Breakthroughs, and new crises, in the lab

Lynch Lab sits between a toll road and the UC Irvine main campus, in an office park of indistinguishable low-rise, beige-on-beige stucco buildings. Neuroscientist Gary Lynch had moved his lab and office -- for a while, just a desk in a hallway -- numerous times during his Irvine career, often as the result of some feud or slight. He ended up in the office park largely because everybody -- including him -- concluded all parties would be better-served if there were physical distance between Lynch and his university peers.

The lab is at 101 Theory Drive, a developer's idea of a scientific street name that Lynch found presumptuous.

It is a mark of the difficulty of life sciences -- biology and its many descendants -- that to call something a theory is to honor, not slight it. Theory, evolutionary biologist P.Z. Myers has written, is what scientists aspire to. Lynch, for all of his bombast, was respectful of the intellectual protocols of his science.

"I would have called it Hypothesis Drive," he said.

The hypothesis is the fundamental organizing principle in scientific research. Its "if this, then that" structure underlies almost all scientific experiments. The work in Lynch's lab has been driven by a single overriding hypothesis Lynch first published in 1980.

Lynch proposed that the fundamental act by which a memory was encoded involved a nearly instantaneous physical restructuring of portions of brain cells, called neurons. That restructuring allowed neurons to be built into small networks. Each small network would be a memory, he thought.

Lynch's research focused on a particular area of the brain, a structure called the hippocampus, long thought to be involved in memory. Most neurons in the hippocampus have roughly triangular bodies. Slender fiber extensions called dendrites sprout from the top and bottom. The branches coming out of the top are called apical dendrites. Those coming from the bottom are called basal dendrites.

Also coming out of the bottom is a single larger extension called an axon. All along their lengths, the dendrites are marked by microscopic nubs called spines, thousands of them per dendrite. The axons of one neuron extend to meet the dendritic spines of other neurons. These dendrite-axon junctions are the synapses.

Lynch proposed that the dendritic spines at these junctions changed shape during a process known as long-term potentiation (LTP), which resulted in the strengthening of the bond between a dendrite and an axon. The remodeled dendrites, he said, were the base elements of memory.