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

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

Nov 06, 2022 353 likes •815 views

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

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The neurophysiology of tES

Michael A. Nitsche Department Psychology and Neurosciences Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany

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Modulation of cortical activity and excitability

  • f the human brain

rTM S PAS tDC S

Plasticity Oscillations

tAC S tRN S

Activity

TMS

P L E A S E D O N O T C O P Y

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Actually, electrical brain stimulation has a long history...

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Primary action of tE-stimulation: modulation of resting membrane potential

Rahman et al. 2013

AP threshold

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Cortical DC-stimulation of the rat

Bindman et al. 1964

cathodal

anodal

during after

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50% (?) of transcranially applied direct currents reach the brain

  • calculations on realistic head models, validation

in animal experiments (Rush & Driscoll 1968)

  • validation in humans (Dymond et al. 1975)

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tDCS in humans

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Polarity-dependent excitability- modulation during tDCS

Nitsche & Paulus 2000

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Drug and stimulation condition

Nitsche et al. 2003, 2004

Pharmacological determinants of acute tDCS effects

P L E A S E D O N O T C O P Y

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After-effects of tDCS - plasticity

P L E A S E D O N O T C O P Y

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Drivers and modulators of plasticity

Donchin et al. 2010, Goldman-Racic et al. 2000

Glutamate Dopamine

P L E A S E D O N O T C O P Y

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Nitsche et al. 2003

Drivers of after-effects of tDCS – ion channels

P L E A S E D O N O T C O P Y

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Drivers of after-effects of tDCS - glutamate

Nitsche et al. 2003, 2004

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Drivers of after-effects of tDCS - GABA

Nitsche et al. 2004, Stagg et al. 2009

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Conclusion I

  • Primary effects of tDCS depend
  • n

ion channel activity/polarization

  • After-effects of tDCS depend on

glutamate

  • GABA reduction might contribute
  • For tDCS, calcium-dependent

glutamatergic plasticity can be assumed

P L E A S E D O N O T C O P Y

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Physiology of plasticity I - Determinants

LTD LTP No man‘s land 2 Calcium concentration anodal cathodal No man‘s land 1

Lisman 2001, Nitsche & Paulus 2000

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Physiology of plasticity II - Determinants

LTD LTP No man‘s land 2 Calcium concentration anodal cathodal No man‘s land 1

Monte-Silva et al., 2013

P L E A S E D O N O T C O P Y

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Physiology of plasticity III - Determinants

LTD LTP No man‘s land 2 Calcium concentration anodal cathodal No man‘s land 1

Badsikadze et al., 2013

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Physiology of plasticity IV - Modulation by repetition

Monte-Silva et al. 2010, 2013

anodal cathodal

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Conclusion II

  • tDCS is well suited to induce/model non-

focal plasticity in the human brain

  • Non-linear effects, dependent on

stimulation duration, and strength

  • Late-phase plasticity accomplished by

specific protocols

P L E A S E D O N O T C O P Y

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Network effects of tDCS

Lang et al. 2005

anodal cathodal

P L E A S E D O N O T C O P Y

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tDCS-induced functional connectivity alterations in motor-related networks - fMRI

Polania et al. 2011a

P L E A S E D O N O T C O P Y

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tDCS-induced functional connectivity alterations in motor-related networks - fMRI

Polania et al. 2011a

P L E A S E D O N O T C O P Y

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tDCS-induced functional connectivity alterations

  • f motor cortical networks - EEG

Polania et al. 2011c

P L E A S E D O N O T C O P Y

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tDCS-induced functional connectivity alterations

  • f motor cortical networks - EEG

Polania et al. 2011c

P L E A S E D O N O T C O P Y

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Conclusion III

  • Functional MRI, and EEG allow the identification
  • f stimulation-induced alterations of functional

connectivity of interregional cortical networks

  • Remote effects of tDCS depend at least partially
  • n activation of functionally defined networks

P L E A S E D O N O T C O P Y

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Modulation of cortical oscillations by tES

P L E A S E D O N O T C O P Y

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Antal et al. Brain Stimul 2008

Oscillatory stimulation with alternating currents (tACS)

No neuroplastic effects (?)

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...but frequency-dependent functional effects

Antal et al. 2008, Kanai et al. 2008

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Physiology: Modulation of oscillatory activity by transcranial alternating current stimulation (tACS) I

Ali et al. 2013

P L E A S E D O N O T C O P Y

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Physiology: Modulation of oscillatory activity by transcranial alternating current stimulation (tACS) II

Helfrich et al. et al. 2014

P L E A S E D O N O T C O P Y

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Wischnewski et al., Cerebral Cortex, 2019

Physiology: Modulation of oscillatory activity by transcranial alternating current stimulation (tACS) III

P L E A S E D O N O T C O P Y

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Physiology: Modulation of oscillatory activity by transcranial alternating current stimulation (tACS) IV

Wischnewski et al., Cerebral Cortex, 2019

P L E A S E D O N O T C O P Y

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Neuroplastic effects Conclusions

  • Alteration of oscillations via

prolonged tACS

  • Frequency-specificity of effects
  • Enhancement of

synchronization with neighbored areas

  • Relatively regional effects
  • Additional neuroplastic effects
  • Both, oscillatory, and

neuroplastic effects, depend

  • n NMDA receptors

Wischnewski et al., Cerebral Cortex, 2019

P L E A S E D O N O T C O P Y

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More neuroplastic effects induced by tACS

Moliadze et al. 2010, Chaieb et al. 2011

Ripple frequencies Low kHz

P L E A S E D O N O T C O P Y

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Conclusion IV

  • tACS entrains oscillatory cortical activity
  • Like tDCS, it has a modulatory, but not

inducing effect

  • Dependent on stimulation parameters,

also neuroplastic effects are induced

P L E A S E D O N O T C O P Y

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Transcranial random noise (tRNS) stimulation

Terney et al. 2008

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tRNS – physiological effects I

Terney et al. 2008

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tRNS – physiological effects II

Terney et al. 2008

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tRNS – physiological effects III

Ho et al. 2014

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tRNS – physiological effects IV

Moliadze et al. 2014

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Conclusion V

  • tRNS at high frequencies induces

excitatory neuroplasticity, although mixed effects

  • not clear if it induces random oscillations
  • Effects look similar to anodal tDCS

P L E A S E D O N O T C O P Y

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Final Remarks

  • transcranial electrical stimulation induces acute alterations
  • f

cortical excitability and activity

  • Prolonged tDCS induces neuroplastic after-effects
  • tACS entrains cortical oscillations, some stimulation

protocols also induce neuroplasticity

  • tRNS induces plasticity which share similarities with anodal

tDCS

  • Beyond regional effects also network effects are obtained

P L E A S E D O N O T C O P Y

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Many thanks for your attention!

Team

Min-Fang Kuo Asif Jamil Linda Kuo Aguida Foerster Jessica Grundey Giorgi Batsikadze Shane Fresnoza Jan Grosch Leila Farnad Desmond Agboada Mohsen Mosayebi Ensyie Ghasemian Fatemeh Yavari Alireza Shababaie Ali Salehinejad Lorena de Melo Elham Ghanavati Lin Cho Liu Carmelo Vicario Luca Moretti

Cooperations

  • F. Padberg
  • A. Hasan
  • H. Ehrenreich
  • J. Rothwell
  • A. Pascual-Leone
  • F. Fregni
  • E. Pavlova
  • U. Voss
  • E. Nakamura-Palacios

P.-S. Chen J.C. Chen Funding

P L E A S E D O N O T C O P Y

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