Dr. Pingfu (Dale) Feng, a member of the Sleep Research Society since 1992, and a founding member in 1990 of the Chinese Sleep Research Society member, died suddenly August 22, 2021. He was an experimentalist linked to those with original ideas on sleep functions, the ontogeny of REM sleep, and how disruption of neonatal sleep and REM sleep in particular could influence behavior in adult life, deploying quantitative correlates to depression- helplessness, memory, and anhedonia- in preclinical models.
Dr. Feng was born in Henan, China on June 22, 1953. In 1976 he obtained his MD from Henan Medical University in 1976 and trained as a resident physician at Anyang Hospital. He went on to obtain a Master of Science degree in neuroscience at Henan Medical University in 1985, followed by a PhD in neurophysiology from Hunan Medical College in 1988. One research mentor directed him to measure brain electrical activity in chicken embryos, and by recording bipolar EEG signals, he described cycles of low activity and muscle twitches consistent with active sleep. In 1989, Dr. Feng immigrated to the United States for post-doctoral training first at the University of Texas Southwestern Medical Center at Dallas in the Roffwarg laboratory, and then at the University of Chicago in the Rechtschaffen laboratory. There he ran the lab’s disc-over-water model for chronic (and lethal) sleep deprivation. His first authored paper from that time confirmed the presence of bacteremia in the end-stage of nearly total deprivation, compared to none in the yoked controls, a finding that suggested a profound effect of the model on host defense.
Dr. Feng then moved to Emory University School of Medicine as an Instructor and then Assistant Professor where Drs. Gerald Vogel and then Bernard Bergmann were expanding on Dr. Vogel’s theory of a role for the ontogeny of REM sleep on neurotransmitter and brain networks, producing risks for endogenous depression. He described the timecourse of REM expression in rat pups to the point where NREM/REM cycles were clearly apparent. His studies focused on how REM deprivation in the neonatal period produced behaviors consistent with depression in adult rats. He observed this in models of REM deprivation in neonates by drugs (clomipramine) and by instrumental intervention (as in the Rechtschaffen model).
In 2003, Dr. Feng was recruited as an Associate Professor of Psychiatry, and developed his research laboratory at the Louis Stokes Cleveland VA Medical Center. He was awarded national and federal grants to continue his work on the Vogel model, moving into descriptions of neurotransmitter levels in the adult brain associated with the behavioral traits. At times he was assisted by his wife, Xiaoping Yang, who contributed expertise in immunohistochemistry and immunoblotting. Dr. Feng supervised an active group with 12 working sleep recording chambers, built from Coleman coolers to provide control of light, sound, temperature, and humidity for recording over weeks in the adult rat, as well as tanks and mazes for measuring behavioral traits. He served as a grant reviewer locally and on multiple occasions for the national VA Research Service and the Department of Defense Medical Research Programs. He published many peer-reviewed papers addressing brain behavioral, circadian, and breathing networks in rats and mice. One memorable study was the observation that the same antidepressant given to the neonatal rat to produce adult depression–like traits, could reverse those traits when give to the adult animal. He was the recipient of the National Alliance for Research in Schizophrenia and Depression’s Young Investigator Award in 2004.
Dr. Feng was successful in obtaining national, federal, and industry funds for this line of work on depression in the preclinical models. Another line of collaborative funding was technology to estimate sleep-wake cycles and breathing in untethered mice, with the goal of making an inexpensive high-throughput approach for monitoring novel compounds for depression and insomnia. Another collaboration involved genetic differences in the control of breathing, which evolved into an interest in drug treatment for sleep apnea. In 2019 he retired from the university and VA system and proceeded to create a research and development company in New Jersey targeting this new direction.
His research resonates today with the pandemic-accelerated rates of depression, the increasing use of anti-depressants (many REM suppressing) in pregnancy, sleep disruptions with child refugee displacement, and fundamentally REM sleep in neonatal neurodevelopment.
He was an animated speaker and teacher. He actively promoted sleep research, teaching bewildered MDs in Sleep Medicine relevant neurobiology in a Socratic fashion, presenting at annual meetings of the SRS and the CSRS. He continued to mentor graduate students, some remotely in Hunan Medical College and was interested to restart interest in the chicken embryo as a model system.
He is survived by his wife of 40 years, Xiaoping Yang, his sons, Yu and James, a daughter-in-law, Yan Yuan, and two grandchildren, Alexandria and Max.
Prepared by Kingman Strohl and Michael Decker, Case Western Reserve University, Cleveland OH, USA, and Fang Han, Peking University People’s Hospital, Beijing CHINA.