Outlasting excitability shifts induced by direct current stimulation of the human brain.
tDCS appears to be a promising tool in neuroplasticity research with some perspectives in clinical neurophysiology. It is closely related to modulation of cortical excitability and activity which are key mechanisms for modulating neuroplasticity. Long-term potentiation and long-term depression-like effects have been shown to be involved in learning processes in animal studies so far. Stimulation with weak direct currents is capable of inducing stimulation-polarity-dependent, prolonged, diminutions or elevations of cortical activity and excitability, most probably elicited by a hyper- or depolarisation of resting membrane potentials. Moreover, these modulations are functionally important, since they affect learning processes and epileptic activity. Here excitability changes have been accomplished in the human by non-invasive transcranial direct current stimulation (tDCS). They share some important features with these well-known neuroplastic changes: The duration of the effects depends on stimulation duration and intensity, they are of intracortical origin, and the prolonged effects depend on NMDA-receptor activity. Thus, this technique is a promising method in the field of neuroplastic research in animals and humans and could evolve as a therapeutic tool in some neuro-psychiatric disorders which benefit from modulation of cortical excitability.
Paulus
Walter
W
Department of Clinical Neurophysiology, University of Göttingen, Robert-Koch-Strasse 40, D-37075 Göttingen, Germany. wpaulus@med.uni-goettingen.de
D001921:Brain / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods*; D004566:Electrodes; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006801:Humans; D009433:Neural Inhibition; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D011601:Psychophysics / Q000379:methods; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D013997:Time Factors
D002121:Calcium Channel Blockers; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D002118:Calcium