Ccs. Donaldson et al., DISINHIBITION IN THE GAMMA-MOTONEURON CIRCUITRY - A NEGLECTED MECHANISM FOR UNDERSTANDING MYOFASCIAL PAIN SYNDROMES, Applied psychophysiology and biofeedback, 23(1), 1998, pp. 43-57
Dysregulation in the gamma motoneuron circuitry is proposed as one mec
hanism to explain the development of trigger point activity in myofasc
ial pain syndrome. Dysregulation in this context is defined operationa
lly as significantly (and functionally) different levels of electrical
activity detected in the same muscle on the left and right sides of t
he body that is persistently present with movement of that muscle. Neu
rophysiological concepts as they pertain to muscles and motor control
principles are reviewed. Research is integrated that ties together mat
erial from diverse fields of psychology and medicine. Dysregulation in
the gamma motoneuron circuitry may lead to disinhibition of muscle th
at causes it to remain hyperactive after contraction, generate excessi
ve electrical activity during movement, and/or inappropriately coactiv
ate with other muscles during movement. Any or all of these phenomena
may occur with dysregulation. Such dysregulation may be corrected by l
earning, Immediate clinical implications are discussed, including the
addition of specifically targeted neuromuscular retraining procedures
via surface electromyography, as well as some conceptual and research
issues that require further clarification.