All healthy cells have a built - in mechanism for suicide; it's switched on by signals received from their environment. (discovermagazine.com)
When signals received by the eyes don't match those being understood by your inner ear (the center of balance in the human body), motion sickness occurs. (travelinsurancereview.net)
Both act as switches that can either transmit or not transmit electrical pulses, depending on signals they receive. (discovermagazine.com)