Effects of random noise stimulation (tRNS) on the cortical excitability

Introduction: Transcranial application of weak random noise may appear to be a promising tool for clinical neuroplasticity research, for it allows a painless, selective, focal, non-invasive and reversible excitability modulation of the cortex without an adaptation effect. The „random noise“ signal contains all frequencies up to half of the sampling rate, i.e. a maximum of 640Hz. This random level of current generated for every sample (sampling rate 1280 sps) and is normally distributed; the probability density function follows a bell-shaped curve. Methods: Stimulation was delivered by a battery-driven electrical…