Neuroplastic effects of transcranial near-infrared stimulation of different stimulation duration on the cortical excitability

Transcranial Near-infrared-Stimulation as a kind of non-invasive Photobiostimulation of the cortex is able to modulate neurobiological functions without causing thermal damage. The aim of this experiment was to study the impact of different stimulation durations on the cortical excitability. A former study has shown a reduction of cortical excitability after 10 minutes of transcranial near-infrared-stimulation. Therefore we had 14 healthy subject who underwent cortical near-infrared stimulation at a wavelength of 810nm in three different sessions. The duration of the stimulation varied in every session from 5 minutes to 20 minutes and one sham stimulation. The after effects on the cortex were measured using transcranial magnetic stimulation. We found that whereas a 5 Minute stimulation is able to reduce cortical excitability, 20 minutes of Stimulation are enhancing cortical excitability.2018-03-2