John G. Hildebrand

Regents Professor, Neuroscience

I was born in Boston, Massachusetts, in 1942 and grew up in Belmont, MA, where I had all of my precollege education in the town's public schools. By the time I graduated from high school in 1960 and entered Harvard College in Cambridge, MA, I had developed my two life passions: biology and classical music. Although I expected to major in music, I eventually settled on a major in biology, I had the good fortune to work with John Law, then a young faculty member associated with Konrad Bloch's research group in the Chemistry Department. Law not only gave me an unlimited opportunity to immerse myself in laboratory research, but also generously encouraged and aided my scientific development and guided me through the authorship of my first publication and my first presentation at a scientific meeting. Upon receiving the A.B. degree in 1964, I began graduate studies at the Rockefeller Institute (later to become the Rockefeller University) in New York City. After invaluable experiences in the laboratories of George Palade and Christian de Duve, I found my way to the research group headed by Fritz Lipmann. With Lipmann and his long-time colleague Leonard Spector as mentors, I completed a dissertation in the realm of bio-organic chemistry, energy metabolism,and mechanisms of enzymatic reactions. In retrospect one of the most important experiences of my life was a chance encounter in 1965, at the new-book shelf in the Rockefeller library, with a little book by Kenneth Roeder, Nerve Cells and Insect Behavior. Once I started to read that book, I couldn't put it down, and when I had finished it several hours later, I knew what I wanted to do as a scientist.

By the time I received the Ph.D. degree in 1969, I had decided to join the Department of Neurobiology at Harvard Medical School for postdoctoral research training. Fortunate to work with Ed Kravitz and strongly influenced by Steve Kuffler, Ed Furshpan, David Hubel, David Potter, and Torsten Wiesel, as well as a cadre of extraordinary fellow postdocs and graduate students, my three years as a postdoc were exhilarating and profoundly stimulating. In 1972, I accepted an appointment as an Assistant Professor in the same department, established my independent lab, and launched a program of research on the metamorphosis of the nervous system of the giant sphinx moth Manduca sexta. I was promoted to Associate Professor in 1977. In 1980 I moved to the Department of Biological Sciences at Columbia University in New York City, attracted by an invitation to help build a section devoted to developmental neurobiology.

Shortly after my move to Columbia, a casual encounter during a seminar trip introduced me to Gail Burd, a postdoctoral neuroscientist who quickly became a very special friend and colleague and, before long, my wife and life companion. About the same time, another unforeseen opportunity developed when I was invited by the University of Arizona (UA) to consider a challenging assignment in Tucson -- namely, to develop a research group in invertebrate neurobiology. That call proved irresistible, and in 1985 Gail and I headed westward together with four members of my New York lab group. The Arizona Research Laboratories Division of Neurobiology (ARLDN) was inaugurated in December, 1985. At the UA, my primary appointment (which since 1989 has been a Regents Professorship) is in Neurobiology, and I hold joint appointments in Biochemistry & Molecular Biophysics, Entomology, and Molecular & Cellular Biology. Since 1985 I have also served as Director of the ARLDN, and in the period 1986-97 I was Chairman of the Committee on Neuroscience, the UA-wide consortium of faculty members responsible for the UA's Graduate Interdisciplinary Program in Neuroscience.


My group conducts research that combines anatomical, behavioral, chemical, and neurophysiological methods in a multidisciplinary approach to problems of the organization, physiology, functions, and postembryonic development of the insect nervous system. The main goal of this work is to discover fundamental principles and mechanisms common to many or all nervous systems through studies of the experimentally favorable nervous systems of insects. In view of the importance of insects in their own right, we also aim to contribute to knowledge that will help to alleviate the harm done by insects that are predators of the human food supply or vectors of diseases. Areas of our principal interest currently include: the physiology, functional organization, and postembryonic development of the olfactory system; sensory control of mating behavior and insect-host interactions, including feeding and oviposition behaviors; chemical ecology and behavioral aspects of moth-hostplant interactions; olfactory learning and the roles of biogenic amines in plasticity of olfactory function; and functional organization of neurosecretory systems.

Functional organization and physiology of the insect olfactory system. We study the olfactory system of the giant sphinx moth Manduca sexta . Using intracellular recording and staining methods, extracellular and multi-unit recording techniques, and pharmacological manipulations, we explore the neuronal circuitry and synaptic interactions in the antennal lobe (AL), the primary olfactory center in the moth's brain. We also use histological and neuronal tracing methods to learn about the anatomical organization of the AL and its sensory inputs. Our goal is to understand cellular mechanisms of information processing in the olfactory pathways in the CNS. Much of our work has focused on the sexually dimorphic olfactory subsystem in the male moth that is specialized to detect and process information about the female's sex pheromone. We also conduct multi-level studies of the detection and central processing of information about volatile compounds emitted by living plants. In addition to our primary focus on the AL, we are very interested in the higher-order olfactory pathways in the protocerebrum that are involved in processing of the outputs of the ALs and their integration with information of other modalities.

Behavior and chemical ecology. In parallel with our studies of the olfactory system of Manduca, we are investigating the chemical composition of the volatiles emitted by living host- and nonhost plants and using a variety of chemical, physiological and behavioral methods to identify behaviorally significant compounds in those complex mixtures. In addition, we conduct detailed studies of the effects of odors on the behavior of flying Manduca in the field and in laboratory wind tunnels.

Postembryonic, metamorphic development of the olfactory system. We have long been interested in neural development and plasticity in the ALs during the postembryonic development of Manduca . We have shown that certain, sexually dimorphic glomeruli characteristic of male and female ALs develop only if the AL is innervated, respectively, by axons of genetically male or female olfactory receptor cells. In a continuing collaboration among members of my group and faculty colleagues Leslie Tolbert, Lynne Oland, Alan Nighorn and their coworkers, a multidisciplinary quest for the cellular and molecular mechanisms underlying these and other aspects of AL development is in progress.

Organization and functions of neurosecretory systems. We have a long-standing interest in the identification, metabolism, and cellular localization of neuroeffectors (e.g. neurotransmitters, neuromodulators, neurohormones) in insects. Our current efforts focus on the functional organization of neurosecretory cells in the CNS that express neuropeptides and polypeptide neurohormones and on the roles of such cells in the control of organ function and behavior of the insect.