Abstract
Patricia DeCoursey was a pioneer in many ways. She was a research scientist and a professor at a time when few women held such jobs. For many years, she was a single mother (a widow) and was able to raise her family in a beautiful home. In her research, she helped to define a key function, the phase response curve (PRC) to light (DeCoursey, 1960a, 1960b). Her behavioral studies were meticulous and wonderfully detailed. She worked with others to publish what remains our core chronobiology textbook (Dunlap et al., 2004). In her later career, she conducted some of our field’s most impactful “clocks in the wild” studies (DeCoursey, 2014).
Pat’s career as a Professor of Biological Sciences at the University of South Carolina included both laboratory and field studies. She studied flying squirrels and golden hamsters, and in her naturalistic studies, chipmunks, white-tailed antelope squirrels, and golden-mantled ground squirrels. From 2006 to 2019, Pat directed the W. Gordon Belser Arboretum, a 10-acre teaching forest for the university.
Pat’s early life was unusual for several reasons. She was a triplet with an identical twin sister. Her family spent one summer camping in northern wilderness forests. When Pat was in fourth grade, she moved to Washington, DC, but she maintained a love of the wilderness. In high school in New York City, she completed a census of all the songbirds in a forest in Long Island, winning finalist status in the 1950 Westinghouse Science Talent Search. She attended Cornell University for her undergraduate degree in zoology and then received her PhD in zoology and biochemistry at the University of Wisconsin–Madison. She conducted postdoctoral research for 2 years at the Max-Planck Institute in Erling-Andechs, Germany, with Jurgen Aschoff. She even served as one of the early subjects of a “bunker” experiment, living in temporal isolation for 28 days. Her enthusiasm for science is nicely reflected in the text of a letter she wrote to her sister Cynthia at the time:
May 27, 1961
“Then started an even more unusual part of the trip! Dr. Aschoff is the leading worker here in Europe on activity rhythms, and it is not too surprising that he would get interested in measuring endogenous rhythms in humans. Because of the many difficulties there were simply no good experiments before a month ago. Dr. Aschoff has been adapting an old war Bunker—deep underground in the Cherugie Klinik in Munich—and as I arrived in Erling on the way to Vienna—he had just returned from a week’s sojourn as 1st experimental animal. I am the 2nd! The Bunker is really a very comfortable and likeable room now -but the passageways one torturously wanders along to get to it underground remind me of some medieval dungeon. Here I have been comfortably and happily imprisoned for 2 weeks -just imagine 2 weeks without disturbance. Unbelievable! The room is soundproof and all Kontakts are one way—i.e. one could think that no one else in the world were still living—but actually many recording devices continually record my temperature, activity, sleep—work rhythms etc.—and during the day I periodically push buttons on the switchboard that records other rhythms. But here in my comfortable room I am aware neither of the battery of people or recording devices outside. Needless to say, my watch was ceremoniously taken away at the start -and the question is whether I remain rhythmic and what the frequency of such a rhythm is. The feeling of such timelessness here in isolation is hard to describe.! I can only say that one is well aware of when he is tired at night and must go to bed, and also more or less when one should get up -but one doesn’t realize how dependent one is upon a watch or the sun in normal life until he is put in a situation like this.
I’ll tell you more when I am again free in the outer world and have worked on the data. Apart from the peace and quiet—and chance to get my work done—it is esthetically pleasing to be an experimental animal oneself for a change. George says it is poetic justice—after all the flying squirrels that I have kept in isolation and measured their activity rhythms—to see the other side of the picture. I can only say that the accuracy and precision of my squirrels’ time sense will undoubtedly put me to shame.”
Pat met her husband, George, while he was at Cornell. They shared a love of nature, with George majoring in Ornithology. In 1967, they moved to the University of South Carolina. While George received a position as an Associate Professor, Pat was offered a position as a Research Professor. Pat took a leave of absence from her position to raise her 2 children, Cynthia and Mark.
She had left academics to raise a family, but sadly her husband, George, died prematurely of cancer in his 40s, and Pat had to go back to work. At the University of South Carolina, she was friends with F. John and Winona Vernberg who directed the Belle W. Baruch Institute for Marine Biology and Coastal Research at the University. The Vernbergs arranged a faculty position in the Baruch Institute for Pat and she then had to find a project relevant to marine biology. Pat needed a research technician, and through interaction at his undergraduate thesis examination, she connected with Joe Takahashi and Pat offered him the job. After graduation from Swarthmore, he moved to Columbia, South Carolina, to work with Pat in the Baruch Marine Institute. He comments,
The year that I spent with Pat was truly wonderful. She became my mentor and I became her circadian rhythms enthusiast. Although we could not work on circadian rhythms directly, we decided to work on a project to study the daily vertical migration of zooplankton in the water column in the estuary at the Baruch Institute field station. When we were back in Columbia on the main campus, Pat and I had countless discussions on circadian rhythms.
