Cheok said different tastes are triggered by molecules that cause chemical ionization on the surface of the tongue, sending the brain electrical signals of a specific amplitude and frequency that are possible to reproduce with two electrodes.
Source: tatoeba (11202380)
We may also conclude that as it was the Ionic γένη of the Attic tetrapolis who in the main achieved the Ionization of Athens, so it was a branch of this same stock that settled at Delos […]