A commonly proposed neural pathway suggested to form the basis of a pain-spasm-pain cycle. Specifically, it has been suggested that feedback of nociceptive afferents (N) on the gamma-motorneurons (γ) will increase the sensitivity of the muscle spindles (S) to stretch, which results in direct and indirect excitatory input (E) to the alpha-motorneurons (α) that will subsequently increase muscle activation. Reprinted from van Dieen et al., J Electromyogr Kineesiol. 13(4): 333-351, 2003.
Clark et al. BMC Musculoskeletal Disorders 2011 12:170 doi:10.1186/1471-2474-12-170