Renshaw said, "Let me list the laser applications for you, if you don't mind my lighting a candle in the sunshine. The laser is coherent radiation, with all the light-waves of the same length and moving in the same direction, so it's noise-free and can be used in holography. By modulating the wave-forms we can imprint information on it with a high degree of accuracy. What's more, since the light-waves are only a millionth the length of radio waves, a laser beam can carry a million times the information an equivalent radio beam can."
Berkowitz seemed amused. " Are you working on a laser-based communication system, Jenny?"
"Not at all," she replied. "I leave such obvious advances to physicists and engineers.-Lasers can also concentrate quantities of energy into a microscopic area and deliver that energy in quantity. On a large scale you can implode hydrogen and perhaps begin a controlled fusion reaction-"
"I know you don't have that," said Orsino, his bald head glistening in the overhead fluorescents.
"I don't. I haven't tried.-On a smaller scale, you can drill holes in the most refractory materials, weld selected bits, heat-treat them, gouge and scribe them. You can remove or fuse tiny portions in restricted areas with heat delivered so rapidly that surrounding areas have no time to warm up before the treatment is over. You can work on the retina of the eye, the dentine of the teeth and so on.-And of course the laser is an amplifier capable of magnifying weak signals with great accuracy."
" And why do you tell us all this?" said Berkowitz.
"To point out how these properties can be made to fit my own field, which, you know, is neurophysiology."
She made a brushing motion with her hand at her brown hair, as though she were suddenly nervous. "For decades," she said, "We've been able to measure the tiny, shifting electric potentials of the brain and record them as electroencephalograms, or EEGs. We've got alpha waves, beta waves, delta waves, theta waves; different variations at different times, depending on whether eyes are open or closed, whether the subject is awake, meditating or asleep. But we've gotten very little information out of it all.
"The trouble is that we're getting the signals of ten billion neurons in shifting combinations. It's like listening to the noise of all the human beings on Earth-one, two and a half Earths-from a great distance and trying to make out individual conversations. It can't be done. We could detect some gross, overall change-a world war and the rise in the volume of noise-but nothing finer. In the same way, we can tell some gross malfunction of the brain-epilepsy-but nothing finer.
"Suppose now, the brain might be scanned by a tiny laser beam, cell by cell, and so rapidly that at no time does a single cell receive enough energy to raise its temperature significantly. The tiny potentials of each cell can, in feed-back, affect the laser beam, and the modulations can be amplified and recorded. You will then get a new kind of measurement, a laser-encephalogram, or LEG, if you wish, which will contain millions of times as much information as ordinary EEGs."
Berkowitz said, "A nice thought.-But just a thought."
"More than a thought, Jim. I've been working on it for five years, spare time at first. Lately, it's been full time, which is what annoys the front-office, because I haven't been sending in reports."
"Why not?"
"Because it got to the point where it sounded too mad; where I had to know where I was, and where I had to be sure of getting backing first."
She pulled a screen aside and revealed a cage that contained a pair of mournful-eyed marmosets.
Berkowitz and Orsino looked at each other. Berkowitz touched his nose. "I thought I smelled something."
"What are you doing with those?" asked Orsino. Berkowitz said, " At a guess, she's been scanning the marmoset brain. Have you, Jenny?"
"I started considerably lower in the animal scale." She opened the cage and took out one of the marmosets, which looked at her with a miniature sad-old-man-with-sideburns expression.
She clucked to it, stroked it and gently strapped it into a small harness.
Orsino said, "What are you doing?"
"I can't have it moving around if I'm going to make it part of a circuit, and I can't anesthetize it without vitiating the experiment. There are several electrodes implanted in the marmoset's brain and I'm going to connect them with my LEG system. The laser I'm using is here. I'm sure you recognize the model and I won't bother giving you its specifications."
"Thanks," said Berkowitz, "but you might tell us what we're going to see."
"It would be just as easy to show you. Just watch the screen." She connected the leads to the electrodes with a quiet and sure efficiency, then turned a knob that dimmed the overhead lights in the room. On the screen there appeared a jagged complex of peaks and valleys in a fine, bright line that was wrinkled into secondary and tertiary peaks and valleys. Slowly, these shifted in a series of minor changes, with occasional flashes of sudden major differences. It was as though the irregular line had a life of its own.
"This," said Renshaw, "is essentially the EEG information, but in much greater detail."
"Enough detail," asked Orsino, "to tell you what's going on in individual cells?"
"In theory, yes. Practically, no. Not yet. But we can separate this overall LEG into component grams. Watch!"
She punched the computer keyboard, and the line changed, and changed again. Now it was a small, nearly regular wave that shifted forward and backward in what was almost a heartbeat; now it was jagged and sharp; now intermittent; now nearly featureless-all in quick switches of geometric surrealism.