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Patricia Jackson DeCoursey (December 28, 1932 – January 1, 2022) was an American biologist. A leading researcher in the field of
chronobiology Chronobiology is a field of biology that examines timing processes, including periodic (cyclic) phenomena in living organisms, such as their adaptation to solar- and lunar-related rhythms. These cycles are known as biological rhythms. Chron ...
, her research focused on behavioral, physiological, and ecological aspects of mammalian
circadian rhythms A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., endogenous) and responds to the environment (is entrai ...
.DeCoursey’s Textbook: Summary & About the Authors
/ref> She is credited with creating the first
Phase Response Curve A phase response curve (PRC) illustrates the transient change (phase response) in the cycle period of an oscillation induced by a perturbation as a function of the phase at which it is received. PRCs are used in various fields; examples of biolog ...
(PRC). PRC’s are used throughout the field today to help illustrate the change of a biological oscillation in response to an external stimulus. She worked as a biology professor at the
University of South Carolina The University of South Carolina (USC, SC, or Carolina) is a Public university, public research university in Columbia, South Carolina, United States. Founded in 1801 as South Carolina College, It is the flagship of the University of South Car ...
(USC) from 1967 until her retirement as director of the W. Gordon Belser Arboretum in 2019.


Biography

At an early age, DeCoursey expressed much interest in nature. She became fascinated with the outdoors though traveling with her father, a physician, and the rest of her family to remote wilderness areas While attending Hunter College High School in New York City she began collecting data on the
songbirds A songbird is a bird belonging to the suborder Passeri of the perching birds (Passerine, Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin ''oscen'', "songbird". The Passeriformes co ...
of a hardwood forest in
Long Island Long Island is a densely populated continental island in southeastern New York (state), New York state, extending into the Atlantic Ocean. It constitutes a significant share of the New York metropolitan area in both population and land are ...
. She mapped the number and location of the birds as well as their distinctive calls. She entered this project in the 1950
Westinghouse Science Talent Search Westinghouse may refer to: Businesses Current companies *Westinghouse Electric Corporation, the company that manages the Westinghouse brand, with licensees: **Westinghouse Electric Company, providing nuclear power-related services ** Westingho ...
and was named a finalist along with her twin sister Cynthia (Jackson) Fisher.


Education

DeCoursey's interest in ornithology led her to
Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
, where she received a degree in
zoology Zoology ( , ) is the scientific study of animals. Its studies include the anatomy, structure, embryology, Biological classification, classification, Ethology, habits, and distribution of all animals, both living and extinction, extinct, and ...
in 1954. She met George DeCoursey at Cornell University, where he was a student at the time. She married George DeCoursey in 1954. DeCoursey furthered her education at the
University of Wisconsin, Madison A university () is an institution of tertiary education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase , which roughly means "community of teachers and scholars". Univ ...
where she earned a Ph.D. in zoology and
biochemistry Biochemistry, or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, a ...
. She did postdoctoral research with Jürgen Aschoff at the Max-Planck Institute for Behavioral Physiology in Erling-Andech, Germany for two years. She then continued her research at
Washington State University Washington State University (WSU, or colloquially Wazzu) is a Public university, public Land-grant university, land-grant research university in Pullman, Washington, United States. Founded in 1890, WSU is also one of the oldest Land-grant uni ...
,


Career

DeCoursey was a distinguished professor of biology at
University of South Carolina The University of South Carolina (USC, SC, or Carolina) is a Public university, public research university in Columbia, South Carolina, United States. Founded in 1801 as South Carolina College, It is the flagship of the University of South Car ...
, researching mammalian circadian rhythms since she moved there with her husband in 1966.


Death

DeCoursey died in
Columbia, South Carolina Columbia is the List of capitals in the United States, capital city of the U.S. state of South Carolina. With a population of 136,632 at the 2020 United States census, 2020 census, it is List of municipalities in South Carolina, the second-mo ...
on January 1, 2022, at the age of 89.


Contributions to chronobiology


Phase Response Curve

Decoursey is credited with the first published Phase Response Curve (PRC). The relevant paper was about flying squirrels kept in constant darkness and how they would respond to different pulses of light at different times of the day. The compilation of this data produced the first PRC.Zivkovic, Bora; aka "Coturnix" (2007). "Clock Tutorial #3c - Darwin On Time". A Blog Around the Clock. ScienceBlogs LLC)


Mammalian Entrainment System

DeCoursey was the first scientist to show that the mammalian clocks can be reset by light pulses. She also showed that the photoreceptive system responsible for
entrainment Entrainment may refer to: * Air entrainment, the intentional creation of tiny air bubbles in concrete * Brainwave entrainment, the practice of entraining one's brainwaves to a desired frequency * Entrainment (biomusicology), the synchronization o ...
is different from the system involved in visual image perception.


