MECHANISMS OF NON-INVASIVE BRAIN STIMULATION
-
1
University of Goettingen, Germany
Transcranial electric stimulation techniques have been developed as cheap and efficient tools for modifying cortical plasticity. Repetitive transcranial magnetic stimulation (rTMS) allows increasing or decreasing the excitability of corticospinal or cortico-cortical pathways depending on the intensity and frequency of short stimulation pulses in the range of 100 µs. Here magnetic stimulation is the vehicle which allows transferring transcranially short-pulsed electric energy without inducing skin pain. Direct transcranial electric stimulation of the human brain can be used painlessly if less steep voltage gradients are involved. Weak transcranial direct current stimulation (tDCS) with a homogenous DC field fulfills this requirement ideally (Nitsche and Paulus, 2000). TDCS induces plastic aftereffects via membrane polarization: cathodal stimulation hyperpolarizes, while anodal stimulation depolarizes the resting membrane potential, whereby the induced after-effects depend on polarity, duration and intensity of the stimulation. Transcranial alternating current (tACS) (Antal et al, 2008) and random noise stimulation (tRNS) intend to interfere with ongoing cortical oscillations (Terney et al., 2008). Using these techniques, we can induce and modify differently neuroplastic changes with different advantages and disadvantages of tDCS, tACS and tRNS. Plastic aftereffects need a minimal stimulation duration time and may reverse with too long stimulation. Whereas in the normal stimulation duration range of about 10 minutes tDCS allows for excitability increase and decrease, tACS and tRNS induce only excitability increases in particular with higher frequencies between 100 and 600 Hz or in the low kHz range. TACS and tRNS induce less skin sensation than tDCS and accordingly can be blinded better. They are also no longer current flow direction sensitive. These effects are strongly modified by neuropharmacological co-application: L-DOPA leads to a focusing effect in analogy to its otherwise found U-shaped dose dependency. Dopamine agonists may reverse anodal excitatory tDCS into inhibition, SSRI provide the opposite effect. In conclusion transcranial electrical stimulation techniques allow for targeted modulation of cortical plasticity in man.
Keywords:
plasticity,
Brain,
Humans,
tDCS,
TACs,
tRNS
Conference:
Belgian Brain Council 2014
MODULATING THE BRAIN: FACTS, FICTION, FUTURE, Ghent, Belgium, 4 Oct - 4 Oct, 2014.
Presentation Type:
Oral Presentation
Topic:
Basic Neuroscience
Citation:
Paulus
W
(2014). MECHANISMS OF NON-INVASIVE BRAIN STIMULATION.
Conference Abstract:
Belgian Brain Council 2014
MODULATING THE BRAIN: FACTS, FICTION, FUTURE.
doi: 10.3389/conf.fnhum.2014.214.00018
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
29 Jun 2014;
Published Online:
29 Jun 2014.
*
Correspondence:
Prof. Walter Paulus, University of Goettingen, Goettingen, Germany, wpaulus@med.uni-goettingen.de