - P O Determinants C No man ‘ s land 2 T O N Calcium concentration LTP O D No man ‘ s land 1 E S A E LTD L P anodal cathodal Lisman 2001, Nitsche & Paulus 2000

Y Physiology of plasticity II - P O Determinants C No man ‘ s land 2 T O N Calcium concentration LTP O D No man ‘ s land 1 E S A E LTD L P anodal cathodal Monte-Silva et al., 2013

Y Physiology of plasticity III - P O Determinants C No man ‘ s land 2 T O N Calcium concentration LTP O D No man ‘ s land 1 E S A E LTD L P anodal cathodal Badsikadze et al., 2013

Y Physiology of plasticity IV - P O Modulation by repetition C anodal cathodal T O N O D E S A E L P Monte-Silva et al. 2010, 2013

Y P O Conclusion II C T O • tDCS is well suited to induce/model non- N focal plasticity in the human brain O D • Non-linear effects, dependent on E stimulation duration, and strength S A E • Late-phase plasticity accomplished by L specific protocols P

Y P Network effects of tDCS O C anodal cathodal T O N O D E S A E L P Lang et al. 2005

Y P tDCS-induced functional connectivity O alterations in motor-related networks - fMRI C T O N O D E S A E L P Polania et al. 2011a

Y P tDCS-induced functional connectivity O alterations in motor-related networks - fMRI C T O N O D E S A E L P Polania et al. 2011a

Y P tDCS-induced functional connectivity alterations O of motor cortical networks - EEG C T O N O D E S A E L P Polania et al. 2011c

Y P tDCS-induced functional connectivity alterations O of motor cortical networks - EEG C T O N O D E S A E L P Polania et al. 2011c

Y P Conclusion III O C T O • Functional MRI, and EEG allow the identification N of stimulation-induced alterations of functional connectivity of interregional cortical networks O D • Remote effects of tDCS depend at least partially E on activation of functionally defined networks S A E L P

Y P Modulation of cortical oscillations by O tES C T O N O D E S A E L P

Y P Oscillatory stimulation with O alternating currents (tACS) C T O N O D No neuroplastic effects (?) E S A E L P Antal et al. Brain Stimul 2008

Y P ...but frequency-dependent O functional effects C T O N O D E S A E L P Antal et al. 2008, Kanai et al. 2008

Y P Physiology: Modulation of oscillatory activity by O transcranial alternating current stimulation (tACS) I C T O N O D E S A E L P Ali et al. 2013

Y P Physiology: Modulation of oscillatory activity by O transcranial alternating current stimulation (tACS) C II T O N O D E S A E L P Helfrich et al. et al. 2014

Y P Physiology: Modulation of oscillatory activity by O transcranial alternating current stimulation (tACS) C III T O N O D E S A E L P Wischnewski et al., Cerebral Cortex, 2019

Y P Physiology: Modulation of oscillatory activity by O transcranial alternating current stimulation (tACS) C IV T O N O D E S A E L P Wischnewski et al., Cerebral Cortex, 2019

Y P O Neuroplastic effects Conclusions C T - Alteration of oscillations via O prolonged tACS N - Frequency-specificity of effects O - Enhancement of D synchronization with neighbored areas E S - Relatively regional effects A - Additional neuroplastic effects E L - Both, oscillatory, and P neuroplastic effects, depend on NMDA receptors Wischnewski et al., Cerebral Cortex, 2019

Y P More neuroplastic effects induced by tACS O C Ripple frequencies Low kHz T O N O D E S A E L P Moliadze et al. 2010, Chaieb et al. 2011

Y P O Conclusion IV C T O • tACS entrains oscillatory cortical activity N O • Like tDCS, it has a modulatory, but not D inducing effect E S A • Dependent on stimulation parameters, E also neuroplastic effects are induced L P

Y P Transcranial random noise O (tRNS) stimulation C T O N O D E S A E L P Terney et al. 2008

Y P O tRNS – physiological effects I C T O N O D E S A E L P Terney et al. 2008

Y P O tRNS – physiological effects II C T O N O D E S A E L P Terney et al. 2008

Y P O tRNS – physiological effects III C T O N O D E S A E L P Ho et al. 2014

Y P O tRNS – physiological effects IV C T O N O D E S A E L P Moliadze et al. 2014

Y P O Conclusion V C T O • tRNS at high frequencies induces N excitatory neuroplasticity, although mixed effects O D E • not clear if it induces random oscillations S A E • Effects look similar to anodal tDCS L P

Y P Final Remarks O C  transcranial electrical stimulation induces acute alterations of cortical excitability and activity T O N  Prolonged tDCS induces neuroplastic after-effects O D  tACS entrains cortical oscillations, some stimulation E protocols also induce neuroplasticity S A  tRNS induces plasticity which share similarities with anodal E tDCS L P  Beyond regional effects also network effects are obtained

Y P Team Cooperations Funding O Min-Fang Kuo F. Padberg Asif Jamil C A. Hasan Linda Kuo H. Ehrenreich Aguida Foerster T Jessica Grundey J. Rothwell O Giorgi Batsikadze Shane Fresnoza A. Pascual-Leone N Jan Grosch F. Fregni Leila Farnad Desmond Agboada O Mohsen Mosayebi E. Pavlova D Ensyie Ghasemian Fatemeh Yavari U. Voss Alireza Shababaie E Ali Salehinejad E. Nakamura-Palacios Lorena de Melo S Elham Ghanavati A P.-S. Chen Lin Cho Liu Carmelo Vicario E Luca Moretti J.C. Chen L Many thanks for your attention! P

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