Pat’s first paper was a single author report published in Science on 1 January 1960 entitled “Daily light sensitivity in a rodent,” summarizing her PhD thesis studies (DeCoursey, 1960a). She presented her studies of the light pulse PRC in the 1960 meeting of the Cold Spring Harbor Symposium that brought together the people we consider the founders of our field. The proceedings of this symposium were published as a book, with papers and also discussion transcriptions.
Pat’s paper for the Cold Spring Harbor Symposium, “Phase control of activity in a rodent,” included some beautiful data demonstrating the tight coupling between activity onset measured from one flying squirrel and time of sunset (DeCoursey, 1960b). She demonstrated free-running rhythms of individual flying squirrels housed in constant darkness that showed amazing precision. Noting that some animals showed free-running periods (FRPs) greater than 24 h while others showed FRPs less than 24 h, she examined the pattern of entrainment to LD cycles and saw that the first group entrained with respect to dawn, whereas the others entrained with respect to dusk. She then conducted what were then called “light shock” experiments to measure the light pulse PRC from these animals using the PRC to explain the patterns of entrainment. Although PRCs to light had been studied for years, Pat provided clear demonstrations of how this was used for control of phase of entrainment within a population with varied FRPs. She continued her research to demonstrate how these animals would sample the light levels at the entrance of their burrows, heading back to the nest to sleep a bit more as the light induced a phase delay shift to maintain entrainment.
In the early 1980s, Pat did a 1-year sabbatical with Michael Menaker at the University of Oregon, Eugene (where Joe Takahashi was a graduate student with Menaker). Pat and Joe conducted an amazing set of experiments there on the spectral sensitivity of the circadian clock to light in the hamster, which was published in the journal Nature in 1984 (Takahashi et al., 1984). Joe comments, “Pat was a joy to work with and was such a gentle and warm but motivated person. She was a perfectionist and everything she touched was beautiful.”
In 1986, Mary Harrington visited Pat’s lab as a postdoc to spend several months setting her up to conduct immunocytochemical studies. Pat needed to learn this then-new technique to complete her ongoing SCN transplant studies (DeCoursey and Buggy, 1989). Soon after she completed the transplant work, she focused on the fundamental question of the adaptive value of SCN-driven rhythms. Can an animal survive and reproduce without an SCN? First, studies with SCN lesion or sham-surgery chipmunks were conducted at the Mountain Lake Biological Station in Virginia (DeCoursey and Krulas, 1998). In the studies during the 1997 season, they observed a predator, likely a weasel, killing the SCN-lesion chipmunks. Their studies showed that a chipmunk with SCN lesion moved more while within the burrow compared with the intact control. Does sleeping soundly in this instance offer adaptive value?
After a discouraging experiment with antelope ground squirrels where a feral cat found its way into the desert enclosure and methodically killed nearly half of the study subjects (DeCoursey et al., 1997), the focus shifted to golden-mantled ground squirrels and a wilderness National Forest Research site, free of feral cats. Pat also conducted meticulous laboratory studies to document the impact of SCN lesions on survival of hibernating golden-mantled ground squirrels. Although in the laboratory 100% of SCN-lesion ground squirrels survived a simulated winter season, in the field none survived the winter (DeCoursey, 2014). These studies demonstrate the adaptive value of the SCN for survival and the importance of field research in addressing this question.
Pat served the Society for Research on Biological Rhythms (SRBR) throughout her career. She was on the organizing committee for both the Journal of Biological Rhythms and SRBR. She served 2 terms as SRBR Secretary and also served on the advisory boards of both groups.
Despite her innovative professional forays, some things about Pat never changed, especially her love of nature. She enjoyed hiking, gardening, and community service. She helped design a flower clock for her university’s arboretum, in this project melding her varied interests.
Pat delighted in talking with students. She generously shared stories from her career, but quickly turned the conversation to question young researchers about their own studies. She was adept at asking conceptual questions that offered wise direction for future studies. We will all miss her wisdom, kindness, and generosity.
