40 Hz · gamma light & sound

Flashing light. Light mode flashes the whole screen many times a second. Don't use it if you have epilepsy or have ever had a seizure, and stop if you feel dizzy or unwell. Tap, click, or press any key to stop.

40 Hz sits in the brain's gamma band. MIT researchers call stimulating it with flickering light, pulsing sound, or both GENUS (Gamma ENtrainment Using Sensory stimuli), and have studied it in mice and in early human trials. This page is an experiment, not a treatment.

Display. A screen changes only once per frame, so the light can flash only at the refresh rate divided by a whole number. 40 Hz is exact on 120 Hz and 240 Hz displays. On a 60 Hz display the light falls back to 30 Hz, while the sound stays exact.

Sound. clicks are 1 ms tone pips, one per cycle, as in the MIT studies. am tone is a steady tone whose volume rises and falls each cycle. binaural plays a slightly different tone in each ear, and only works with headphones.

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