By CP Staff
By Olivia LaVecchia
By Chris Parker
By Jesse Marx
By John Baichtal
By Olivia LaVecchia
By Jesse Marx
By Olivia LaVecchia
Phillips uses a special glue and a small air dryer to attach pill-sized, gold-plated electrodes to Steve's skin: two to measure eye movements; three to measure the muscle tone of his chin; another dozen to measure the electrical activity in his breathing muscles--diaphragm, chest, intercostals. A special sensor taped near his nose measures airflow in and out of the lungs. A finger clip keeps track of the amount of oxygen in his blood.
Finally, anywhere from five to 10 electrodes go on Steve's head to give the techs a kind of picture of his brain activity, an EEG. "You had a nightcap tonight?" Phillips grins. "I'll be able to tell."
Forty-five minutes later, every electrode is in place and tested. A maze of brightly colored wires snakes up through Steve's pajama tops and off his head. Phillips gathers them into a thick ponytail and tapes them together. Then he ushers Steve to a bed in what looks like a cross between a budget hotel room and a hospital room.
Steve lies down and Phillips heads back to his observation post in front of a tall polygraph console covered with hundreds of tiny switches and dials, all hooked up to Steve's wires. Next to the console sits a small television screen broadcasting an image of the patient's bed. Each patient in the sleep lab has a similar setup: The console converts all the pulsing energy picked up by the electrodes into clear signals that in turn cause a dozen pens on the polygraph to jump and dip as the paper scrolls past underneath. By morning, Steve will have generated a giant book some 4 inches thick, a printed record of his sleep--every breath, twitch, and dream.
Most of what is known about sleep comes from these charts (the rest comes from experiments on cats) and it's a pretty fuzzy picture. The sensors act like microphones, picking up any electrical noise in the skull. Because they're not attached directly to brain tissue, Phillips explains while he flips a button and inspects the result on the polygraph paper, the sensors record only general brain activity.
"They're on top of the muscle, which is on top of the bone, which is on top of the brain," he says. "And that's a lot of interference." It is possible to implant tiny electrodes inside individual brain cells--but only in animals.
But even through all that tissue, the EEG tells a lot about our brains. It responds to subtle changes in brain chemistry and electrical activity, whatever the cause: street drugs, for example, or medication; insanity or sleep. "An alcoholic has a very faint EEG reading," Phillips says. "And if you've been on Prozac ever in your life, the waves are wild, all over the place."
Phillips picks up a phone near the TV monitor and asks Steve to move his eyes, his legs, take a deep breath. He scribbles in red pen on the printout after each test. Then he shuts off the light and wishes Steve a good night.
Steve rolls over on his back and closes his eyes while Phillips keeps an eye on the printout. It shows that Steve is awake: His eye movement is steady, without wild variations. His brain waves are random, but slowly start to resemble the more regular alpha waves of drowsiness. Whenever Steve shifts position, scratches, or sighs, all the pens sensing muscle activity respond suddenly by tracing out bouncing, heavy spikes. Phillips notes these jolts on the chart: "rolled onto back," or "coughed." As Steve relaxes, so do his readings.
Phillips says most of us mistakenly believe it takes a long time to fall asleep. In fact, it only takes a few minutes for a normal person to descend into the first stages of sleep--even in an unfamiliar place like the sleep lab, and even wired to a maze of electrodes. Steve passes the threshold in just eight minutes, drifting in and out of the first four stages of sleep. His EEGs open up into wider, slower waves. Sleep spindles, short bursts of electricity from the thalamus, show up on his chart. Then the K-complexes appear: wide, regular waves that come more and more frequently, until they take over completely during deeper stage four, or delta sleep.
An hour later, everything suddenly changes. His muscle tone goes flat and his chin sensor shows almost no electrical activity at all. But the polygraph pen is bouncing around at random. His brain appears to be awake. The readouts from his left and right eyes are frenzied, waving up and down, the two lines pinching together and flipping apart as Steve looks to his left and to his right. On the television screen, Steve looks just as he did in slow-wave sleep. If anything, he appears to be even deeper in sleep, utterly motionless. He has entered rapid-eye-movement, or REM sleep, the stage that gives us our most vivid dreams.
It used to be commonly held that sleep was merely the absence of brain activity, that it was essentially the same thing as rest. But the polygraph proves that isn't the case. In fact, our brains are even more active during some phases of sleep than they are when we are awake--so active that our brain stem has to jam the motor signals going to the spinal cord to keep us from getting up and acting out our dreams.