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tDCS and friends - an update

tDCS and friends - an update. MA Nitsche Georg-August-University, Dept. Clinical Neurophysiology, Goettingen, Germany. Principal action of DC-stimulation: modulation of resting membrane potential. tDCS in humans. Enhanced motor cortico-spinal excitability after anodal stimulation.

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tDCS and friends - an update

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  1. tDCS and friends - an update MA Nitsche Georg-August-University, Dept. Clinical Neurophysiology, Goettingen, Germany

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

  3. tDCS in humans

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

  5. 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

  6. Na, Ca News from mechanisms of action - pharmacological perspective Na, Ca NMDA Transmitter Na, Ca GABA Na, Ca DA Na, Ca ACh Mdodulator Na, Ca Serotonine

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

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

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

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

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

  12. Enhancing focality of tDCS Imaging Functional M1 premotor Baudewig et al. 2001, Lang et al. 2005 Nitsche et al. 2005

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

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

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

  16. Safety of tDCS I • 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)

  17. Safety of tDCS II - titration in rats Liebetanz et al. 2009

  18. Functional effects of tDCS: when to stimulate Sequence of 12 items, repeated 10 times per block

  19. Procedure Sequence Random block Task routine Sequence learning Sequence learning effect

  20. tDCS over M1during learning anodal cathodal non Reaction time vs baseline Nitsche et al. 2003

  21. When to stimulate II Versuchsablauf I Sequence Random block tDCS Routine learning Sequence learning Effect of sequence learning Kuo et al. 2008

  22. When to stimulate III Jakoubkova et al., in preparation

  23. Where to stimulate Vines et al. 2008

  24. Recent developments - the friends tACS tRNS

  25. tACS I Sinusoidal stimulation with 400 µA, frequency 1-45 Hz, electrode size 4x4 cm, stimulation duration 5 min No effects on motor cortex excitability

  26. tACS II Sinusoidal stimulation with 400 µA, frequency 1-45 Hz, electrode size 4x4 cm, stimulation duration 5 min No effects on EEG frequency bands Also no effects of tACS with DC shifts

  27. tACS III Sinusoidal stimulation with 400 µA, frequency 10 Hz, electrode size 4x4 cm ...but improvement of motor learning (SRTT) with 10 Hz tACS

  28. tACS IV - occipital cortex Sinusoidal stimulation with 0.25- 1 mA, frequency between delta and gamma frequency, electrode size 4x4 cm Kanai et al. 2008

  29. tACS IV - conclusion tACS at the tested frequencies seems to elicit no neuroplasticity on its ownit has however a prominent functional effectsupport of function-related oscillations?Current studies explore the effect of higher frequencies on plasticity

  30. tRNS I 0.1-640 Hz 4x4 cm electrode size 1 mA 10 min stimulation Terney et al. 2008

  31. tRNS II Motor cortex excitability No effects on Rec, ICI, CSP, LICI, increased ICF, no effect on EEG Terney et al. 2008

  32. tRNS III Motor learning Terney et al. 2008

  33. tRNS III Comparison with iTBS and tDCS Terney et al. 2008

  34. tRNS IV tRNS elicits neuroplasticity on its owneffects so far very similar to anodal tDCSpharmacological studies currently donepossible application: disruption of abnormal synchronisation?

  35. What to choose??

  36. Thanks for your attention

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