Sir Isaac Newton once referred to the process of discovery as “standing on the shoulders of giants,” meaning that revolutionary science and innovation is built on the work of previous researchers. Some researchers are more impactful than others. One measure of this is the number of times a particular researcher’s work is cited, thus serving as a starting point for yet another discovery.

Thomson Reuters generates an annual Highly Cited Researchers list to fully assess those who have made the most foundational contributions to their field. To do this, they first pull the most highly cited papers in each scientific field, then count the number of these papers attributed to each author. In total, there are 3,000 authors across 21 different scientific fields. This year, the Keck School of Medicine of USC is proud to lay claim to seven of those researchers.

“This acknowledgement of the Keck School of Medicine’s excellence in research is particularly significant as this research is vital to new disease and treatment discoveries, which ultimately give our patients — and patients around the world — hope for improved outcomes and cures for disease,” said Rohit Varma, MD, MPH, dean of the Keck School and director of the USC Gayle and Edward Roski Eye Institute. “It is a testament to the Keck School’s growing prominence as a research-intensive academic medical center and I am delighted for my colleagues who have made this important list.”

The list includes:

Arthur Toga, PhD, Provost Professor of Ophthalmology — Toga currently is the director of the USC Mark and Mary Stevens Neuroimaging and Informatics Institute. He has long been an acclaimed figure for his brain mapping and data aggregation strategies. His research teams have developed advanced algorithms and scientific approaches in neuroimaging, using massive data sets to tackle some of the most complex neurological diseases like epilepsy, Alzheimer’s disease, and autism.

Berislav Zlokovic, MD, PhD, chair and professor of physiology and biophysics — Zlokovic is the director of the Zilkha Neurogenetic Institute (ZNI) and an internationally renowned leader in Alzheimer’s disease and stroke research. He has published more than 250 articles, many of them in the most high-impact journals, and received awards from national institutes for his work. His multidisciplinary approach to understanding neurodegenerative disorders continues to spur groundbreaking, original science both at USC and throughout the world.

Paul Aisen, MD, professor of neurology — Aisen is the founding director of the Alzheimer’s Therapeutic Research Institute (ATRI) and a leading expert in Alzheimer’s research. He has led a number of large, multicenter clinical trials testing therapies that may delay or prevent the disease. Among his current projects is his research on those who may be exhibiting physiological indications of pre-Alzheimer’s without displaying symptoms or loss or cognitive function. This research may change how Alzheimer’s is screened and treated in the future.

Huaiyu Mi, PhD, associate professor of research preventive medicine — Mi was among the group involved in the first human genome sequencing project in 2000. He managed the development of Protein Analysis Through Evolutionary Relationships (PANTHER) Classification System, and led the development of PANTHER Pathway. In 2006, he contributed to the development of Systems Biology Graphical Notation (SBGN), a form of communicating information about signaling pathways and metabolic networks that is used today by everyone from high school students to the world’s top scientists.

Paul Thomas, PhD, associate professor of preventive medicine — Thomas worked alongside Mi on the PANTHER project and co-authored the overview of the function and evolution of human genes. His current lab focuses on the development and application of computational methods for reconstructing gene evolution, using these techniques to understand the function of human genes and how genetic factors may impact disease risk.

Paul Thompson, PhD, professor of ophthalmology, neurology, psychiatry and the behavioral sciences, radiology, psychiatry, and engineering — Thompson works closely with Toga as the associate director of the USC Stevens Neuroimaging and Informatics Institute. He also leads the ENIGMA research consortium, which has 30 active working groups worldwide to better understand brain structure and function using imaging and genetic data.

Steve Kay, PhD, Provost Professor of Neurology, Biomedical Engineering and Biological Sciences — Kay is among the most prominent chronobiologists, having made a number of scientific breakthroughs related to gene expression and circadian rhythms. He is a member of the National Academy of Sciences and a former American Association for the Advancement of Science fellow. His current research explores how internal clocks regulate various processes in plants and mammals.

Four other faculty members from across the university also were among the world’s most highly cited researchers: Raymond Stevens, PhD, provost professor of biological sciences and chemistry; Valery Fokin, PhD, professor of chemistry; Vadim Cherezov, PhD, professor of chemistry and professor of physics and astronomy; and Seva Katritch, PhD, assistant professor of biological sciences. You can review the full list at

— Mary Dacuma