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Transcranial electrical stimulation - tDCS and friends

Transcranial electrical stimulation - tDCS and friends. MA Nitsche Georg-August-University, Dept. Clinical Neurophysiology, Goettingen, Germany. Electrical Stimulation in the 18th century. Electrical Stimulation in the 19th century. ( 1910 ). Transcranial electrical stimulation (TES) 1980.

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Transcranial electrical stimulation - tDCS and friends

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  1. Transcranial electrical stimulation - tDCS and friends MA Nitsche Georg-August-University, Dept. Clinical Neurophysiology, Goettingen, Germany

  2. Electrical Stimulation in the 18th century

  3. Electrical Stimulation in the 19th century

  4. (1910)

  5. Transcranial electrical stimulation (TES) 1980

  6. Common aspects of thesetreatments • Suprathreshold stimulation • Phenomenological effects DCS • Subthreshold stimulation • Physiological effects

  7. Principal action of DC-stimulation: modulation of resting membrane potential

  8. Cortical DC-stimulation of the rat: effects during stimulation … Baseline Text Text Text Text cathodal anodal Bindman et al. 1964

  9. …and after-effects anodal cathodal Bindman et al. 1964

  10. After-effects are protein synthesis-dependent Gartside 1968

  11. …and accompanied by specific biochemical alterations 30 min 3 h stimulation dark neurones

  12. 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)

  13. tDCS in humans

  14. Polarity-dependent excitability-modulation during tDCS Nitsche & Paulus 2000

  15. Enhanced motor cortico-spinal excitability after anodal stimulation Nitsche & Paulus 2001

  16. Reduced motor cortico-spinal excitability after cathodaltDCS 1.2 1.0 0.8 0.6 0.4 1 5 10 15 20 25 30 35 40 45 50 55 60 90 120 min Nitsche et al. 2003

  17. DC electrode Intracortical afferents Pt-neuron Mechanisms of action - the electrophysiological perspective

  18. 70 60 Intra-tDCS 50 40 30 DC electrode 20 10 0 Intracortical afferents Pt-neuron Cortico-spinal effects I-O curve Resting motor threshold Active motor threshold 1 mA, 35 cm2 non (a) non (c) anodal cathodal Nitsche et al. 2005

  19. DC electrode Intracortical afferents Pt-neuron Pt-neuron effects TMS TES cathodal anodal 1 mA, 35 cm2 1,5 mA, 35 cm2 Nitsche & Paulus 2000, 2001, Nitsche et al. 2003 Ardolino et al. 2005

  20. DC electrode Intracortical afferents Pt-neuron intracortical effects intracortical facilitation/inhibition cathodal anodal 1 mA, 35 cm2 I-wave facilitation cathodal anodal 1 mA, 35 cm2 Nitsche et al. 2005

  21. DC electrode DC electrode Intracortical afferents Intracortical afferents Pt-neuron Pt-neuron Differentiation between intracortical/corticospinal effects Boros et al. 2008

  22. Conclusion I Cortico-spinal effects SP-MEP, I-O curve, (threshold) Intracortical effects SICI, ICF, (I-waves) Pt neurons (TES) ?????

  23. Na, Ca Mechanisms of action - pharmacological perspective Na, Ca NMDA Transmitter Na, Ca GABA Na, Ca DA Na, Ca ACh Mdodulator Na, Ca Serotonine

  24. Acute effects of tDCS are ion channel-dependent Drug and stimulation condition Nitsche et al. 2003, 2004

  25. Pharmacological dependance of after-effects of tDCS I Nitsche et al. 2003

  26. Pharmacological dependance of after-effects of tDCS II Nitsche et al. 2003, 2004

  27. Pharmacological modulation of after-effects I Nitsche et al. 2006, Kuo et al. 2008

  28. Pharmacological modulation of after-effects II Kuo et al. 2008, 2007, Nitsche et al., 2009

  29. Conclusion II Na, Ca Ca NMDA Ca GLU AMPA AMPA GABA DA ACh Serotonine ???????

  30. Focality of tDCS Imaging Functional M1 premotor Baudewig et al. 2001, Lang et al. 2005 Nitsche et al. 2005

  31. Increasing the focality of tDCS by reducing the size of the stimulation electrode I Nitsche et al. 2007

  32. Increasing the focality of tDCS by reducing the size of the stimulation electrode II

  33. Increasing the focality of tDCS by increasing the size of the reference electrode

  34. Safety of tDCS • No enhancement of NSE (Nitsche & Paulus 2001, Nitsche et al. 2003 • No cerebral edemas or related alterations (Nitsche et al. 2004) • No epileptic seizures (Liebetanz et al. 2006) • Current protocols well below the threshold of tissue damage (Liebetanz et al. 2009)

  35. Recent developments tACS tRNS

  36. tACS Relatively small effects on motor cortex excitability... Antal et al. 2008

  37. ...but prominent functional effects Antal et al. 2008, Kanai et al. 2008

  38. tRNS Motor cortex excitability Motor learning Terney et al. 2008

  39. What to choose

  40. Thanks for your attention

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