Rex Kerr has been looking at the world with the eyes of a scientist for as long as he can remember. He gives a lot of credit to his father and mother, who, though not scientists themselves, taught Kerr to think like one. "Every project we did at home would be set up in such a way that we talked through how things were set up, why they were set up that way, and what we learned from the project," Kerr says.
Kerr grew up in various small cities and towns in Australia, where his parents homeschooled him. By age 12, when his family moved to California, Kerr had already mastered high school–level mathematics and English, thanks to his parents' focus on the basics, so he taught himself computer programming. Yet it was when he had his first "formal" science classes as an undergraduate at the University of California, Berkeley, that Kerr found his calling.
At Berkeley, Kerr majored in math, physics, and molecular and cell biology. He graduated with highest honors in mathematics and physics and received the Regents' and Chancellor's Fellowship during his four years at Berkeley.
After Berkeley, he moved on to graduate studies at the University of California, San Diego (UCSD), where he was a Lucille P. Markey Fellow. As a Ph.D. student in Bill Schafer's lab at UCSD, Kerr focused on developing methods for using calcium imaging to monitor the activity of the neurons of the nematode worm Caenorhabditis elegans.
Powerful genetics, a small, anatomically characterized nervous system, and easily categorized behaviors make C. elegans an attractive model system for investigating the molecular basis of behavior. But methods for monitoring neuronal activity were lacking. Thanks to the work of Kerr and others, it is now possible to record the activity of individual neurons using calcium indicators—a technique that is now used in a number of labs in the C. elegans community. However, simultaneous monitoring of activity in multiple neurons is still difficult, which leaves direct observation of complete neural circuits out of reach.
After earning his Ph.D., Kerr did a postdoctoral fellowship in the lab of HHMI investigator Terrence Sejnowski at the Salk Institute. His research with Sejnowski focused on the modeling program MCell. The original versions of MCell were focused toward the study of receptor-ligand interactions at geometrically realistic model synapses, and have been used by several dozen groups to study a variety of problems in cell signaling. Kerr used his knowledge of biophysics and computer programming to extend MCell to simulate signal transduction pathways and used these new capabilities to study dynamic processes in bacterial cell division. Both existing MCell users and new groups have expressed considerable interest in using the new version of MCell to tackle increasingly complex aspects of cell signaling.
At Janelia Farm, Kerr will return to his roots, focusing on using calcium imaging to model the activity of neurons in C. elegans. He intends to develop technology and experimental approaches that will enable direct observation of neural circuits in C. elegans. In particular, he wants to build an imaging system that can rapidly capture fluorescent signals from the entire brain instead of from only a single neuron. Kerr also sees a need for technology that can isolate worm mutants with interesting behavioral defects, and image neural activity in worms under normal behavioral conditions.
C. elegans' neuroanatomy is different enough from that of other animals that Kerr says it is unlikely that many of its behavioral circuits are homologous to those that control behaviors in other organisms. However, he believes that a thorough understanding of behavioral circuits in C. elegans can provide inspiration and guide experiments in other organisms.
Even if it takes a while for his first collaborative experiments to get off the ground, Kerr is looking forward to the conversations and exchange of ideas with colleagues and visiting scientists at Janelia Farm whose interests overlap with his own. He would like to work collaboratively with Dmitri Chklovskii, who is working on the overall structure and connectivity of the C. elegans brain, as well as Eugene Myers, whose interest in image processing is relevant to Kerr's own interest in imaging the brain of C. elegans. Likewise, he's looking forward to conversations with Karel Svoboda and Eric Betzig about improving fluorescent signals from optical microscopes.
Kerr said Janelia Farm "has the potential to be great—but we don't know how it will turn out." He first learned of Janelia Farm from his two mentors, Bill Schafer and Terry Sejnowski, at virtually the same time. Although intrigued by what he heard, the scientist in him quickly took over and he began to analyze the advantages and drawbacks of pursuing—and hopefully landing—a job at Janelia. "Eventually," he said, "I saw that the advantages substantially outweighed the drawbacks."