This is the implication of what Buran and Melcher said. For the brain, there cannot be an environment without danger or prey, or void of the sound that flags them. In the absence of objective outside sound, therefore, the brain turns up the gain on its own amplification system until the buzz of our organic capacitors fills the wiring and gives our auditory sensors the input they crave.

George Michelsen Foy, Zero Decibels, loc. 610