Richard Stephenson

Professor Emeritus


St. George (downtown)

CSB Appointment


Research Areas

Animal Biology, Neurobiology, Physiology


Ph.D. University of Birmingham 1987
B.Sc. University of Sheffield 1982

Primary Undergraduate Department

Cell & Systems Biology

Graduate Programs

Cell & Systems Biology

Research Description

Regulation and function of sleep.

Contact Information

Office Phone: 416-978-3491
Office: RW325C
Lab: RW325/RW327
Lab Phone: 416-946-7237

Mailing Address

Department of Cell & Systems Biology
University of Toronto
25 Harbord St.
Toronto, ON M5S 3G5



Statistical properties of sleep-wake behavior in the rat and their relation to circadian and ultradian phases

Stephenson R, Famina S, Caron AM, Lim J
2013, Sleep, 36, 1377-90, 23997372

A simple model for the origin of quasiperiodic ultradian rhythms in sleep-wake state in the rat

Stephenson R
2013, Communicative & integrative biology, 6, e22433, 23802038

Back to top


Sleep-wake behavior in the rat: ultradian rhythms in a light-dark cycle and continuous bright light

Stephenson R, Lim J, Famina S, Caron AM, Dowse HB
2012, Journal of biological rhythms, 27, 490-501, 23223374

Back to top


Sleep homeostasis: Progress at a snail’s pace

Stephenson R
2011, Communicative & integrative biology, 4, 446-9, 21966567

Behavioural evidence for a sleep-like quiescent state in a pulmonate mollusc, Lymnaea stagnalis (Linnaeus)

Stephenson R, Lewis V
2011, The Journal of experimental biology, 214, 747-56, 21307060

Back to top


Energy expenditure is affected by rate of accumulation of sleep deficit in rats

Caron AM, Stephenson R
2010, Sleep, 33, 1226-35, 20857870

Back to top


Automated analysis of sleep-wake state in rats

Stephenson R, Caron AM, Cassel DB, Kostela JC
2009, Journal of neuroscience methods, 184, 263-74, 19703489

Back to top


Prolonged deprivation of sleep-like rest raises metabolic rate in the Pacific beetle cockroach, Diploptera punctata (Eschscholtz)

Stephenson R, Chu KM, Lee J
2007, The Journal of experimental biology, 210, 2540-7, 17601958

Circadian rhythms and sleep-related breathing disorders

Stephenson R
2007, Sleep medicine, 8, 681-7, 17387041

Back to top


The effect of time of day on apnoea index in the sleeping rat

Stephenson R, Horner RL
2006, Respiratory physiology & neurobiology, 154, 351-5, 16554190

Back to top


A visual aid for computer-based analysis of sleep-wake state in rats

Mileva-Seitz VR, Louis RP, Stephenson R
2005, Journal of neuroscience methods, 148, 43-8, 15885800

A theoretical analysis of diving performance in the Weddell seal (Leptonychotes weddelli)

Stephenson R
2005, Physiological and biochemical zoology : PBZ, 78, 782-800, 16059847

Physiological control of diving behaviour in the Weddell seal Leptonychotes weddelli: a model based on cardiorespiratory control theory

Stephenson R
2005, The Journal of experimental biology, 208, 1971-91, 15879077

Back to top


A theoretical study of the effect of circadian rhythms on sleep-induced periodic breathing and apnoea

Stephenson R
2004, Respiratory physiology & neurobiology, 139, 303-19, 15122996

Design and validation of a computer-based sleep-scoring algorithm

Louis RP, Lee J, Stephenson R
2004, Journal of neuroscience methods, 133, 71-80, 14757347

Back to top


Do circadian rhythms in respiratory control contribute to sleep-related breathing disorders?

Stephenson R
2003, Sleep medicine reviews, 7, 475-90, 15018091

Back to top


Theoretical and practical considerations in the application of whole body plethysmography to sleep research

Stephenson R, Gucciardi EJ
2002, European journal of applied physiology, 87, 207-19, 12111280

Back to top


Circadian rhythms and sleep have additive effects on respiration in the rat

Stephenson R, Liao KS, Hamrahi H, Horner RL
2001, The Journal of physiology, 536, 225-35, 11579171

Respiratory control in neonatal mice with NADPH oxidase deficiency

Kazemian P, Stephenson R, Yeger H, Cutz E
2001, Respiration physiology, 126, 89-101, 11348637

Selected Contribution: Regulation of sleep-wake states in response to intermittent hypoxic stimuli applied only in sleep

Hamrahi H, Stephenson R, Mahamed S, Liao KS, Horner RL
2001, Journal of applied physiology (Bethesda, Md. : 1985), 90, 2490-501, 11356818

Back to top


Effects of hypoxia and hypercapnia on circadian rhythms in the golden hamster (Mesocricetus auratus)

Jarsky TM, Stephenson R
2000, Journal of applied physiology (Bethesda, Md. : 1985), 89, 2130-8, 11090559

A model of the chemoreflex control of breathing in humans: model parameters measurement

Duffin J, Mohan RM, Vasiliou P, Stephenson R, Mahamed S
2000, Respiration physiology, 120, 13-26, 10786641

Circadian rhythms in the chemoreflex control of breathing

Stephenson R, Mohan RM, Duffin J, Jarsky TM
2000, American journal of physiology. Regulatory, integrative and comparative physiology, 278, R282-6, 10644650

Back to top


Circadian rhythms in diving behavior and ventilatory response to asphyxia in canvasback ducks

Woodin M, Stephenson R
1998, The American journal of physiology, 274, R686-93, 9530234

Back to top


Day-night differences in the respiratory response to hypercapnia in awake adult rats

Peever JH, Stephenson R
1997, Respiration physiology, 109, 241-8, 9342801

Back to top


Respiratory and plumage gas volumes in unrestrained diving ducks (Aythya affinis)

Stephenson R
1995, Respiration physiology, 100, 129-37, 7624614

Back to top


Regional cerebral blood flow during submergence asphyxia in Pekin duck

Stephenson R, Jones DR, Bryan RM
1994, The American journal of physiology, 266, R1162-8, 8184958

Back to top


Metabolic responses to forced dives in Pekin duck measured by indirect calorimetry and 31P-MRS

Stephenson R, Jones DR
1992, The American journal of physiology, 263, R1309-17, 1481944

Back to top