Faculty Book
CHRISTINE K. THOMAS, Ph.D.
Professor, Neurological Surgery
Neuromuscular weakness, fatigue, spasms and regeneration
Research
Interests
My research has addressed issues relating to peripheral nerve regeneration, neuromuscular fatigue, weakness and spasms. Much of this work has involved human subjects and has required the use of surface and intramuscular EMG recordings at the whole muscle or single motor unit levels, intraneural stimulation and recording techniques, as well as measurements of peripheral and central conduction using electrical and magnetic stimulation. Now this knowledge is being applied to examine the neurophysiology of human spinal cord injury.
We have documented that muscle weakness and atrophy is often severe after human spinal cord injury. It relates to partial paralysis, denervation and/or disuse. Muscles paralyzed completely or partially by spinal cord injury are also highly fatigable. We aim to quantify this excessive force loss, to determine the factors that contribute to this fatigue and to analyze whether the fatigue sites are central and/or peripheral. Information from these studies may help improve systems used for functional electrical stimulation of paralyzed muscles.
Other projects examine spasms because muscles that are paralyzed by spinal cord injury are not always quiescent. A few weeks after injury, it is common for paralyzed muscles to contract involuntarily. Our research examines how extensive and intense this activity of paralyzed muscles is because on-going neural activity may prevent some muscle deterioration.
Our research has also expanded to include studies in rats. These studies aim to develop ways to ameliorate denervated-induced muscle atrophy. We have shown that some function can be restored to denervated muscles by reinnervation from axons that grow from embryonic ventral spinal cord cells transplanted into nearby peripheral nerve. The reinnervated muscles are weak, however. Thus, our current studies aim to improve the strength of these reinnervated muscles.
Video Introduction
Thomas CK, Sesodia S, Erb DE, Grumbles RM. Properties of medial gastrocnemius motor units and muscle fibers reinnervated by embryonic ventral spinal cord cells. Exp Neurol. 2003 Mar;180(1):25-31. [Abstract]
Thomas CK, Nelson G, Than L, Zijdewind I. Motor unit activation order during electrically evoked contractions of paralyzed or partially paralyzed muscles. Muscle Nerve. 2002 Jun;25(6):797-804. [Abstract]
Godfrey S, Butler JE, Griffin L, Thomas CK. Differential fatigue of paralyzed thenar muscles by stimuli of different intensities. Muscle Nerve. 2002 Jul;26(1):122-31. [Abstract]
Grumbles RM, Wood P, Rudinsky M, Gomez AM, Thomas CK. Muscle reinnervation with delayed or immediate transplant of embryonic ventral spinal cord cells into adult rat peripheral nerve. Cell Transplant. 2002;11(3):241-50. [Abstract]
Thomas CK, Erb DE, Grumbles RM, Bunge RP. Embryonic cord transplants in peripheral nerve restore skeletal muscle function. J Neurophysiol. 2000 Jul;84(1):591-5. [Abstract]
Griffin L, Godfrey S, Thomas CK. Stimulation pattern that maximizes force in paralyzed and control whole thenar muscles. J Neurophysiol. 2002 May;87(5):2271-8. [Abstract]
Thomas CK, Griffin L, Godfrey S, Ribot-Ciscar E, Butler JE. Fatigue of paralyzed and control thenar muscles induced by variable or constant frequency stimulation. J Neurophysiol. 2003 Apr;89(4):2055-64. [Abstract]
last updated: June 19, 2003
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