Transcranial random noise stimulation

They showed that by using an alternate current along with random amplitude and frequency (between 0.1 and 640 Hz) in healthy subjects, the motor cortex excitability increased (i.e. increased amplitude of motor evoked potentials) for up to 60 minutes after 10 minutes of stimulation.

The robust changes in cortical excitability observed after tRNS could be attributed to the repeated opening of sodium channels and changes in their kinetics of activation and inactivation[2] or to the increased sensitivity of neuronal networks to modulation.

[3] Since tRNS is a repetitive, random, and subthreshold stimulation, it is speculated that tRNS induces direct temporal summation of neural activity because the time constant of a neuron is sufficiently long to permit the summation of two stimuli presented in close succession.

tRNS is, by definition, a stimulation that induces non-finalized random activity in the system (i.e., noise).

The presence of neuronal noise might enhance the sensitivity of the neurons to a given range of weak inputs[4][5] Transcranial electrical stimulation (tES) generally includes the following techniques: tRNS stimulation differs from tDCS in that instead of constant direct current delivery, current levels are randomly generated, with a normal distribution around a specific mean intensity.