The Frontal Cortex

Speaking of the senses, it's always fascinating what happens when that sensory spigot is turned off, so that the cortex is suddenly filled with silence. Jad Abumrad, the co-host of Radio Lab (download their new season!), recently spent some time in an anechoic chamber, or a room designed to stifle soundwaves and erase echoes. The brain, it turns out, can't stand the quiet. When confronted with utter silence, it starts to hallucinate:

Deep in the bowels of a nondescript 1950's era government building is Bell Lab's very own anechoic chamber, no longer in use. The nice folks at Bell Labs agreed to open it up for me. It's a frightening room at first glance. The door is a thousand pounds, the walls ten feet thick, and everything - floors, ceilings, all surfaces - is covered in yellow acoustic baffling. Stranger still, the floor is made of a wire mesh grid and suspended ten feet off the ground (to prevent sound reflecting off the floor).

I remember thinking two things as I walked in. One: this place looks like a beehive. Two: I can't believe how much work it takes to keep out sound. Door closes. Lights off.
Consider: Every room, even the very quietest rooms, have a tone (in fact, in the radio business, we call this "room tone").

But this room had NO ROOM TONE. No sound at all.

And it's impossible to describe what true silence does to your ears. The moment the door went thwuck shut, my ear drums started to flutter. As if air was trying to force it's way out my ears in little puffs. Felt a wee bit nauseous. Crackling. Like shadow static. I think my ears were physically searching for sound.

After about five minutes... A brief, very vivid flash of bees buzzing, like a swarm zooming by my head, doppler style, en route to attack another hive. I'm no idiot. I know my mind invented the bees because 'bee-hive' was one of the last thoughts in my head before the lights went out. Regardless, the sound of bees in the dark was disconcerting.

After about twenty minutes, I began to hear a high pitched whine, which persisted. Not a hallucination, I'd later discover. According to the Bell Labbies, this was probably the sound of my circulatory system. I also heard the gentle thud of my heartbeat.