Our lab takes a comprehensive approach to understanding the skin senses, including both touch and pain.  We study these sensory modalities individually, but are also looking at ways in which they interact.

A major focus of our current research is pain in sickle cell disease (SCD).  This disease causes episodes of intense pain, separated (in many patients) by periods of relief.  SCD is a genetic disorder that primarily strikes people of African descent; it affects approximately 1 in 600 African Americans.  While much is known about the physiological basis of this condition, much less is known about the sensory processing of pain signals in SCD.  Our current research, funded by NIH, brings together a strong group of investigators including Mark Hollins (PI); Professor Karen Gil, an expert in pain coping mechanisms in SCD and other conditions; Gregory Stonerock, a graduate student in the Clinical Psychology program; Nkaku Kisaalita, research technician; Susan Jones, RN, a research nurse in UNC’s Sickle Cell Clinic; and Eugene Orringer, MD, Professor of Hematology and a leading authority on SCD.

Experimentally induced pain is known to interfere with our ability to detect vibration, a phenomenon called “touch gating.”  We wanted to know whether clinical pain would have the same effect. To examine this, our lab teamed up with researchers in UNC’s School of Dentistry.  Through our continuing involvement in an NIH-funded program project, we have shown that many individuals with chronic pain in the lower face (temporomandibular joint disorder, TMJD) are impaired at detecting vibration, presumably because of touch gating.  Another experiment conducted in our lab revealed that the effects of touch gating are not limited to vibration:  Professor Atsuki Higashiyama, while on a visit to our lab from Ritsumeikan University in Japan, led a team that discovered that higher-level perception is also affected.  Our current work continues to explore the full implications of touch gating, in healthy individuals as well as individuals with chronic pain.  Touch gating is important, because we suspect that pain patients with an impaired sense of touch are more likely to fall or otherwise injure themselves.

But the connection between vibration sensitivity (a form of touch) and pain is a two-way street.  Just as pain can interfere with touch, touch can (under the right conditions) reduce pain, a phenomenon called “pain gating.”  Current work in our lab aims to determine the parameters of stimulation that produce the most effective pain reduction, and why they do so.  Another phenomenon we are studying is diffuse noxious inhibitory controls (DNIC), a process in which one pain suppresses another pain.  An example of DNIC is when someone bites their lip to reduce the pain from stubbing their toe.  We believe that DNIC is important because the mechanism may be altered in individuals with chronic pain.  We are currently in the middle of a systematic study to measure touch gating, pain gating, and DNIC in the same subjects.  Some of these subjects have TMJD, some have fibromyalgia (a condition characterized by intense, chronic pain in many areas of the body), and some are healthy controls with no chronic pain.  By studying sensory interactions we hope to get a better overall understanding of the pathophysiology of these severe pain conditions.  The team working on this research includes Mark Hollins (PI); Daniel Harper, a graduate student in the Behavioral Neuroscience program; Shannon Gallagher, research technician; Dr. Muhammad Siddiqi, in the School of Dentistry, who recruits and screens participants for the study; and Professor William Maixner, Director of the Center for Neurosensory Disorders in the Dental School, and a leading authority on TMJD pain.

The area of sensory research is an interdisciplinary field. It has traditionally attracted scientists from many disciplines, including psychology, biology, physics, mathematics, and philosophy, as well as medicine and dentistry.  Perhaps for this same reason, students from a variety of departments have participated in the work of the Somatosensory Research Lab over the years—including students majoring in or pursuing graduate study in Psychology, Physics, Biomedical Engineering, Neurobiology, and Operations Research.

Our team approach allows each student to mature as a unique researcher, benefiting from many perspectives but developing special expertise in those aspects of research in which he or she excels. If you have an interest in our research, feel free to stop by our lab or send us an email.                   

To learn more about the lab members click here