Investigating the Modulation of Spatio-Temporal and Oscillatory Power Dynamics by Perceptible and Non-perceptible Rhythmic Light Stimulation

The Influence of the Modulation Index on Frequency-Modulated Steady-State Visual Evoked Potentials

“…-They are perceived as more comfortable than traditionally used sinusoidal stimuli (Dreyer et al, 2017). -They can be evoked reliably even with an intensity below the individual perceptibility threshold and in covert attention conditions without direct fixation of the flickering light source (Lingelbach et al, 2021a;Lingelbach et al, 2021b). -Their amplitude, their perceived flicker intensity, as well as the user comfort during the stimulation are affected by the modulation depths via the modulation index (current manuscript).…”

“…They can be evoked reliably even with an intensity below the individual perceptibility threshold and in covert attention conditions without direct fixation of the flickering light source ( Lingelbach et al, 2021a ; Lingelbach et al, 2021b ).…”

“…Other FM-SSVEP stimulation parameters have not been investigated in detail, especially the modulation index. Dreyer and Herrmann (2015) used a modulation index of 0.5 whereas more recent studies used a modulation index of 2.0 ( Dreyer et al, 2017 ; Lingelbach et al, 2021b ). The intuitive reasoning behind this increase was that it elevates the signal power in the targeted frequency in the stimulation signal and should therefore equally increase the measured FM-SSVEP power in EEG electrodes over occipital cortex.…”