Sarkar put down his fork. “So you can see the last neural gasp, so to speak?”
“Exactly. You know how a standard EEG works: each of the brain’s billions of neurons is constantly receiving excitatory synaptic input, inhibitory input, or a combination of the two, right? The result is a constantly fluctuating membrane potential for each neuron. EEGs measure that potential.”
Sarkar nodded.
“But in a standard EEC, the sensor wires are much bigger in diameter than individual neurons. So, rather than measuring the membrane potential of any one neuron, they measure the combined potential for all the neurons in the part of the brain beneath the wire.”
“Right,” said Sarkar.
“Well, that coarseness is the source of the problem. If only one neuron, or a few dozen or even a few hundred are reacting to synaptic input, the voltage will be orders of magnitude below what an EEC can read. Even though the EEC shows a flat line, brain activity — and therefore life — may still be continuing.”
“A crisp problem,” said Sarkar. “Crisp” was his favorite word; he used it to mean anything from well-defined to delicate to appealing to complex. “So you say you’ve found the solution?”
“Yes,” said Peter. “Instead of the small number of wires used by a standard EEG, my superEEG uses over one billion nanotech sensors. Each sensor is as tiny as an individual neuron. The sensors blanket the skull, like a bathing cap. Unlike a standard EEG, which picks up the combined signal of all the neurons in a given area, these sensors are highly directional and pick up only the membrane potential from neurons directly beneath them.” Peter held up a hand. “Of course, a straight line drawn through the brain will intersect thousands of neurons, but by cross-referencing the signals from all the sensors, I can isolate the individual electrical activity of each and every neuron in the entire brain.”
Sarkar ate another fish ball. “I see why you were having signal-to-noise problems.”
“Exactly. But I’ve solved that now. With this equipment, I should be able to detect any electrical activity at all in the brain, even if it’s just one lone neuron firing.”
Sarkar looked impressed. “Have you tried it yet?”
Peter sighed. “On animals, yes. A few large dogs — I haven’t been able to make the scanning equipment small enough to use on a rat or rabbit yet.”
“So does this superEEG actually do what you want? Does it show the exact, crisp moment of actual death — the ultimate cessation of brain electrical activity?”
Peter sighed. “I don’t know. I’ve got gigabytes of recordings of Labrador retriever brain waves now, but I can’t get a permit to put any of them to sleep.” He spread some more mustard on his meat. “The only way to test it properly will be with a dying human being.”
CHAPTER 6
Peter knocked, then quietly entered the private room in the chronic-care facility. A frail woman about ninety years old was sitting up, the bed’s back raised to a forty-five-degree angle. Two IV bags of clear liquid hung on poles beside her bed. A tiny TV was mounted on a swing arm at the bed’s right.
“Hello, Mrs. Fennell,” Peter said softly.
“Hello, young man,” said the woman, her voice thin and hoarse. “Are you a doctor?”
“No — at least, not a medical doctor. I’m an engineer.”
“Where’s your train?”
“Not that kind of engineer. I’m—”
“I was kidding, son.”
“Sorry. Dr. Chong said you had a good attitude.”
She shrugged amiably, the movement of her shoulders taking in the hospital room, the drip bags, and more. “I try.”
Peter looked around. No flowers. No get-well cards. It seemed Mrs. Fennell was all alone in the world. He wondered how she could be so cheerful. “I, ah, have a favor to ask you,” he said. “I need your help with an experiment.”
Her voice was like dry leaves crumbling. “What kind of experiment?”
“It won’t hurt at all. I’d simply like you to wear a special piece of headgear that has a series of tiny electrodes in it.”
Leaves crumbled in a way that might have been a chuckle. Mrs. Fennell indicated the tubes going into her arm. “A couple more connections won’t hurt, I guess. How long do you want me to wear this?”
“Until, ah, until—”
“Until I die, is that it?”
Peter felt his cheeks grow flush. “Yes, ma’am.”
“What are the electrodes for?”
“My company makes biomedical monitoring equipment. We’ve developed a prototype for a new hypersensitive electroencephalogram. Do you know what an EEC is?”
“A brain-wave monitor.” Mrs. Fennell’s face seemed to be immobile; Chong had said she’d suffered a series of small strokes. But her eyes smiled. “You don’t spend as much time in hospitals as I have without picking up something.”
Peter chuckled. “This special brain-wave monitor is a lot more discerning than the standard ones they’ve got here. I’d like to record, well…”
“You’d like to record my death, is that it?”
“I’m sorry. I don’t mean to be insensitive.”
“You’re not. Why do you want to record my death?”
“Well, you see, right now, there’s no one-hundred-percent accurate way of determining when the brain has permanently ceased to function. This new device should be able to indicate the exact moment of death.”
“Why should anyone care about that? I have no relatives.”
“Well, in many cases bodies are kept on life-support simply because we don’t know whether the person is really dead or not. I’m trying to come up with a definition for death that isn’t just legal but is actually — an unequivocal test that can prove whether someone is dead or alive.”
“And how will this help people?” she said. Her tone made it clear that to her this was what mattered most.
“It’ll help with organ transplants,” Peter said.
She cocked her head. “No one would want my organs.”
Peter smiled. “Perhaps not, but someday my equipment may ensure that we don’t accidentally take organs from people who aren’t yet truly dead. It’ll also be useful in emergency rooms and at accident scenes, to make sure attempts to save a patient aren’t halted too soon.”
Mrs. Fennell digested this for a moment, then: “You don’t really need my permission, do you? You could have just had the equipment hooked up. Just say it was for routine tests. Half the time they don’t explain what they’re doing anyway.”
Peter nodded. “I suppose that’s true. But I thought it would be polite to ask.”
Mrs. Fennell’s eyes smiled again. “You’re a very nice young man, Doctor…?”
“Hobson. But, please, call me Peter.”
“Peter.” Her eyes crinkled. “I’ve been here for months, and not one of the doctors has volunteered that I could call them by their first name. They’ve prodded every part of my body, but they still think keeping emotional distance is part of their job.” She paused. “I like you, Peter.”
Peter smiled. “And I like you, Mrs. Fennell.”
She did manage an unequivocal laugh this time. “Call me Peggy.” She paused, and reflection further creased her wrinkled face. “You know, that’s the only time I’ve heard my own first name since I was admitted here. So, Peter, are you really interested in what happens at the moment of death?”
“Yes, Peggy, I am.”
“Then why don’t you have a seat, make yourself comfortable, and I’ll tell you.” She lowered her voice. “You see, I’ve already died once before.”
“I beg your pardon?” She had seemed so lucid…