Spatiotemporal resonance in mouse primary visual cortex

SUMMARY Human primary visual cortex (V1) is entrained by the rhythmic light and responds more strongly, or resonates, to ∼10, ∼15-20, ∼40-50 Hz flicker. Full-field flicker also elicits geometric hallucinations, the origin of which has only been explored in computational models and human EEG with limited spatial resolution. Here, we recorded cortical responses to flicker in awake mice using high spatial resolution widefield imaging in combination with high temporal resolution glutamate-sensing fluorescent reporter (iGluSnFR). Resonance frequencies in mouse V1 were similar to those in humans (8 Hz, 15 Hz, 33 Hz). Spatially, all flicker frequencies evoked responses in V1 corresponding to retinotopic stimulus location and some evoked additional spatial peaks. These flicker-induced cortical patterns displayed standing wave characteristics and matched linear wave equation solutions in an area restricted to the visual cortex. Taken together, the interaction of travelling waves with cortical area boundaries leads to spatiotemporal activity patterns, which may affect perception.