The Memory Hacker

Measuring these patterns, and programming the results in terms that a computer chip can understand, is what occupies John Granacki, a specialist in circuitry and part of Berger´s interdisciplinary research team at the ISI in Marina del Ray. In the elevator on the way up to Granacki´s office, Berger boasts, â€These people are really cutting-edge. They´re the ones who invented the Internet.†(Actually, as Granacki later explains to me, they hosted the West Coast sector of Arpanet-the academic proto-Web -in the 1970s, but close enough.)

When we meet Granacki, he´s clad in chinos and a starched button-down shirt. Rectangular, rimless glasses slide down his nose. No sooner do we sit down than he and Berger begin talking shop about chip production schedules and new math models. Suddenly I feel like the only one in the room who´s speaking English.

For the past four years, Granacki has been trying to develop circuitry that could translate Berger´s equations into electrical pulses. The big mechanical hurdle has been figuring out a way to reduce the amount of heat generated by the transistors so that a chip won´t damage healthy brain cells. The solution was to create a more complex version of the same kind of digital circuit that performs computations for a family desktop, except far smaller.

Jeff LaCoss, the senior electrical engineer on Granacki´s team, hands me a working model of the memory chip. Similar to the one I witnessed at Wet Lab 412C and lighter than a feather, it disappears in my palm. The chip, LaCoss tells me, represents 100 neurons that can individually receive analog signals from live brain tissue, convert them to digital signals, and then reconvert them to an analog signal relayed to healthy neurons on the other side. â€We still need to do some tinkering,†cautions LaCoss, stealing a glance at his boss. â€But I´d say it´s just about ready to go.â€

LESS THINKING, MORE DOING

For all their lofty ambitions and recent progress, Berger and his team still don´t understand how the brain processes and sorts information any better than other neuroscientists do-one reason, he admits, why many of them have criticized his work. â€They tell me I don´t know what memory is, which is true,†he says, walking with me toward the parking lot. â€And they ask how I can replace something that I don´t understand.â€

Berger´s answer is simple: Just by doing it. Later this year, Berger´s colleagues at Wake Forest will hook up a more complex version of the chip to live lab rats whose memories have been temporarily disabled by drugs. If the animals´ brains react to the computer-supplied signals with the same regularity as the slice of rat brain in Wet Lab 412C does, it will, Berger says, be a â€monumental†moment. â€We´ll prove we can replace a central part of the brain that has lost a higher cognitive function, such as memory, with a microchip,†he says.