a very nice lady died tonight.”
Cathy looked compassionate. She nodded.
“I’m exhausted,” said Peter. “I’m going back to bed.” He gave her a quick kiss, and did just that.
FOUR HOURS LATER Peter woke up with a headache. He stumbled to the bathroom, where he shaved and showered. He then filled a large tumbler with Diet Coke, got the disk, and went to his study.
His home system was more powerful than the mainframe he’d had to share access to as a student at university. He turned it on, inserted the disk into the drive, and activated the wall monitor on the other side of the room. Peter wanted to see the moment at which the last neuron had fired, the moment at which the last synapse had been made. The moment of death.
He selected a graphic display mode and played a few seconds of the data, having the computer plot every location at which a neuron had fired. Not surprisingly, the image on the screen looked exactly like a silhouette of a human brain. Peter used an edge-tracing tool to draw the outline of Mrs. Fennell’s brain. There was enough data to generate the picture three dimensionally; Peter rotated the image until the brain silhouette was facing him directly, as if he was looking the late Mrs. Fennell straight in the optic nerves.
He let the data play in real time. The computer looked for patterns in the firing neurons. Any connected series that fired once was color-coded red; twice, orange; three times, yellow; and so on through the seven colors of the spectrum. The picture of the brain looked mostly white: the combined effect of all the different colors of tiny dots. Peter occasionally zoomed in to see a close-up of one section of the brain, lit up with strings of infinitesimal Christmas lights.
As he watched, he could clearly see the stroke that had proved the final straw for Peggy Fennell. The color-coding scheme was refreshed every tenth of a second, but soon an area of blackness began to grow in her left temporal lobe, just below the Sylvian fissure. It was followed by an increase in activity, with the whole brain growing brighter and brighter as disinhibition caused neurons to fire again immediately after they’d last fired. After several moments, a complex network of purple lights was visible throughout her brain, a whole series of neural nets being triggered in identical patterns over and over as her brain spasmed. Then the nets began to fade, and no new ones replaced them. After ninety years of service, Peggy Fennell’s brain was giving up the ghost.
Peter had hoped to be able to watch it all dispassionately. It was just data, after all. But it was also Peggy, that brave and cheerful woman who had faced and beaten death once before, that woman who had held his hand as she passed from life into lifelessness.
The data continued to be plotted, and soon there were only a few patterns of light, like constellations on a foggy night, flickering on the screen. When the activity did stop, it did so without any apparent flourish. Not a bang. Not a whimper. Just nothingness.
Except …
What was that?
A tiny flash on the screen.
Peter reversed the recording, then played it back again at a much slower speed.
There was a minuscule pattern of purple lights—a persistent pattern, a pattern that kept firing over and over again.
And it was moving.
Neurons couldn’t really move, of course. They were physical entities. But the recorder was picking up the same pattern over and over again, just slightly displaced to the right each time. The recorder allowed for such displacements: neurons didn’t always fire in exactly the same way, and the brain was gelatinous enough that movements of the head and the pulsing of blood could slightly change the physical coordinates of a neuron. The pattern moving across the screen must have been propagating from neuron to adjacent neuron in steps small enough that the recorder mistook the individual increments for activity within the same neurons. Peter glanced at the scale bar at the bottom of the wall screen. The violet pattern, a complex knot like intestines made of neon tubes, had already shifted five millimeters, far more than any neuron could move within the brain except in the case of a major blow to the head, something Peggy Fennell had most assuredly not suffered.
Peter adjusted a control. The playback speeded up. No doubt about it: the knot of violet pinpricks was moving to the right,