Spatially organized flicker can evoke high-frequency responses above
100Hz in visual cortex
Abstract
Flickering visual stimulation targeting the entire visual field can
evoke steady-state visual evoked potentials (SSVEPs), and these SSVEPs
can potentially influence ongoing brain activity. Here, we aimed at
extending previous findings to evoke high-frequency SSVEPs. We
hypothesized that the sequential targeting of neighboring retinal areas
allows evoking a high-frequency series of visual evoked potentials which
sum to a high-frequency SSVEP across the visual cortex. By selectively
and sequentially targeting neighboring retinal areas with high-frequency
flickering light, each area was only stimulated every 10ms, but
neighboring areas were stimulated at a lag of 8.33ms, 6.06ms, 5.55ms,
and 5.26ms (i.e., 120, 165, 180 and 190Hz), for 60 trials of 2s, while
we recorded 64-channel EEG from 10 participants. In line with our
hypothesis, we measured SSVEPs for 120Hz and 180Hz stimulation with an
occipital topography. For the first time, we show that it is possible to
evoke high-frequency SSVEPs as high as 180Hz across the visual cortex by
using a spatially organized noninvasive visual brain stimulation. This
critically extends previous findings on SSVEPs following full-field
visual stimulation. Spatially organized noninvasive visual stimulation
could potentially be used as a tool to influence high-frequency
oscillations, which opens the possibility of targeted therapeutic
interventions.