Adaptive Value

DeCoursey helped the scientific world understand the adaptive value of the mammalian biological clocks (found within the
suprachiasmatic nucleus The suprachiasmatic nucleus or nuclei (SCN) is a small region of the brain in the hypothalamus, situated directly above the optic chiasm. It is responsible for regulating sleep cycles in animals. Reception of light inputs from photosensitive r ...
(SCN)). From April 1997-October 1998 she set up an enclosure for approximately 74 chipmunks. 30 chipmunks had lesions in their SCN, 24 others were surgical control and 20 others were intact controls. After 80 days she showed that the majority of the chipmunks killed by predators had lesions in their SCN. This gave evidence to support that having a mammalian circadian clock is a favorable trait that has been naturally selected for. In an outdoor enclosure, DeCoursey released white-tailed antelope ground squirrels which had various levels of SCN lesioned. The squirrels displaying the most activity during the night had the highest amount of lesioning. This research has helped further our understanding of sleep related issues affecting humans such as
jet lag Jet lag is a temporary physiological condition that occurs when a person's circadian rhythm is out of sync with the time zone they are in, and is a typical result from travelling rapidly across multiple time zones (east–west or west–east). ...
or
insomnia Insomnia, also known as sleeplessness, is a sleep disorder where people have difficulty sleeping. They may have difficulty falling asleep, or staying asleep for as long as desired. Insomnia is typically followed by daytime sleepiness, low ene ...
.


Later research

Her later research focused on the physiological and behavioral aspects of
circadian rhythms A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., endogenous) and responds to the environment (is entrai ...
. She studied how the retina moves in response to the daily rhythm. Also, as mentioned above, her work on chipmunks helped uncover the adaptive value of the circadian clock in the wild. She has done experiments related to the adaptive value of clocks on antelope squirrels and golden-mantled squirrels. This research furthers our understanding of sleep-related issues affecting humans such as
jet lag Jet lag is a temporary physiological condition that occurs when a person's circadian rhythm is out of sync with the time zone they are in, and is a typical result from travelling rapidly across multiple time zones (east–west or west–east). ...
or
insomnia Insomnia, also known as sleeplessness, is a sleep disorder where people have difficulty sleeping. They may have difficulty falling asleep, or staying asleep for as long as desired. Insomnia is typically followed by daytime sleepiness, low ene ...
.


Other achievements

DeCoursey received the 2011 South Carolina Environmental Awareness Award for re-foresting the W. Gordon Belser Arboretum at the University of South Carolina, a ten-year initiative she led, as well as for various small gardens around the university. The arboretum is designated as an outdoor field classroom and laboratory for UofSC undergraduates, and it is also used for conducting a variety of educational outreach programs. According to an article in
Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it, with more than 150 Nobel Pri ...
, DeCoursey "spends half her work time on the restoring the arboretum and organizing class visits, and the other half on her professorial duties." Decoursey was a member of the original Organizing Committees for both the Journal of Biological Rhythms and the Society for Research on Biological Rhythms (SRBR). She was an active member on the Advisory Board for both groups and served two terms as SRBR’s Secretary. DeCoursey was one of the activists who worked to create what is now the
Congaree National Park Congaree National Park is a national park of the United States in central South Carolina, 18 miles southeast of the state capital, Columbia. The park preserves the largest tract of old growth bottomland hardwood forest left in the United Sta ...
.


Selected publications

* * * *DeCoursey PJ (1989) Photoentrainment of circadian rhythms: An ecologist’ viewpoint In Circadian Clocks and Ecology, T Hiroshige and K Honma, eds, pp 187–206, Hokkaido University Press, Sapporo.


References


External links


Vanderbilt’s summary of PRCDeCoursey’s Textbook: Summary & About the Authors
{{DEFAULTSORT:DeCoursey, Patricia 1932 births 2022 deaths 21st-century American biologists American chronobiologists Cornell University alumni University of Wisconsin–Madison College of Letters and Science alumni University of South Carolina faculty